2005-04-17 06:20:36 +08:00
|
|
|
/*
|
|
|
|
* linux/drivers/cpufreq/cpufreq.c
|
|
|
|
*
|
|
|
|
* Copyright (C) 2001 Russell King
|
|
|
|
* (C) 2002 - 2003 Dominik Brodowski <linux@brodo.de>
|
2013-06-19 16:49:33 +08:00
|
|
|
* (C) 2013 Viresh Kumar <viresh.kumar@linaro.org>
|
2005-04-17 06:20:36 +08:00
|
|
|
*
|
2005-10-31 06:59:54 +08:00
|
|
|
* Oct 2005 - Ashok Raj <ashok.raj@intel.com>
|
2006-02-28 13:43:23 +08:00
|
|
|
* Added handling for CPU hotplug
|
2006-03-05 16:37:23 +08:00
|
|
|
* Feb 2006 - Jacob Shin <jacob.shin@amd.com>
|
|
|
|
* Fix handling for CPU hotplug -- affected CPUs
|
2005-10-31 06:59:54 +08:00
|
|
|
*
|
2005-04-17 06:20:36 +08:00
|
|
|
* This program is free software; you can redistribute it and/or modify
|
|
|
|
* it under the terms of the GNU General Public License version 2 as
|
|
|
|
* published by the Free Software Foundation.
|
|
|
|
*/
|
|
|
|
|
2012-10-23 07:29:03 +08:00
|
|
|
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
|
|
|
|
|
2013-08-07 01:23:03 +08:00
|
|
|
#include <linux/cpu.h>
|
2005-04-17 06:20:36 +08:00
|
|
|
#include <linux/cpufreq.h>
|
|
|
|
#include <linux/delay.h>
|
|
|
|
#include <linux/device.h>
|
2013-08-07 01:23:03 +08:00
|
|
|
#include <linux/init.h>
|
|
|
|
#include <linux/kernel_stat.h>
|
|
|
|
#include <linux/module.h>
|
2006-01-14 07:54:22 +08:00
|
|
|
#include <linux/mutex.h>
|
2013-08-07 01:23:03 +08:00
|
|
|
#include <linux/slab.h>
|
cpufreq: Use syscore_ops for boot CPU suspend/resume (v2)
The cpufreq subsystem uses sysdev suspend and resume for
executing cpufreq_suspend() and cpufreq_resume(), respectively,
during system suspend, after interrupts have been switched off on the
boot CPU, and during system resume, while interrupts are still off on
the boot CPU. In both cases the other CPUs are off-line at the
relevant point (either they have been switched off via CPU hotplug
during suspend, or they haven't been switched on yet during resume).
For this reason, although it may seem that cpufreq_suspend() and
cpufreq_resume() are executed for all CPUs in the system, they are
only called for the boot CPU in fact, which is quite confusing.
To remove the confusion and to prepare for elimiating sysdev
suspend and resume operations from the kernel enirely, convernt
cpufreq to using a struct syscore_ops object for the boot CPU
suspend and resume and rename the callbacks so that their names
reflect their purpose. In addition, put some explanatory remarks
into their kerneldoc comments.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
2011-03-24 05:16:32 +08:00
|
|
|
#include <linux/syscore_ops.h>
|
2013-08-07 01:23:03 +08:00
|
|
|
#include <linux/tick.h>
|
2010-04-20 19:17:36 +08:00
|
|
|
#include <trace/events/power.h>
|
|
|
|
|
2005-04-17 06:20:36 +08:00
|
|
|
/**
|
2006-08-12 05:59:28 +08:00
|
|
|
* The "cpufreq driver" - the arch- or hardware-dependent low
|
2005-04-17 06:20:36 +08:00
|
|
|
* level driver of CPUFreq support, and its spinlock. This lock
|
|
|
|
* also protects the cpufreq_cpu_data array.
|
|
|
|
*/
|
2013-04-29 06:08:16 +08:00
|
|
|
static struct cpufreq_driver *cpufreq_driver;
|
2008-03-26 06:06:53 +08:00
|
|
|
static DEFINE_PER_CPU(struct cpufreq_policy *, cpufreq_cpu_data);
|
cpufreq: Preserve policy structure across suspend/resume
To perform light-weight cpu-init and teardown in the cpufreq subsystem
during suspend/resume, we need to separate out the 2 main functionalities
of the cpufreq CPU hotplug callbacks, as outlined below:
1. Init/tear-down of core cpufreq and CPU-specific components, which are
critical to the correct functioning of the cpufreq subsystem.
2. Init/tear-down of cpufreq sysfs files during suspend/resume.
The first part requires accurate updates to the policy structure such as
its ->cpus and ->related_cpus masks, whereas the second part requires that
the policy->kobj structure is not released or re-initialized during
suspend/resume.
To handle both these requirements, we need to allow updates to the policy
structure throughout suspend/resume, but prevent the structure from getting
freed up. Also, we must have a mechanism by which the cpu-up callbacks can
restore the policy structure, without allocating things afresh. (That also
helps avoid memory leaks).
To achieve this, we use 2 schemes:
a. Use a fallback per-cpu storage area for preserving the policy structures
during suspend, so that they can be restored during resume appropriately.
b. Use the 'frozen' flag to determine when to free or allocate the policy
structure vs when to restore the policy from the saved fallback storage.
Thus we can successfully preserve the structure across suspend/resume.
Effectively, this helps us complete the separation of the 'light-weight'
and the 'full' init/tear-down sequences in the cpufreq subsystem, so that
this can be made use of in the suspend/resume scenario.
Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2013-07-30 06:55:10 +08:00
|
|
|
static DEFINE_PER_CPU(struct cpufreq_policy *, cpufreq_cpu_data_fallback);
|
2013-06-19 16:49:33 +08:00
|
|
|
static DEFINE_RWLOCK(cpufreq_driver_lock);
|
|
|
|
static DEFINE_MUTEX(cpufreq_governor_lock);
|
2013-08-07 01:23:08 +08:00
|
|
|
static LIST_HEAD(cpufreq_policy_list);
|
2013-06-19 16:49:33 +08:00
|
|
|
|
2007-07-10 02:35:28 +08:00
|
|
|
#ifdef CONFIG_HOTPLUG_CPU
|
|
|
|
/* This one keeps track of the previously set governor of a removed CPU */
|
2009-10-05 04:38:55 +08:00
|
|
|
static DEFINE_PER_CPU(char[CPUFREQ_NAME_LEN], cpufreq_cpu_governor);
|
2007-07-10 02:35:28 +08:00
|
|
|
#endif
|
2005-04-17 06:20:36 +08:00
|
|
|
|
2007-02-06 08:12:44 +08:00
|
|
|
/*
|
|
|
|
* cpu_policy_rwsem is a per CPU reader-writer semaphore designed to cure
|
|
|
|
* all cpufreq/hotplug/workqueue/etc related lock issues.
|
|
|
|
*
|
|
|
|
* The rules for this semaphore:
|
|
|
|
* - Any routine that wants to read from the policy structure will
|
|
|
|
* do a down_read on this semaphore.
|
|
|
|
* - Any routine that will write to the policy structure and/or may take away
|
|
|
|
* the policy altogether (eg. CPU hotplug), will hold this lock in write
|
|
|
|
* mode before doing so.
|
|
|
|
*
|
|
|
|
* Additional rules:
|
|
|
|
* - Governor routines that can be called in cpufreq hotplug path should not
|
|
|
|
* take this sem as top level hotplug notifier handler takes this.
|
2009-06-09 01:17:31 +08:00
|
|
|
* - Lock should not be held across
|
|
|
|
* __cpufreq_governor(data, CPUFREQ_GOV_STOP);
|
2007-02-06 08:12:44 +08:00
|
|
|
*/
|
2009-10-29 21:34:13 +08:00
|
|
|
static DEFINE_PER_CPU(int, cpufreq_policy_cpu);
|
2007-02-06 08:12:44 +08:00
|
|
|
static DEFINE_PER_CPU(struct rw_semaphore, cpu_policy_rwsem);
|
|
|
|
|
|
|
|
#define lock_policy_rwsem(mode, cpu) \
|
2013-02-07 18:08:42 +08:00
|
|
|
static int lock_policy_rwsem_##mode(int cpu) \
|
2007-02-06 08:12:44 +08:00
|
|
|
{ \
|
2009-10-29 21:34:13 +08:00
|
|
|
int policy_cpu = per_cpu(cpufreq_policy_cpu, cpu); \
|
2007-02-06 08:12:44 +08:00
|
|
|
BUG_ON(policy_cpu == -1); \
|
|
|
|
down_##mode(&per_cpu(cpu_policy_rwsem, policy_cpu)); \
|
|
|
|
\
|
|
|
|
return 0; \
|
|
|
|
}
|
|
|
|
|
|
|
|
lock_policy_rwsem(read, cpu);
|
|
|
|
lock_policy_rwsem(write, cpu);
|
|
|
|
|
2013-02-07 18:08:42 +08:00
|
|
|
#define unlock_policy_rwsem(mode, cpu) \
|
|
|
|
static void unlock_policy_rwsem_##mode(int cpu) \
|
|
|
|
{ \
|
|
|
|
int policy_cpu = per_cpu(cpufreq_policy_cpu, cpu); \
|
|
|
|
BUG_ON(policy_cpu == -1); \
|
|
|
|
up_##mode(&per_cpu(cpu_policy_rwsem, policy_cpu)); \
|
2007-02-06 08:12:44 +08:00
|
|
|
}
|
|
|
|
|
2013-02-07 18:08:42 +08:00
|
|
|
unlock_policy_rwsem(read, cpu);
|
|
|
|
unlock_policy_rwsem(write, cpu);
|
2007-02-06 08:12:44 +08:00
|
|
|
|
2005-04-17 06:20:36 +08:00
|
|
|
/* internal prototypes */
|
2009-01-18 14:37:11 +08:00
|
|
|
static int __cpufreq_governor(struct cpufreq_policy *policy,
|
|
|
|
unsigned int event);
|
2007-02-06 08:12:44 +08:00
|
|
|
static unsigned int __cpufreq_get(unsigned int cpu);
|
2006-11-22 22:55:48 +08:00
|
|
|
static void handle_update(struct work_struct *work);
|
2005-04-17 06:20:36 +08:00
|
|
|
|
|
|
|
/**
|
2006-02-28 13:43:23 +08:00
|
|
|
* Two notifier lists: the "policy" list is involved in the
|
|
|
|
* validation process for a new CPU frequency policy; the
|
2005-04-17 06:20:36 +08:00
|
|
|
* "transition" list for kernel code that needs to handle
|
|
|
|
* changes to devices when the CPU clock speed changes.
|
|
|
|
* The mutex locks both lists.
|
|
|
|
*/
|
[PATCH] Notifier chain update: API changes
The kernel's implementation of notifier chains is unsafe. There is no
protection against entries being added to or removed from a chain while the
chain is in use. The issues were discussed in this thread:
http://marc.theaimsgroup.com/?l=linux-kernel&m=113018709002036&w=2
We noticed that notifier chains in the kernel fall into two basic usage
classes:
"Blocking" chains are always called from a process context
and the callout routines are allowed to sleep;
"Atomic" chains can be called from an atomic context and
the callout routines are not allowed to sleep.
We decided to codify this distinction and make it part of the API. Therefore
this set of patches introduces three new, parallel APIs: one for blocking
notifiers, one for atomic notifiers, and one for "raw" notifiers (which is
really just the old API under a new name). New kinds of data structures are
used for the heads of the chains, and new routines are defined for
registration, unregistration, and calling a chain. The three APIs are
explained in include/linux/notifier.h and their implementation is in
kernel/sys.c.
With atomic and blocking chains, the implementation guarantees that the chain
links will not be corrupted and that chain callers will not get messed up by
entries being added or removed. For raw chains the implementation provides no
guarantees at all; users of this API must provide their own protections. (The
idea was that situations may come up where the assumptions of the atomic and
blocking APIs are not appropriate, so it should be possible for users to
handle these things in their own way.)
There are some limitations, which should not be too hard to live with. For
atomic/blocking chains, registration and unregistration must always be done in
a process context since the chain is protected by a mutex/rwsem. Also, a
callout routine for a non-raw chain must not try to register or unregister
entries on its own chain. (This did happen in a couple of places and the code
had to be changed to avoid it.)
Since atomic chains may be called from within an NMI handler, they cannot use
spinlocks for synchronization. Instead we use RCU. The overhead falls almost
entirely in the unregister routine, which is okay since unregistration is much
less frequent that calling a chain.
Here is the list of chains that we adjusted and their classifications. None
of them use the raw API, so for the moment it is only a placeholder.
ATOMIC CHAINS
-------------
arch/i386/kernel/traps.c: i386die_chain
arch/ia64/kernel/traps.c: ia64die_chain
arch/powerpc/kernel/traps.c: powerpc_die_chain
arch/sparc64/kernel/traps.c: sparc64die_chain
arch/x86_64/kernel/traps.c: die_chain
drivers/char/ipmi/ipmi_si_intf.c: xaction_notifier_list
kernel/panic.c: panic_notifier_list
kernel/profile.c: task_free_notifier
net/bluetooth/hci_core.c: hci_notifier
net/ipv4/netfilter/ip_conntrack_core.c: ip_conntrack_chain
net/ipv4/netfilter/ip_conntrack_core.c: ip_conntrack_expect_chain
net/ipv6/addrconf.c: inet6addr_chain
net/netfilter/nf_conntrack_core.c: nf_conntrack_chain
net/netfilter/nf_conntrack_core.c: nf_conntrack_expect_chain
net/netlink/af_netlink.c: netlink_chain
BLOCKING CHAINS
---------------
arch/powerpc/platforms/pseries/reconfig.c: pSeries_reconfig_chain
arch/s390/kernel/process.c: idle_chain
arch/x86_64/kernel/process.c idle_notifier
drivers/base/memory.c: memory_chain
drivers/cpufreq/cpufreq.c cpufreq_policy_notifier_list
drivers/cpufreq/cpufreq.c cpufreq_transition_notifier_list
drivers/macintosh/adb.c: adb_client_list
drivers/macintosh/via-pmu.c sleep_notifier_list
drivers/macintosh/via-pmu68k.c sleep_notifier_list
drivers/macintosh/windfarm_core.c wf_client_list
drivers/usb/core/notify.c usb_notifier_list
drivers/video/fbmem.c fb_notifier_list
kernel/cpu.c cpu_chain
kernel/module.c module_notify_list
kernel/profile.c munmap_notifier
kernel/profile.c task_exit_notifier
kernel/sys.c reboot_notifier_list
net/core/dev.c netdev_chain
net/decnet/dn_dev.c: dnaddr_chain
net/ipv4/devinet.c: inetaddr_chain
It's possible that some of these classifications are wrong. If they are,
please let us know or submit a patch to fix them. Note that any chain that
gets called very frequently should be atomic, because the rwsem read-locking
used for blocking chains is very likely to incur cache misses on SMP systems.
(However, if the chain's callout routines may sleep then the chain cannot be
atomic.)
The patch set was written by Alan Stern and Chandra Seetharaman, incorporating
material written by Keith Owens and suggestions from Paul McKenney and Andrew
Morton.
[jes@sgi.com: restructure the notifier chain initialization macros]
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Chandra Seetharaman <sekharan@us.ibm.com>
Signed-off-by: Jes Sorensen <jes@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-03-27 17:16:30 +08:00
|
|
|
static BLOCKING_NOTIFIER_HEAD(cpufreq_policy_notifier_list);
|
2006-10-04 17:17:06 +08:00
|
|
|
static struct srcu_notifier_head cpufreq_transition_notifier_list;
|
2005-04-17 06:20:36 +08:00
|
|
|
|
2008-02-16 18:41:24 +08:00
|
|
|
static bool init_cpufreq_transition_notifier_list_called;
|
2006-10-04 17:17:06 +08:00
|
|
|
static int __init init_cpufreq_transition_notifier_list(void)
|
|
|
|
{
|
|
|
|
srcu_init_notifier_head(&cpufreq_transition_notifier_list);
|
2008-02-16 18:41:24 +08:00
|
|
|
init_cpufreq_transition_notifier_list_called = true;
|
2006-10-04 17:17:06 +08:00
|
|
|
return 0;
|
|
|
|
}
|
2006-11-21 03:47:18 +08:00
|
|
|
pure_initcall(init_cpufreq_transition_notifier_list);
|
2005-04-17 06:20:36 +08:00
|
|
|
|
2012-03-14 07:18:39 +08:00
|
|
|
static int off __read_mostly;
|
2012-10-26 06:51:32 +08:00
|
|
|
static int cpufreq_disabled(void)
|
2012-03-14 07:18:39 +08:00
|
|
|
{
|
|
|
|
return off;
|
|
|
|
}
|
|
|
|
void disable_cpufreq(void)
|
|
|
|
{
|
|
|
|
off = 1;
|
|
|
|
}
|
2005-04-17 06:20:36 +08:00
|
|
|
static LIST_HEAD(cpufreq_governor_list);
|
2009-01-18 14:37:11 +08:00
|
|
|
static DEFINE_MUTEX(cpufreq_governor_mutex);
|
2005-04-17 06:20:36 +08:00
|
|
|
|
2013-03-27 23:58:58 +08:00
|
|
|
bool have_governor_per_policy(void)
|
|
|
|
{
|
2013-04-29 06:08:16 +08:00
|
|
|
return cpufreq_driver->have_governor_per_policy;
|
2013-03-27 23:58:58 +08:00
|
|
|
}
|
2013-05-16 13:09:56 +08:00
|
|
|
EXPORT_SYMBOL_GPL(have_governor_per_policy);
|
2013-03-27 23:58:58 +08:00
|
|
|
|
2013-05-16 13:09:57 +08:00
|
|
|
struct kobject *get_governor_parent_kobj(struct cpufreq_policy *policy)
|
|
|
|
{
|
|
|
|
if (have_governor_per_policy())
|
|
|
|
return &policy->kobj;
|
|
|
|
else
|
|
|
|
return cpufreq_global_kobject;
|
|
|
|
}
|
|
|
|
EXPORT_SYMBOL_GPL(get_governor_parent_kobj);
|
|
|
|
|
2013-05-17 19:26:32 +08:00
|
|
|
static inline u64 get_cpu_idle_time_jiffy(unsigned int cpu, u64 *wall)
|
|
|
|
{
|
|
|
|
u64 idle_time;
|
|
|
|
u64 cur_wall_time;
|
|
|
|
u64 busy_time;
|
|
|
|
|
|
|
|
cur_wall_time = jiffies64_to_cputime64(get_jiffies_64());
|
|
|
|
|
|
|
|
busy_time = kcpustat_cpu(cpu).cpustat[CPUTIME_USER];
|
|
|
|
busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_SYSTEM];
|
|
|
|
busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_IRQ];
|
|
|
|
busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_SOFTIRQ];
|
|
|
|
busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_STEAL];
|
|
|
|
busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_NICE];
|
|
|
|
|
|
|
|
idle_time = cur_wall_time - busy_time;
|
|
|
|
if (wall)
|
|
|
|
*wall = cputime_to_usecs(cur_wall_time);
|
|
|
|
|
|
|
|
return cputime_to_usecs(idle_time);
|
|
|
|
}
|
|
|
|
|
|
|
|
u64 get_cpu_idle_time(unsigned int cpu, u64 *wall, int io_busy)
|
|
|
|
{
|
|
|
|
u64 idle_time = get_cpu_idle_time_us(cpu, io_busy ? wall : NULL);
|
|
|
|
|
|
|
|
if (idle_time == -1ULL)
|
|
|
|
return get_cpu_idle_time_jiffy(cpu, wall);
|
|
|
|
else if (!io_busy)
|
|
|
|
idle_time += get_cpu_iowait_time_us(cpu, wall);
|
|
|
|
|
|
|
|
return idle_time;
|
|
|
|
}
|
|
|
|
EXPORT_SYMBOL_GPL(get_cpu_idle_time);
|
|
|
|
|
2012-07-21 02:14:38 +08:00
|
|
|
static struct cpufreq_policy *__cpufreq_cpu_get(unsigned int cpu, bool sysfs)
|
2005-04-17 06:20:36 +08:00
|
|
|
{
|
2013-08-07 01:23:05 +08:00
|
|
|
struct cpufreq_policy *policy;
|
2005-04-17 06:20:36 +08:00
|
|
|
unsigned long flags;
|
|
|
|
|
2008-03-26 06:06:53 +08:00
|
|
|
if (cpu >= nr_cpu_ids)
|
2005-04-17 06:20:36 +08:00
|
|
|
goto err_out;
|
|
|
|
|
|
|
|
/* get the cpufreq driver */
|
2013-04-29 06:08:16 +08:00
|
|
|
read_lock_irqsave(&cpufreq_driver_lock, flags);
|
2005-04-17 06:20:36 +08:00
|
|
|
|
2013-04-29 06:08:16 +08:00
|
|
|
if (!cpufreq_driver)
|
2005-04-17 06:20:36 +08:00
|
|
|
goto err_out_unlock;
|
|
|
|
|
2013-04-29 06:08:16 +08:00
|
|
|
if (!try_module_get(cpufreq_driver->owner))
|
2005-04-17 06:20:36 +08:00
|
|
|
goto err_out_unlock;
|
|
|
|
|
|
|
|
/* get the CPU */
|
2013-08-07 01:23:05 +08:00
|
|
|
policy = per_cpu(cpufreq_cpu_data, cpu);
|
2005-04-17 06:20:36 +08:00
|
|
|
|
2013-08-07 01:23:05 +08:00
|
|
|
if (!policy)
|
2005-04-17 06:20:36 +08:00
|
|
|
goto err_out_put_module;
|
|
|
|
|
2013-08-07 01:23:05 +08:00
|
|
|
if (!sysfs && !kobject_get(&policy->kobj))
|
2005-04-17 06:20:36 +08:00
|
|
|
goto err_out_put_module;
|
|
|
|
|
2013-02-23 00:24:34 +08:00
|
|
|
read_unlock_irqrestore(&cpufreq_driver_lock, flags);
|
2013-08-07 01:23:05 +08:00
|
|
|
return policy;
|
2005-04-17 06:20:36 +08:00
|
|
|
|
2006-02-03 06:03:42 +08:00
|
|
|
err_out_put_module:
|
2013-04-29 06:08:16 +08:00
|
|
|
module_put(cpufreq_driver->owner);
|
2013-04-04 22:53:25 +08:00
|
|
|
err_out_unlock:
|
2013-04-29 06:08:16 +08:00
|
|
|
read_unlock_irqrestore(&cpufreq_driver_lock, flags);
|
2006-02-03 06:03:42 +08:00
|
|
|
err_out:
|
2005-04-17 06:20:36 +08:00
|
|
|
return NULL;
|
|
|
|
}
|
2012-07-21 02:14:38 +08:00
|
|
|
|
|
|
|
struct cpufreq_policy *cpufreq_cpu_get(unsigned int cpu)
|
|
|
|
{
|
2013-01-18 00:22:21 +08:00
|
|
|
if (cpufreq_disabled())
|
|
|
|
return NULL;
|
|
|
|
|
2012-07-21 02:14:38 +08:00
|
|
|
return __cpufreq_cpu_get(cpu, false);
|
|
|
|
}
|
2005-04-17 06:20:36 +08:00
|
|
|
EXPORT_SYMBOL_GPL(cpufreq_cpu_get);
|
|
|
|
|
2012-07-21 02:14:38 +08:00
|
|
|
static struct cpufreq_policy *cpufreq_cpu_get_sysfs(unsigned int cpu)
|
|
|
|
{
|
|
|
|
return __cpufreq_cpu_get(cpu, true);
|
|
|
|
}
|
|
|
|
|
2013-08-07 01:23:05 +08:00
|
|
|
static void __cpufreq_cpu_put(struct cpufreq_policy *policy, bool sysfs)
|
2012-07-21 02:14:38 +08:00
|
|
|
{
|
|
|
|
if (!sysfs)
|
2013-08-07 01:23:05 +08:00
|
|
|
kobject_put(&policy->kobj);
|
2013-04-29 06:08:16 +08:00
|
|
|
module_put(cpufreq_driver->owner);
|
2012-07-21 02:14:38 +08:00
|
|
|
}
|
2006-02-03 06:03:42 +08:00
|
|
|
|
2013-08-07 01:23:05 +08:00
|
|
|
void cpufreq_cpu_put(struct cpufreq_policy *policy)
|
2005-04-17 06:20:36 +08:00
|
|
|
{
|
2013-01-18 00:22:21 +08:00
|
|
|
if (cpufreq_disabled())
|
|
|
|
return;
|
|
|
|
|
2013-08-07 01:23:05 +08:00
|
|
|
__cpufreq_cpu_put(policy, false);
|
2005-04-17 06:20:36 +08:00
|
|
|
}
|
|
|
|
EXPORT_SYMBOL_GPL(cpufreq_cpu_put);
|
|
|
|
|
2013-08-07 01:23:05 +08:00
|
|
|
static void cpufreq_cpu_put_sysfs(struct cpufreq_policy *policy)
|
2012-07-21 02:14:38 +08:00
|
|
|
{
|
2013-08-07 01:23:05 +08:00
|
|
|
__cpufreq_cpu_put(policy, true);
|
2012-07-21 02:14:38 +08:00
|
|
|
}
|
2005-04-17 06:20:36 +08:00
|
|
|
|
|
|
|
/*********************************************************************
|
|
|
|
* EXTERNALLY AFFECTING FREQUENCY CHANGES *
|
|
|
|
*********************************************************************/
|
|
|
|
|
|
|
|
/**
|
|
|
|
* adjust_jiffies - adjust the system "loops_per_jiffy"
|
|
|
|
*
|
|
|
|
* This function alters the system "loops_per_jiffy" for the clock
|
|
|
|
* speed change. Note that loops_per_jiffy cannot be updated on SMP
|
2006-02-28 13:43:23 +08:00
|
|
|
* systems as each CPU might be scaled differently. So, use the arch
|
2005-04-17 06:20:36 +08:00
|
|
|
* per-CPU loops_per_jiffy value wherever possible.
|
|
|
|
*/
|
|
|
|
#ifndef CONFIG_SMP
|
|
|
|
static unsigned long l_p_j_ref;
|
2013-06-19 16:49:33 +08:00
|
|
|
static unsigned int l_p_j_ref_freq;
|
2005-04-17 06:20:36 +08:00
|
|
|
|
2006-01-15 05:20:43 +08:00
|
|
|
static void adjust_jiffies(unsigned long val, struct cpufreq_freqs *ci)
|
2005-04-17 06:20:36 +08:00
|
|
|
{
|
|
|
|
if (ci->flags & CPUFREQ_CONST_LOOPS)
|
|
|
|
return;
|
|
|
|
|
|
|
|
if (!l_p_j_ref_freq) {
|
|
|
|
l_p_j_ref = loops_per_jiffy;
|
|
|
|
l_p_j_ref_freq = ci->old;
|
2011-03-27 21:04:46 +08:00
|
|
|
pr_debug("saving %lu as reference value for loops_per_jiffy; "
|
2006-10-26 18:50:58 +08:00
|
|
|
"freq is %u kHz\n", l_p_j_ref, l_p_j_ref_freq);
|
2005-04-17 06:20:36 +08:00
|
|
|
}
|
2013-06-19 16:49:33 +08:00
|
|
|
if ((val == CPUFREQ_POSTCHANGE && ci->old != ci->new) ||
|
2005-04-29 22:40:12 +08:00
|
|
|
(val == CPUFREQ_RESUMECHANGE || val == CPUFREQ_SUSPENDCHANGE)) {
|
2006-10-26 18:50:58 +08:00
|
|
|
loops_per_jiffy = cpufreq_scale(l_p_j_ref, l_p_j_ref_freq,
|
|
|
|
ci->new);
|
2011-03-27 21:04:46 +08:00
|
|
|
pr_debug("scaling loops_per_jiffy to %lu "
|
2006-10-26 18:50:58 +08:00
|
|
|
"for frequency %u kHz\n", loops_per_jiffy, ci->new);
|
2005-04-17 06:20:36 +08:00
|
|
|
}
|
|
|
|
}
|
|
|
|
#else
|
2006-10-26 18:50:58 +08:00
|
|
|
static inline void adjust_jiffies(unsigned long val, struct cpufreq_freqs *ci)
|
|
|
|
{
|
|
|
|
return;
|
|
|
|
}
|
2005-04-17 06:20:36 +08:00
|
|
|
#endif
|
|
|
|
|
2013-06-19 16:49:34 +08:00
|
|
|
static void __cpufreq_notify_transition(struct cpufreq_policy *policy,
|
2013-03-24 14:26:43 +08:00
|
|
|
struct cpufreq_freqs *freqs, unsigned int state)
|
2005-04-17 06:20:36 +08:00
|
|
|
{
|
|
|
|
BUG_ON(irqs_disabled());
|
|
|
|
|
2013-01-18 00:22:21 +08:00
|
|
|
if (cpufreq_disabled())
|
|
|
|
return;
|
|
|
|
|
2013-04-29 06:08:16 +08:00
|
|
|
freqs->flags = cpufreq_driver->flags;
|
2011-03-27 21:04:46 +08:00
|
|
|
pr_debug("notification %u of frequency transition to %u kHz\n",
|
2006-02-01 07:53:55 +08:00
|
|
|
state, freqs->new);
|
2005-04-17 06:20:36 +08:00
|
|
|
|
|
|
|
switch (state) {
|
2006-02-01 07:53:55 +08:00
|
|
|
|
2005-04-17 06:20:36 +08:00
|
|
|
case CPUFREQ_PRECHANGE:
|
2013-07-02 19:06:28 +08:00
|
|
|
if (WARN(policy->transition_ongoing ==
|
|
|
|
cpumask_weight(policy->cpus),
|
2013-06-19 12:46:55 +08:00
|
|
|
"In middle of another frequency transition\n"))
|
|
|
|
return;
|
|
|
|
|
2013-07-02 19:06:28 +08:00
|
|
|
policy->transition_ongoing++;
|
2013-06-19 12:46:55 +08:00
|
|
|
|
2006-02-28 13:43:23 +08:00
|
|
|
/* detect if the driver reported a value as "old frequency"
|
2006-02-01 07:53:55 +08:00
|
|
|
* which is not equal to what the cpufreq core thinks is
|
|
|
|
* "old frequency".
|
2005-04-17 06:20:36 +08:00
|
|
|
*/
|
2013-04-29 06:08:16 +08:00
|
|
|
if (!(cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)) {
|
2006-02-01 07:53:55 +08:00
|
|
|
if ((policy) && (policy->cpu == freqs->cpu) &&
|
|
|
|
(policy->cur) && (policy->cur != freqs->old)) {
|
2011-03-27 21:04:46 +08:00
|
|
|
pr_debug("Warning: CPU frequency is"
|
2006-02-01 07:53:55 +08:00
|
|
|
" %u, cpufreq assumed %u kHz.\n",
|
|
|
|
freqs->old, policy->cur);
|
|
|
|
freqs->old = policy->cur;
|
2005-04-17 06:20:36 +08:00
|
|
|
}
|
|
|
|
}
|
2006-10-04 17:17:06 +08:00
|
|
|
srcu_notifier_call_chain(&cpufreq_transition_notifier_list,
|
[PATCH] Notifier chain update: API changes
The kernel's implementation of notifier chains is unsafe. There is no
protection against entries being added to or removed from a chain while the
chain is in use. The issues were discussed in this thread:
http://marc.theaimsgroup.com/?l=linux-kernel&m=113018709002036&w=2
We noticed that notifier chains in the kernel fall into two basic usage
classes:
"Blocking" chains are always called from a process context
and the callout routines are allowed to sleep;
"Atomic" chains can be called from an atomic context and
the callout routines are not allowed to sleep.
We decided to codify this distinction and make it part of the API. Therefore
this set of patches introduces three new, parallel APIs: one for blocking
notifiers, one for atomic notifiers, and one for "raw" notifiers (which is
really just the old API under a new name). New kinds of data structures are
used for the heads of the chains, and new routines are defined for
registration, unregistration, and calling a chain. The three APIs are
explained in include/linux/notifier.h and their implementation is in
kernel/sys.c.
With atomic and blocking chains, the implementation guarantees that the chain
links will not be corrupted and that chain callers will not get messed up by
entries being added or removed. For raw chains the implementation provides no
guarantees at all; users of this API must provide their own protections. (The
idea was that situations may come up where the assumptions of the atomic and
blocking APIs are not appropriate, so it should be possible for users to
handle these things in their own way.)
There are some limitations, which should not be too hard to live with. For
atomic/blocking chains, registration and unregistration must always be done in
a process context since the chain is protected by a mutex/rwsem. Also, a
callout routine for a non-raw chain must not try to register or unregister
entries on its own chain. (This did happen in a couple of places and the code
had to be changed to avoid it.)
Since atomic chains may be called from within an NMI handler, they cannot use
spinlocks for synchronization. Instead we use RCU. The overhead falls almost
entirely in the unregister routine, which is okay since unregistration is much
less frequent that calling a chain.
Here is the list of chains that we adjusted and their classifications. None
of them use the raw API, so for the moment it is only a placeholder.
ATOMIC CHAINS
-------------
arch/i386/kernel/traps.c: i386die_chain
arch/ia64/kernel/traps.c: ia64die_chain
arch/powerpc/kernel/traps.c: powerpc_die_chain
arch/sparc64/kernel/traps.c: sparc64die_chain
arch/x86_64/kernel/traps.c: die_chain
drivers/char/ipmi/ipmi_si_intf.c: xaction_notifier_list
kernel/panic.c: panic_notifier_list
kernel/profile.c: task_free_notifier
net/bluetooth/hci_core.c: hci_notifier
net/ipv4/netfilter/ip_conntrack_core.c: ip_conntrack_chain
net/ipv4/netfilter/ip_conntrack_core.c: ip_conntrack_expect_chain
net/ipv6/addrconf.c: inet6addr_chain
net/netfilter/nf_conntrack_core.c: nf_conntrack_chain
net/netfilter/nf_conntrack_core.c: nf_conntrack_expect_chain
net/netlink/af_netlink.c: netlink_chain
BLOCKING CHAINS
---------------
arch/powerpc/platforms/pseries/reconfig.c: pSeries_reconfig_chain
arch/s390/kernel/process.c: idle_chain
arch/x86_64/kernel/process.c idle_notifier
drivers/base/memory.c: memory_chain
drivers/cpufreq/cpufreq.c cpufreq_policy_notifier_list
drivers/cpufreq/cpufreq.c cpufreq_transition_notifier_list
drivers/macintosh/adb.c: adb_client_list
drivers/macintosh/via-pmu.c sleep_notifier_list
drivers/macintosh/via-pmu68k.c sleep_notifier_list
drivers/macintosh/windfarm_core.c wf_client_list
drivers/usb/core/notify.c usb_notifier_list
drivers/video/fbmem.c fb_notifier_list
kernel/cpu.c cpu_chain
kernel/module.c module_notify_list
kernel/profile.c munmap_notifier
kernel/profile.c task_exit_notifier
kernel/sys.c reboot_notifier_list
net/core/dev.c netdev_chain
net/decnet/dn_dev.c: dnaddr_chain
net/ipv4/devinet.c: inetaddr_chain
It's possible that some of these classifications are wrong. If they are,
please let us know or submit a patch to fix them. Note that any chain that
gets called very frequently should be atomic, because the rwsem read-locking
used for blocking chains is very likely to incur cache misses on SMP systems.
(However, if the chain's callout routines may sleep then the chain cannot be
atomic.)
The patch set was written by Alan Stern and Chandra Seetharaman, incorporating
material written by Keith Owens and suggestions from Paul McKenney and Andrew
Morton.
[jes@sgi.com: restructure the notifier chain initialization macros]
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Chandra Seetharaman <sekharan@us.ibm.com>
Signed-off-by: Jes Sorensen <jes@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-03-27 17:16:30 +08:00
|
|
|
CPUFREQ_PRECHANGE, freqs);
|
2005-04-17 06:20:36 +08:00
|
|
|
adjust_jiffies(CPUFREQ_PRECHANGE, freqs);
|
|
|
|
break;
|
2006-02-01 07:53:55 +08:00
|
|
|
|
2005-04-17 06:20:36 +08:00
|
|
|
case CPUFREQ_POSTCHANGE:
|
2013-06-19 12:46:55 +08:00
|
|
|
if (WARN(!policy->transition_ongoing,
|
|
|
|
"No frequency transition in progress\n"))
|
|
|
|
return;
|
|
|
|
|
2013-07-02 19:06:28 +08:00
|
|
|
policy->transition_ongoing--;
|
2013-06-19 12:46:55 +08:00
|
|
|
|
2005-04-17 06:20:36 +08:00
|
|
|
adjust_jiffies(CPUFREQ_POSTCHANGE, freqs);
|
2011-03-27 21:04:46 +08:00
|
|
|
pr_debug("FREQ: %lu - CPU: %lu", (unsigned long)freqs->new,
|
2010-04-20 19:17:36 +08:00
|
|
|
(unsigned long)freqs->cpu);
|
2011-01-04 00:50:44 +08:00
|
|
|
trace_cpu_frequency(freqs->new, freqs->cpu);
|
2006-10-04 17:17:06 +08:00
|
|
|
srcu_notifier_call_chain(&cpufreq_transition_notifier_list,
|
[PATCH] Notifier chain update: API changes
The kernel's implementation of notifier chains is unsafe. There is no
protection against entries being added to or removed from a chain while the
chain is in use. The issues were discussed in this thread:
http://marc.theaimsgroup.com/?l=linux-kernel&m=113018709002036&w=2
We noticed that notifier chains in the kernel fall into two basic usage
classes:
"Blocking" chains are always called from a process context
and the callout routines are allowed to sleep;
"Atomic" chains can be called from an atomic context and
the callout routines are not allowed to sleep.
We decided to codify this distinction and make it part of the API. Therefore
this set of patches introduces three new, parallel APIs: one for blocking
notifiers, one for atomic notifiers, and one for "raw" notifiers (which is
really just the old API under a new name). New kinds of data structures are
used for the heads of the chains, and new routines are defined for
registration, unregistration, and calling a chain. The three APIs are
explained in include/linux/notifier.h and their implementation is in
kernel/sys.c.
With atomic and blocking chains, the implementation guarantees that the chain
links will not be corrupted and that chain callers will not get messed up by
entries being added or removed. For raw chains the implementation provides no
guarantees at all; users of this API must provide their own protections. (The
idea was that situations may come up where the assumptions of the atomic and
blocking APIs are not appropriate, so it should be possible for users to
handle these things in their own way.)
There are some limitations, which should not be too hard to live with. For
atomic/blocking chains, registration and unregistration must always be done in
a process context since the chain is protected by a mutex/rwsem. Also, a
callout routine for a non-raw chain must not try to register or unregister
entries on its own chain. (This did happen in a couple of places and the code
had to be changed to avoid it.)
Since atomic chains may be called from within an NMI handler, they cannot use
spinlocks for synchronization. Instead we use RCU. The overhead falls almost
entirely in the unregister routine, which is okay since unregistration is much
less frequent that calling a chain.
Here is the list of chains that we adjusted and their classifications. None
of them use the raw API, so for the moment it is only a placeholder.
ATOMIC CHAINS
-------------
arch/i386/kernel/traps.c: i386die_chain
arch/ia64/kernel/traps.c: ia64die_chain
arch/powerpc/kernel/traps.c: powerpc_die_chain
arch/sparc64/kernel/traps.c: sparc64die_chain
arch/x86_64/kernel/traps.c: die_chain
drivers/char/ipmi/ipmi_si_intf.c: xaction_notifier_list
kernel/panic.c: panic_notifier_list
kernel/profile.c: task_free_notifier
net/bluetooth/hci_core.c: hci_notifier
net/ipv4/netfilter/ip_conntrack_core.c: ip_conntrack_chain
net/ipv4/netfilter/ip_conntrack_core.c: ip_conntrack_expect_chain
net/ipv6/addrconf.c: inet6addr_chain
net/netfilter/nf_conntrack_core.c: nf_conntrack_chain
net/netfilter/nf_conntrack_core.c: nf_conntrack_expect_chain
net/netlink/af_netlink.c: netlink_chain
BLOCKING CHAINS
---------------
arch/powerpc/platforms/pseries/reconfig.c: pSeries_reconfig_chain
arch/s390/kernel/process.c: idle_chain
arch/x86_64/kernel/process.c idle_notifier
drivers/base/memory.c: memory_chain
drivers/cpufreq/cpufreq.c cpufreq_policy_notifier_list
drivers/cpufreq/cpufreq.c cpufreq_transition_notifier_list
drivers/macintosh/adb.c: adb_client_list
drivers/macintosh/via-pmu.c sleep_notifier_list
drivers/macintosh/via-pmu68k.c sleep_notifier_list
drivers/macintosh/windfarm_core.c wf_client_list
drivers/usb/core/notify.c usb_notifier_list
drivers/video/fbmem.c fb_notifier_list
kernel/cpu.c cpu_chain
kernel/module.c module_notify_list
kernel/profile.c munmap_notifier
kernel/profile.c task_exit_notifier
kernel/sys.c reboot_notifier_list
net/core/dev.c netdev_chain
net/decnet/dn_dev.c: dnaddr_chain
net/ipv4/devinet.c: inetaddr_chain
It's possible that some of these classifications are wrong. If they are,
please let us know or submit a patch to fix them. Note that any chain that
gets called very frequently should be atomic, because the rwsem read-locking
used for blocking chains is very likely to incur cache misses on SMP systems.
(However, if the chain's callout routines may sleep then the chain cannot be
atomic.)
The patch set was written by Alan Stern and Chandra Seetharaman, incorporating
material written by Keith Owens and suggestions from Paul McKenney and Andrew
Morton.
[jes@sgi.com: restructure the notifier chain initialization macros]
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Chandra Seetharaman <sekharan@us.ibm.com>
Signed-off-by: Jes Sorensen <jes@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-03-27 17:16:30 +08:00
|
|
|
CPUFREQ_POSTCHANGE, freqs);
|
2006-02-01 07:53:55 +08:00
|
|
|
if (likely(policy) && likely(policy->cpu == freqs->cpu))
|
|
|
|
policy->cur = freqs->new;
|
2005-04-17 06:20:36 +08:00
|
|
|
break;
|
|
|
|
}
|
|
|
|
}
|
2013-06-19 16:49:33 +08:00
|
|
|
|
2013-03-24 14:26:43 +08:00
|
|
|
/**
|
|
|
|
* cpufreq_notify_transition - call notifier chain and adjust_jiffies
|
|
|
|
* on frequency transition.
|
|
|
|
*
|
|
|
|
* This function calls the transition notifiers and the "adjust_jiffies"
|
|
|
|
* function. It is called twice on all CPU frequency changes that have
|
|
|
|
* external effects.
|
|
|
|
*/
|
|
|
|
void cpufreq_notify_transition(struct cpufreq_policy *policy,
|
|
|
|
struct cpufreq_freqs *freqs, unsigned int state)
|
|
|
|
{
|
|
|
|
for_each_cpu(freqs->cpu, policy->cpus)
|
|
|
|
__cpufreq_notify_transition(policy, freqs, state);
|
|
|
|
}
|
2005-04-17 06:20:36 +08:00
|
|
|
EXPORT_SYMBOL_GPL(cpufreq_notify_transition);
|
|
|
|
|
|
|
|
|
|
|
|
/*********************************************************************
|
|
|
|
* SYSFS INTERFACE *
|
|
|
|
*********************************************************************/
|
|
|
|
|
2006-07-07 03:30:26 +08:00
|
|
|
static struct cpufreq_governor *__find_governor(const char *str_governor)
|
|
|
|
{
|
|
|
|
struct cpufreq_governor *t;
|
|
|
|
|
|
|
|
list_for_each_entry(t, &cpufreq_governor_list, governor_list)
|
2009-01-18 14:37:11 +08:00
|
|
|
if (!strnicmp(str_governor, t->name, CPUFREQ_NAME_LEN))
|
2006-07-07 03:30:26 +08:00
|
|
|
return t;
|
|
|
|
|
|
|
|
return NULL;
|
|
|
|
}
|
|
|
|
|
2005-04-17 06:20:36 +08:00
|
|
|
/**
|
|
|
|
* cpufreq_parse_governor - parse a governor string
|
|
|
|
*/
|
2008-03-06 03:28:32 +08:00
|
|
|
static int cpufreq_parse_governor(char *str_governor, unsigned int *policy,
|
2005-04-17 06:20:36 +08:00
|
|
|
struct cpufreq_governor **governor)
|
|
|
|
{
|
2006-07-07 03:30:26 +08:00
|
|
|
int err = -EINVAL;
|
2013-04-29 06:08:16 +08:00
|
|
|
|
|
|
|
if (!cpufreq_driver)
|
2006-07-07 03:30:26 +08:00
|
|
|
goto out;
|
|
|
|
|
2013-04-29 06:08:16 +08:00
|
|
|
if (cpufreq_driver->setpolicy) {
|
2005-04-17 06:20:36 +08:00
|
|
|
if (!strnicmp(str_governor, "performance", CPUFREQ_NAME_LEN)) {
|
|
|
|
*policy = CPUFREQ_POLICY_PERFORMANCE;
|
2006-07-07 03:30:26 +08:00
|
|
|
err = 0;
|
2006-10-26 18:50:58 +08:00
|
|
|
} else if (!strnicmp(str_governor, "powersave",
|
|
|
|
CPUFREQ_NAME_LEN)) {
|
2005-04-17 06:20:36 +08:00
|
|
|
*policy = CPUFREQ_POLICY_POWERSAVE;
|
2006-07-07 03:30:26 +08:00
|
|
|
err = 0;
|
2005-04-17 06:20:36 +08:00
|
|
|
}
|
2013-04-29 06:08:16 +08:00
|
|
|
} else if (cpufreq_driver->target) {
|
2005-04-17 06:20:36 +08:00
|
|
|
struct cpufreq_governor *t;
|
2006-07-07 03:30:26 +08:00
|
|
|
|
2006-01-14 07:54:22 +08:00
|
|
|
mutex_lock(&cpufreq_governor_mutex);
|
2006-07-07 03:30:26 +08:00
|
|
|
|
|
|
|
t = __find_governor(str_governor);
|
|
|
|
|
2006-07-07 03:32:01 +08:00
|
|
|
if (t == NULL) {
|
2011-05-04 23:38:56 +08:00
|
|
|
int ret;
|
2006-07-07 03:32:01 +08:00
|
|
|
|
2011-05-04 23:38:56 +08:00
|
|
|
mutex_unlock(&cpufreq_governor_mutex);
|
|
|
|
ret = request_module("cpufreq_%s", str_governor);
|
|
|
|
mutex_lock(&cpufreq_governor_mutex);
|
2006-07-07 03:32:01 +08:00
|
|
|
|
2011-05-04 23:38:56 +08:00
|
|
|
if (ret == 0)
|
|
|
|
t = __find_governor(str_governor);
|
2006-07-07 03:32:01 +08:00
|
|
|
}
|
|
|
|
|
2006-07-07 03:30:26 +08:00
|
|
|
if (t != NULL) {
|
|
|
|
*governor = t;
|
|
|
|
err = 0;
|
2005-04-17 06:20:36 +08:00
|
|
|
}
|
2006-07-07 03:30:26 +08:00
|
|
|
|
2006-01-14 07:54:22 +08:00
|
|
|
mutex_unlock(&cpufreq_governor_mutex);
|
2005-04-17 06:20:36 +08:00
|
|
|
}
|
2009-01-18 14:37:11 +08:00
|
|
|
out:
|
2006-07-07 03:30:26 +08:00
|
|
|
return err;
|
2005-04-17 06:20:36 +08:00
|
|
|
}
|
|
|
|
|
|
|
|
/**
|
2006-10-26 18:50:58 +08:00
|
|
|
* cpufreq_per_cpu_attr_read() / show_##file_name() -
|
|
|
|
* print out cpufreq information
|
2005-04-17 06:20:36 +08:00
|
|
|
*
|
|
|
|
* Write out information from cpufreq_driver->policy[cpu]; object must be
|
|
|
|
* "unsigned int".
|
|
|
|
*/
|
|
|
|
|
2006-02-28 13:43:23 +08:00
|
|
|
#define show_one(file_name, object) \
|
|
|
|
static ssize_t show_##file_name \
|
2008-03-06 03:28:32 +08:00
|
|
|
(struct cpufreq_policy *policy, char *buf) \
|
2006-02-28 13:43:23 +08:00
|
|
|
{ \
|
2009-01-18 14:37:11 +08:00
|
|
|
return sprintf(buf, "%u\n", policy->object); \
|
2005-04-17 06:20:36 +08:00
|
|
|
}
|
|
|
|
|
|
|
|
show_one(cpuinfo_min_freq, cpuinfo.min_freq);
|
|
|
|
show_one(cpuinfo_max_freq, cpuinfo.max_freq);
|
2009-02-04 08:17:41 +08:00
|
|
|
show_one(cpuinfo_transition_latency, cpuinfo.transition_latency);
|
2005-04-17 06:20:36 +08:00
|
|
|
show_one(scaling_min_freq, min);
|
|
|
|
show_one(scaling_max_freq, max);
|
|
|
|
show_one(scaling_cur_freq, cur);
|
|
|
|
|
2013-08-07 01:23:05 +08:00
|
|
|
static int __cpufreq_set_policy(struct cpufreq_policy *policy,
|
|
|
|
struct cpufreq_policy *new_policy);
|
2006-04-13 21:14:04 +08:00
|
|
|
|
2005-04-17 06:20:36 +08:00
|
|
|
/**
|
|
|
|
* cpufreq_per_cpu_attr_write() / store_##file_name() - sysfs write access
|
|
|
|
*/
|
|
|
|
#define store_one(file_name, object) \
|
|
|
|
static ssize_t store_##file_name \
|
2008-03-06 03:28:32 +08:00
|
|
|
(struct cpufreq_policy *policy, const char *buf, size_t count) \
|
2005-04-17 06:20:36 +08:00
|
|
|
{ \
|
2012-10-31 13:49:13 +08:00
|
|
|
unsigned int ret; \
|
2005-04-17 06:20:36 +08:00
|
|
|
struct cpufreq_policy new_policy; \
|
|
|
|
\
|
|
|
|
ret = cpufreq_get_policy(&new_policy, policy->cpu); \
|
|
|
|
if (ret) \
|
|
|
|
return -EINVAL; \
|
|
|
|
\
|
2009-01-18 14:37:11 +08:00
|
|
|
ret = sscanf(buf, "%u", &new_policy.object); \
|
2005-04-17 06:20:36 +08:00
|
|
|
if (ret != 1) \
|
|
|
|
return -EINVAL; \
|
|
|
|
\
|
2006-04-13 21:14:04 +08:00
|
|
|
ret = __cpufreq_set_policy(policy, &new_policy); \
|
|
|
|
policy->user_policy.object = policy->object; \
|
2005-04-17 06:20:36 +08:00
|
|
|
\
|
|
|
|
return ret ? ret : count; \
|
|
|
|
}
|
|
|
|
|
2009-01-18 14:37:11 +08:00
|
|
|
store_one(scaling_min_freq, min);
|
|
|
|
store_one(scaling_max_freq, max);
|
2005-04-17 06:20:36 +08:00
|
|
|
|
|
|
|
/**
|
|
|
|
* show_cpuinfo_cur_freq - current CPU frequency as detected by hardware
|
|
|
|
*/
|
2008-03-06 03:28:32 +08:00
|
|
|
static ssize_t show_cpuinfo_cur_freq(struct cpufreq_policy *policy,
|
|
|
|
char *buf)
|
2005-04-17 06:20:36 +08:00
|
|
|
{
|
2007-02-06 08:12:44 +08:00
|
|
|
unsigned int cur_freq = __cpufreq_get(policy->cpu);
|
2005-04-17 06:20:36 +08:00
|
|
|
if (!cur_freq)
|
|
|
|
return sprintf(buf, "<unknown>");
|
|
|
|
return sprintf(buf, "%u\n", cur_freq);
|
|
|
|
}
|
|
|
|
|
|
|
|
/**
|
|
|
|
* show_scaling_governor - show the current policy for the specified CPU
|
|
|
|
*/
|
2008-03-06 03:28:32 +08:00
|
|
|
static ssize_t show_scaling_governor(struct cpufreq_policy *policy, char *buf)
|
2005-04-17 06:20:36 +08:00
|
|
|
{
|
2009-01-18 14:37:11 +08:00
|
|
|
if (policy->policy == CPUFREQ_POLICY_POWERSAVE)
|
2005-04-17 06:20:36 +08:00
|
|
|
return sprintf(buf, "powersave\n");
|
|
|
|
else if (policy->policy == CPUFREQ_POLICY_PERFORMANCE)
|
|
|
|
return sprintf(buf, "performance\n");
|
|
|
|
else if (policy->governor)
|
2012-10-23 07:23:43 +08:00
|
|
|
return scnprintf(buf, CPUFREQ_NAME_PLEN, "%s\n",
|
2009-01-18 14:37:11 +08:00
|
|
|
policy->governor->name);
|
2005-04-17 06:20:36 +08:00
|
|
|
return -EINVAL;
|
|
|
|
}
|
|
|
|
|
|
|
|
/**
|
|
|
|
* store_scaling_governor - store policy for the specified CPU
|
|
|
|
*/
|
2008-03-06 03:28:32 +08:00
|
|
|
static ssize_t store_scaling_governor(struct cpufreq_policy *policy,
|
|
|
|
const char *buf, size_t count)
|
2005-04-17 06:20:36 +08:00
|
|
|
{
|
2012-10-31 13:49:13 +08:00
|
|
|
unsigned int ret;
|
2005-04-17 06:20:36 +08:00
|
|
|
char str_governor[16];
|
|
|
|
struct cpufreq_policy new_policy;
|
|
|
|
|
|
|
|
ret = cpufreq_get_policy(&new_policy, policy->cpu);
|
|
|
|
if (ret)
|
|
|
|
return ret;
|
|
|
|
|
2009-01-18 14:37:11 +08:00
|
|
|
ret = sscanf(buf, "%15s", str_governor);
|
2005-04-17 06:20:36 +08:00
|
|
|
if (ret != 1)
|
|
|
|
return -EINVAL;
|
|
|
|
|
2006-10-26 18:50:58 +08:00
|
|
|
if (cpufreq_parse_governor(str_governor, &new_policy.policy,
|
|
|
|
&new_policy.governor))
|
2005-04-17 06:20:36 +08:00
|
|
|
return -EINVAL;
|
|
|
|
|
2013-06-19 16:49:33 +08:00
|
|
|
/*
|
|
|
|
* Do not use cpufreq_set_policy here or the user_policy.max
|
|
|
|
* will be wrongly overridden
|
|
|
|
*/
|
2006-04-13 21:14:04 +08:00
|
|
|
ret = __cpufreq_set_policy(policy, &new_policy);
|
|
|
|
|
|
|
|
policy->user_policy.policy = policy->policy;
|
|
|
|
policy->user_policy.governor = policy->governor;
|
|
|
|
|
2006-10-26 18:50:58 +08:00
|
|
|
if (ret)
|
|
|
|
return ret;
|
|
|
|
else
|
|
|
|
return count;
|
2005-04-17 06:20:36 +08:00
|
|
|
}
|
|
|
|
|
|
|
|
/**
|
|
|
|
* show_scaling_driver - show the cpufreq driver currently loaded
|
|
|
|
*/
|
2008-03-06 03:28:32 +08:00
|
|
|
static ssize_t show_scaling_driver(struct cpufreq_policy *policy, char *buf)
|
2005-04-17 06:20:36 +08:00
|
|
|
{
|
2013-04-29 06:08:16 +08:00
|
|
|
return scnprintf(buf, CPUFREQ_NAME_PLEN, "%s\n", cpufreq_driver->name);
|
2005-04-17 06:20:36 +08:00
|
|
|
}
|
|
|
|
|
|
|
|
/**
|
|
|
|
* show_scaling_available_governors - show the available CPUfreq governors
|
|
|
|
*/
|
2008-03-06 03:28:32 +08:00
|
|
|
static ssize_t show_scaling_available_governors(struct cpufreq_policy *policy,
|
|
|
|
char *buf)
|
2005-04-17 06:20:36 +08:00
|
|
|
{
|
|
|
|
ssize_t i = 0;
|
|
|
|
struct cpufreq_governor *t;
|
|
|
|
|
2013-04-29 06:08:16 +08:00
|
|
|
if (!cpufreq_driver->target) {
|
2005-04-17 06:20:36 +08:00
|
|
|
i += sprintf(buf, "performance powersave");
|
|
|
|
goto out;
|
|
|
|
}
|
|
|
|
|
|
|
|
list_for_each_entry(t, &cpufreq_governor_list, governor_list) {
|
2009-01-18 14:37:11 +08:00
|
|
|
if (i >= (ssize_t) ((PAGE_SIZE / sizeof(char))
|
|
|
|
- (CPUFREQ_NAME_LEN + 2)))
|
2005-04-17 06:20:36 +08:00
|
|
|
goto out;
|
2012-10-23 07:23:43 +08:00
|
|
|
i += scnprintf(&buf[i], CPUFREQ_NAME_PLEN, "%s ", t->name);
|
2005-04-17 06:20:36 +08:00
|
|
|
}
|
2006-02-03 06:03:42 +08:00
|
|
|
out:
|
2005-04-17 06:20:36 +08:00
|
|
|
i += sprintf(&buf[i], "\n");
|
|
|
|
return i;
|
|
|
|
}
|
2008-04-19 04:31:12 +08:00
|
|
|
|
2013-06-27 15:08:54 +08:00
|
|
|
ssize_t cpufreq_show_cpus(const struct cpumask *mask, char *buf)
|
2005-04-17 06:20:36 +08:00
|
|
|
{
|
|
|
|
ssize_t i = 0;
|
|
|
|
unsigned int cpu;
|
|
|
|
|
2009-01-04 21:18:06 +08:00
|
|
|
for_each_cpu(cpu, mask) {
|
2005-04-17 06:20:36 +08:00
|
|
|
if (i)
|
|
|
|
i += scnprintf(&buf[i], (PAGE_SIZE - i - 2), " ");
|
|
|
|
i += scnprintf(&buf[i], (PAGE_SIZE - i - 2), "%u", cpu);
|
|
|
|
if (i >= (PAGE_SIZE - 5))
|
2009-01-18 14:37:11 +08:00
|
|
|
break;
|
2005-04-17 06:20:36 +08:00
|
|
|
}
|
|
|
|
i += sprintf(&buf[i], "\n");
|
|
|
|
return i;
|
|
|
|
}
|
2013-06-27 15:08:54 +08:00
|
|
|
EXPORT_SYMBOL_GPL(cpufreq_show_cpus);
|
2005-04-17 06:20:36 +08:00
|
|
|
|
2008-04-19 04:31:12 +08:00
|
|
|
/**
|
|
|
|
* show_related_cpus - show the CPUs affected by each transition even if
|
|
|
|
* hw coordination is in use
|
|
|
|
*/
|
|
|
|
static ssize_t show_related_cpus(struct cpufreq_policy *policy, char *buf)
|
|
|
|
{
|
2013-06-27 15:08:54 +08:00
|
|
|
return cpufreq_show_cpus(policy->related_cpus, buf);
|
2008-04-19 04:31:12 +08:00
|
|
|
}
|
|
|
|
|
|
|
|
/**
|
|
|
|
* show_affected_cpus - show the CPUs affected by each transition
|
|
|
|
*/
|
|
|
|
static ssize_t show_affected_cpus(struct cpufreq_policy *policy, char *buf)
|
|
|
|
{
|
2013-06-27 15:08:54 +08:00
|
|
|
return cpufreq_show_cpus(policy->cpus, buf);
|
2008-04-19 04:31:12 +08:00
|
|
|
}
|
|
|
|
|
2007-10-27 01:18:21 +08:00
|
|
|
static ssize_t store_scaling_setspeed(struct cpufreq_policy *policy,
|
2008-03-06 03:28:32 +08:00
|
|
|
const char *buf, size_t count)
|
2007-10-27 01:18:21 +08:00
|
|
|
{
|
|
|
|
unsigned int freq = 0;
|
|
|
|
unsigned int ret;
|
|
|
|
|
2008-06-06 13:46:33 +08:00
|
|
|
if (!policy->governor || !policy->governor->store_setspeed)
|
2007-10-27 01:18:21 +08:00
|
|
|
return -EINVAL;
|
|
|
|
|
|
|
|
ret = sscanf(buf, "%u", &freq);
|
|
|
|
if (ret != 1)
|
|
|
|
return -EINVAL;
|
|
|
|
|
|
|
|
policy->governor->store_setspeed(policy, freq);
|
|
|
|
|
|
|
|
return count;
|
|
|
|
}
|
|
|
|
|
|
|
|
static ssize_t show_scaling_setspeed(struct cpufreq_policy *policy, char *buf)
|
|
|
|
{
|
2008-06-06 13:46:33 +08:00
|
|
|
if (!policy->governor || !policy->governor->show_setspeed)
|
2007-10-27 01:18:21 +08:00
|
|
|
return sprintf(buf, "<unsupported>\n");
|
|
|
|
|
|
|
|
return policy->governor->show_setspeed(policy, buf);
|
|
|
|
}
|
2005-04-17 06:20:36 +08:00
|
|
|
|
2009-11-19 19:31:01 +08:00
|
|
|
/**
|
2012-10-23 07:23:33 +08:00
|
|
|
* show_bios_limit - show the current cpufreq HW/BIOS limitation
|
2009-11-19 19:31:01 +08:00
|
|
|
*/
|
|
|
|
static ssize_t show_bios_limit(struct cpufreq_policy *policy, char *buf)
|
|
|
|
{
|
|
|
|
unsigned int limit;
|
|
|
|
int ret;
|
2013-04-29 06:08:16 +08:00
|
|
|
if (cpufreq_driver->bios_limit) {
|
|
|
|
ret = cpufreq_driver->bios_limit(policy->cpu, &limit);
|
2009-11-19 19:31:01 +08:00
|
|
|
if (!ret)
|
|
|
|
return sprintf(buf, "%u\n", limit);
|
|
|
|
}
|
|
|
|
return sprintf(buf, "%u\n", policy->cpuinfo.max_freq);
|
|
|
|
}
|
|
|
|
|
2010-04-01 03:56:46 +08:00
|
|
|
cpufreq_freq_attr_ro_perm(cpuinfo_cur_freq, 0400);
|
|
|
|
cpufreq_freq_attr_ro(cpuinfo_min_freq);
|
|
|
|
cpufreq_freq_attr_ro(cpuinfo_max_freq);
|
|
|
|
cpufreq_freq_attr_ro(cpuinfo_transition_latency);
|
|
|
|
cpufreq_freq_attr_ro(scaling_available_governors);
|
|
|
|
cpufreq_freq_attr_ro(scaling_driver);
|
|
|
|
cpufreq_freq_attr_ro(scaling_cur_freq);
|
|
|
|
cpufreq_freq_attr_ro(bios_limit);
|
|
|
|
cpufreq_freq_attr_ro(related_cpus);
|
|
|
|
cpufreq_freq_attr_ro(affected_cpus);
|
|
|
|
cpufreq_freq_attr_rw(scaling_min_freq);
|
|
|
|
cpufreq_freq_attr_rw(scaling_max_freq);
|
|
|
|
cpufreq_freq_attr_rw(scaling_governor);
|
|
|
|
cpufreq_freq_attr_rw(scaling_setspeed);
|
2005-04-17 06:20:36 +08:00
|
|
|
|
2008-03-06 03:28:32 +08:00
|
|
|
static struct attribute *default_attrs[] = {
|
2005-04-17 06:20:36 +08:00
|
|
|
&cpuinfo_min_freq.attr,
|
|
|
|
&cpuinfo_max_freq.attr,
|
2009-02-04 08:17:41 +08:00
|
|
|
&cpuinfo_transition_latency.attr,
|
2005-04-17 06:20:36 +08:00
|
|
|
&scaling_min_freq.attr,
|
|
|
|
&scaling_max_freq.attr,
|
|
|
|
&affected_cpus.attr,
|
2008-04-19 04:31:12 +08:00
|
|
|
&related_cpus.attr,
|
2005-04-17 06:20:36 +08:00
|
|
|
&scaling_governor.attr,
|
|
|
|
&scaling_driver.attr,
|
|
|
|
&scaling_available_governors.attr,
|
2007-10-27 01:18:21 +08:00
|
|
|
&scaling_setspeed.attr,
|
2005-04-17 06:20:36 +08:00
|
|
|
NULL
|
|
|
|
};
|
|
|
|
|
2009-01-18 14:37:11 +08:00
|
|
|
#define to_policy(k) container_of(k, struct cpufreq_policy, kobj)
|
|
|
|
#define to_attr(a) container_of(a, struct freq_attr, attr)
|
2005-04-17 06:20:36 +08:00
|
|
|
|
2009-01-18 14:37:11 +08:00
|
|
|
static ssize_t show(struct kobject *kobj, struct attribute *attr, char *buf)
|
2005-04-17 06:20:36 +08:00
|
|
|
{
|
2008-03-06 03:28:32 +08:00
|
|
|
struct cpufreq_policy *policy = to_policy(kobj);
|
|
|
|
struct freq_attr *fattr = to_attr(attr);
|
2008-03-06 03:20:57 +08:00
|
|
|
ssize_t ret = -EINVAL;
|
2012-07-21 02:14:38 +08:00
|
|
|
policy = cpufreq_cpu_get_sysfs(policy->cpu);
|
2005-04-17 06:20:36 +08:00
|
|
|
if (!policy)
|
2008-03-06 03:20:57 +08:00
|
|
|
goto no_policy;
|
2007-02-06 08:12:44 +08:00
|
|
|
|
|
|
|
if (lock_policy_rwsem_read(policy->cpu) < 0)
|
2008-03-06 03:20:57 +08:00
|
|
|
goto fail;
|
2007-02-06 08:12:44 +08:00
|
|
|
|
2006-10-26 18:50:58 +08:00
|
|
|
if (fattr->show)
|
|
|
|
ret = fattr->show(policy, buf);
|
|
|
|
else
|
|
|
|
ret = -EIO;
|
|
|
|
|
2007-02-06 08:12:44 +08:00
|
|
|
unlock_policy_rwsem_read(policy->cpu);
|
2008-03-06 03:20:57 +08:00
|
|
|
fail:
|
2012-07-21 02:14:38 +08:00
|
|
|
cpufreq_cpu_put_sysfs(policy);
|
2008-03-06 03:20:57 +08:00
|
|
|
no_policy:
|
2005-04-17 06:20:36 +08:00
|
|
|
return ret;
|
|
|
|
}
|
|
|
|
|
2008-03-06 03:28:32 +08:00
|
|
|
static ssize_t store(struct kobject *kobj, struct attribute *attr,
|
|
|
|
const char *buf, size_t count)
|
2005-04-17 06:20:36 +08:00
|
|
|
{
|
2008-03-06 03:28:32 +08:00
|
|
|
struct cpufreq_policy *policy = to_policy(kobj);
|
|
|
|
struct freq_attr *fattr = to_attr(attr);
|
2008-03-06 03:22:25 +08:00
|
|
|
ssize_t ret = -EINVAL;
|
2012-07-21 02:14:38 +08:00
|
|
|
policy = cpufreq_cpu_get_sysfs(policy->cpu);
|
2005-04-17 06:20:36 +08:00
|
|
|
if (!policy)
|
2008-03-06 03:22:25 +08:00
|
|
|
goto no_policy;
|
2007-02-06 08:12:44 +08:00
|
|
|
|
|
|
|
if (lock_policy_rwsem_write(policy->cpu) < 0)
|
2008-03-06 03:22:25 +08:00
|
|
|
goto fail;
|
2007-02-06 08:12:44 +08:00
|
|
|
|
2006-10-26 18:50:58 +08:00
|
|
|
if (fattr->store)
|
|
|
|
ret = fattr->store(policy, buf, count);
|
|
|
|
else
|
|
|
|
ret = -EIO;
|
|
|
|
|
2007-02-06 08:12:44 +08:00
|
|
|
unlock_policy_rwsem_write(policy->cpu);
|
2008-03-06 03:22:25 +08:00
|
|
|
fail:
|
2012-07-21 02:14:38 +08:00
|
|
|
cpufreq_cpu_put_sysfs(policy);
|
2008-03-06 03:22:25 +08:00
|
|
|
no_policy:
|
2005-04-17 06:20:36 +08:00
|
|
|
return ret;
|
|
|
|
}
|
|
|
|
|
2008-03-06 03:28:32 +08:00
|
|
|
static void cpufreq_sysfs_release(struct kobject *kobj)
|
2005-04-17 06:20:36 +08:00
|
|
|
{
|
2008-03-06 03:28:32 +08:00
|
|
|
struct cpufreq_policy *policy = to_policy(kobj);
|
2011-03-27 21:04:46 +08:00
|
|
|
pr_debug("last reference is dropped\n");
|
2005-04-17 06:20:36 +08:00
|
|
|
complete(&policy->kobj_unregister);
|
|
|
|
}
|
|
|
|
|
2010-01-19 09:58:23 +08:00
|
|
|
static const struct sysfs_ops sysfs_ops = {
|
2005-04-17 06:20:36 +08:00
|
|
|
.show = show,
|
|
|
|
.store = store,
|
|
|
|
};
|
|
|
|
|
|
|
|
static struct kobj_type ktype_cpufreq = {
|
|
|
|
.sysfs_ops = &sysfs_ops,
|
|
|
|
.default_attrs = default_attrs,
|
|
|
|
.release = cpufreq_sysfs_release,
|
|
|
|
};
|
|
|
|
|
2013-05-17 18:39:09 +08:00
|
|
|
struct kobject *cpufreq_global_kobject;
|
|
|
|
EXPORT_SYMBOL(cpufreq_global_kobject);
|
|
|
|
|
|
|
|
static int cpufreq_global_kobject_usage;
|
|
|
|
|
|
|
|
int cpufreq_get_global_kobject(void)
|
|
|
|
{
|
|
|
|
if (!cpufreq_global_kobject_usage++)
|
|
|
|
return kobject_add(cpufreq_global_kobject,
|
|
|
|
&cpu_subsys.dev_root->kobj, "%s", "cpufreq");
|
|
|
|
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
EXPORT_SYMBOL(cpufreq_get_global_kobject);
|
|
|
|
|
|
|
|
void cpufreq_put_global_kobject(void)
|
|
|
|
{
|
|
|
|
if (!--cpufreq_global_kobject_usage)
|
|
|
|
kobject_del(cpufreq_global_kobject);
|
|
|
|
}
|
|
|
|
EXPORT_SYMBOL(cpufreq_put_global_kobject);
|
|
|
|
|
|
|
|
int cpufreq_sysfs_create_file(const struct attribute *attr)
|
|
|
|
{
|
|
|
|
int ret = cpufreq_get_global_kobject();
|
|
|
|
|
|
|
|
if (!ret) {
|
|
|
|
ret = sysfs_create_file(cpufreq_global_kobject, attr);
|
|
|
|
if (ret)
|
|
|
|
cpufreq_put_global_kobject();
|
|
|
|
}
|
|
|
|
|
|
|
|
return ret;
|
|
|
|
}
|
|
|
|
EXPORT_SYMBOL(cpufreq_sysfs_create_file);
|
|
|
|
|
|
|
|
void cpufreq_sysfs_remove_file(const struct attribute *attr)
|
|
|
|
{
|
|
|
|
sysfs_remove_file(cpufreq_global_kobject, attr);
|
|
|
|
cpufreq_put_global_kobject();
|
|
|
|
}
|
|
|
|
EXPORT_SYMBOL(cpufreq_sysfs_remove_file);
|
|
|
|
|
2009-07-09 05:35:39 +08:00
|
|
|
/* symlink affected CPUs */
|
2013-07-31 20:35:14 +08:00
|
|
|
static int cpufreq_add_dev_symlink(struct cpufreq_policy *policy)
|
2009-07-09 05:35:39 +08:00
|
|
|
{
|
|
|
|
unsigned int j;
|
|
|
|
int ret = 0;
|
|
|
|
|
|
|
|
for_each_cpu(j, policy->cpus) {
|
2011-12-22 06:29:42 +08:00
|
|
|
struct device *cpu_dev;
|
2009-07-09 05:35:39 +08:00
|
|
|
|
2013-07-31 20:35:14 +08:00
|
|
|
if (j == policy->cpu)
|
2009-07-09 05:35:39 +08:00
|
|
|
continue;
|
|
|
|
|
2013-07-31 20:31:33 +08:00
|
|
|
pr_debug("Adding link for CPU: %u\n", j);
|
2011-12-22 06:29:42 +08:00
|
|
|
cpu_dev = get_cpu_device(j);
|
|
|
|
ret = sysfs_create_link(&cpu_dev->kobj, &policy->kobj,
|
2009-07-09 05:35:39 +08:00
|
|
|
"cpufreq");
|
cpufreq: Do not hold driver module references for additional policy CPUs
The cpufreq core is a little inconsistent in the way it uses the
driver module refcount.
Namely, if __cpufreq_add_dev() is called for a CPU that doesn't
share the policy object with any other CPUs, the driver module
refcount it grabs to start with will be dropped by it before
returning and will be equal to whatever it had been before that
function was invoked.
However, if the given CPU does share the policy object with other
CPUs, either cpufreq_add_policy_cpu() is called to link the new CPU
to the existing policy, or cpufreq_add_dev_symlink() is used to link
the other CPUs sharing the policy with it to the just created policy
object. In that case, because both cpufreq_add_policy_cpu() and
cpufreq_add_dev_symlink() call cpufreq_cpu_get() for the given
policy (the latter possibly many times) without the balancing
cpufreq_cpu_put() (unless there is an error), the driver module
refcount will be left by __cpufreq_add_dev() with a nonzero value
(different from the initial one).
To remove that inconsistency make cpufreq_add_policy_cpu() execute
cpufreq_cpu_put() for the given policy before returning, which
decrements the driver module refcount so that it will be equal to its
initial value after __cpufreq_add_dev() returns. Also remove the
cpufreq_cpu_get() call from cpufreq_add_dev_symlink(), since both the
policy refcount and the driver module refcount are nonzero when it is
called and they don't need to be bumped up by it.
Accordingly, drop the cpufreq_cpu_put() from __cpufreq_remove_dev(),
since it is only necessary to balance the cpufreq_cpu_get() called
by cpufreq_add_policy_cpu() or cpufreq_add_dev_symlink().
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
2013-08-04 07:19:34 +08:00
|
|
|
if (ret)
|
|
|
|
break;
|
2009-07-09 05:35:39 +08:00
|
|
|
}
|
|
|
|
return ret;
|
|
|
|
}
|
|
|
|
|
2013-07-31 20:35:14 +08:00
|
|
|
static int cpufreq_add_dev_interface(struct cpufreq_policy *policy,
|
2011-12-22 06:29:42 +08:00
|
|
|
struct device *dev)
|
2009-07-09 06:05:42 +08:00
|
|
|
{
|
|
|
|
struct freq_attr **drv_attr;
|
|
|
|
int ret = 0;
|
|
|
|
|
|
|
|
/* prepare interface data */
|
|
|
|
ret = kobject_init_and_add(&policy->kobj, &ktype_cpufreq,
|
2011-12-22 06:29:42 +08:00
|
|
|
&dev->kobj, "cpufreq");
|
2009-07-09 06:05:42 +08:00
|
|
|
if (ret)
|
|
|
|
return ret;
|
|
|
|
|
|
|
|
/* set up files for this cpu device */
|
2013-04-29 06:08:16 +08:00
|
|
|
drv_attr = cpufreq_driver->attr;
|
2009-07-09 06:05:42 +08:00
|
|
|
while ((drv_attr) && (*drv_attr)) {
|
|
|
|
ret = sysfs_create_file(&policy->kobj, &((*drv_attr)->attr));
|
|
|
|
if (ret)
|
2013-04-29 06:08:16 +08:00
|
|
|
goto err_out_kobj_put;
|
2009-07-09 06:05:42 +08:00
|
|
|
drv_attr++;
|
|
|
|
}
|
2013-04-29 06:08:16 +08:00
|
|
|
if (cpufreq_driver->get) {
|
2009-07-09 06:05:42 +08:00
|
|
|
ret = sysfs_create_file(&policy->kobj, &cpuinfo_cur_freq.attr);
|
|
|
|
if (ret)
|
2013-04-29 06:08:16 +08:00
|
|
|
goto err_out_kobj_put;
|
2009-07-09 06:05:42 +08:00
|
|
|
}
|
2013-04-29 06:08:16 +08:00
|
|
|
if (cpufreq_driver->target) {
|
2009-07-09 06:05:42 +08:00
|
|
|
ret = sysfs_create_file(&policy->kobj, &scaling_cur_freq.attr);
|
|
|
|
if (ret)
|
2013-04-29 06:08:16 +08:00
|
|
|
goto err_out_kobj_put;
|
2009-07-09 06:05:42 +08:00
|
|
|
}
|
2013-04-29 06:08:16 +08:00
|
|
|
if (cpufreq_driver->bios_limit) {
|
2009-11-19 19:31:01 +08:00
|
|
|
ret = sysfs_create_file(&policy->kobj, &bios_limit.attr);
|
|
|
|
if (ret)
|
2013-04-29 06:08:16 +08:00
|
|
|
goto err_out_kobj_put;
|
2009-11-19 19:31:01 +08:00
|
|
|
}
|
2009-07-09 06:05:42 +08:00
|
|
|
|
2013-07-31 20:35:14 +08:00
|
|
|
ret = cpufreq_add_dev_symlink(policy);
|
2009-07-09 06:48:47 +08:00
|
|
|
if (ret)
|
|
|
|
goto err_out_kobj_put;
|
|
|
|
|
2013-07-30 06:54:23 +08:00
|
|
|
return ret;
|
|
|
|
|
|
|
|
err_out_kobj_put:
|
|
|
|
kobject_put(&policy->kobj);
|
|
|
|
wait_for_completion(&policy->kobj_unregister);
|
|
|
|
return ret;
|
|
|
|
}
|
|
|
|
|
|
|
|
static void cpufreq_init_policy(struct cpufreq_policy *policy)
|
|
|
|
{
|
|
|
|
struct cpufreq_policy new_policy;
|
|
|
|
int ret = 0;
|
|
|
|
|
2013-08-07 01:23:06 +08:00
|
|
|
memcpy(&new_policy, policy, sizeof(*policy));
|
2009-07-09 06:48:47 +08:00
|
|
|
/* assure that the starting sequence is run in __cpufreq_set_policy */
|
|
|
|
policy->governor = NULL;
|
|
|
|
|
|
|
|
/* set default policy */
|
|
|
|
ret = __cpufreq_set_policy(policy, &new_policy);
|
|
|
|
policy->user_policy.policy = policy->policy;
|
|
|
|
policy->user_policy.governor = policy->governor;
|
|
|
|
|
|
|
|
if (ret) {
|
2011-03-27 21:04:46 +08:00
|
|
|
pr_debug("setting policy failed\n");
|
2013-04-29 06:08:16 +08:00
|
|
|
if (cpufreq_driver->exit)
|
|
|
|
cpufreq_driver->exit(policy);
|
2009-07-09 06:48:47 +08:00
|
|
|
}
|
2009-07-09 06:05:42 +08:00
|
|
|
}
|
|
|
|
|
2013-01-29 22:39:08 +08:00
|
|
|
#ifdef CONFIG_HOTPLUG_CPU
|
2013-08-04 07:20:07 +08:00
|
|
|
static int cpufreq_add_policy_cpu(struct cpufreq_policy *policy,
|
|
|
|
unsigned int cpu, struct device *dev,
|
|
|
|
bool frozen)
|
2013-01-29 22:39:08 +08:00
|
|
|
{
|
2013-04-29 06:08:16 +08:00
|
|
|
int ret = 0, has_target = !!cpufreq_driver->target;
|
2013-01-29 22:39:08 +08:00
|
|
|
unsigned long flags;
|
|
|
|
|
2013-04-22 06:48:03 +08:00
|
|
|
if (has_target)
|
|
|
|
__cpufreq_governor(policy, CPUFREQ_GOV_STOP);
|
2013-01-29 22:39:08 +08:00
|
|
|
|
2013-08-04 07:20:07 +08:00
|
|
|
lock_policy_rwsem_write(policy->cpu);
|
2013-02-07 13:25:00 +08:00
|
|
|
|
2013-02-23 00:24:34 +08:00
|
|
|
write_lock_irqsave(&cpufreq_driver_lock, flags);
|
2013-02-07 13:25:00 +08:00
|
|
|
|
2013-01-29 22:39:08 +08:00
|
|
|
cpumask_set_cpu(cpu, policy->cpus);
|
2013-02-07 13:25:00 +08:00
|
|
|
per_cpu(cpufreq_policy_cpu, cpu) = policy->cpu;
|
2013-01-29 22:39:08 +08:00
|
|
|
per_cpu(cpufreq_cpu_data, cpu) = policy;
|
2013-02-23 00:24:34 +08:00
|
|
|
write_unlock_irqrestore(&cpufreq_driver_lock, flags);
|
2013-01-29 22:39:08 +08:00
|
|
|
|
2013-08-04 07:20:07 +08:00
|
|
|
unlock_policy_rwsem_write(policy->cpu);
|
2013-02-07 13:25:00 +08:00
|
|
|
|
2013-04-22 06:48:03 +08:00
|
|
|
if (has_target) {
|
|
|
|
__cpufreq_governor(policy, CPUFREQ_GOV_START);
|
|
|
|
__cpufreq_governor(policy, CPUFREQ_GOV_LIMITS);
|
|
|
|
}
|
2013-01-29 22:39:08 +08:00
|
|
|
|
2013-07-30 06:54:49 +08:00
|
|
|
/* Don't touch sysfs links during light-weight init */
|
cpufreq: Do not hold driver module references for additional policy CPUs
The cpufreq core is a little inconsistent in the way it uses the
driver module refcount.
Namely, if __cpufreq_add_dev() is called for a CPU that doesn't
share the policy object with any other CPUs, the driver module
refcount it grabs to start with will be dropped by it before
returning and will be equal to whatever it had been before that
function was invoked.
However, if the given CPU does share the policy object with other
CPUs, either cpufreq_add_policy_cpu() is called to link the new CPU
to the existing policy, or cpufreq_add_dev_symlink() is used to link
the other CPUs sharing the policy with it to the just created policy
object. In that case, because both cpufreq_add_policy_cpu() and
cpufreq_add_dev_symlink() call cpufreq_cpu_get() for the given
policy (the latter possibly many times) without the balancing
cpufreq_cpu_put() (unless there is an error), the driver module
refcount will be left by __cpufreq_add_dev() with a nonzero value
(different from the initial one).
To remove that inconsistency make cpufreq_add_policy_cpu() execute
cpufreq_cpu_put() for the given policy before returning, which
decrements the driver module refcount so that it will be equal to its
initial value after __cpufreq_add_dev() returns. Also remove the
cpufreq_cpu_get() call from cpufreq_add_dev_symlink(), since both the
policy refcount and the driver module refcount are nonzero when it is
called and they don't need to be bumped up by it.
Accordingly, drop the cpufreq_cpu_put() from __cpufreq_remove_dev(),
since it is only necessary to balance the cpufreq_cpu_get() called
by cpufreq_add_policy_cpu() or cpufreq_add_dev_symlink().
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
2013-08-04 07:19:34 +08:00
|
|
|
if (!frozen)
|
|
|
|
ret = sysfs_create_link(&dev->kobj, &policy->kobj, "cpufreq");
|
2013-07-30 06:54:49 +08:00
|
|
|
|
|
|
|
return ret;
|
2013-01-29 22:39:08 +08:00
|
|
|
}
|
|
|
|
#endif
|
2005-04-17 06:20:36 +08:00
|
|
|
|
cpufreq: Preserve policy structure across suspend/resume
To perform light-weight cpu-init and teardown in the cpufreq subsystem
during suspend/resume, we need to separate out the 2 main functionalities
of the cpufreq CPU hotplug callbacks, as outlined below:
1. Init/tear-down of core cpufreq and CPU-specific components, which are
critical to the correct functioning of the cpufreq subsystem.
2. Init/tear-down of cpufreq sysfs files during suspend/resume.
The first part requires accurate updates to the policy structure such as
its ->cpus and ->related_cpus masks, whereas the second part requires that
the policy->kobj structure is not released or re-initialized during
suspend/resume.
To handle both these requirements, we need to allow updates to the policy
structure throughout suspend/resume, but prevent the structure from getting
freed up. Also, we must have a mechanism by which the cpu-up callbacks can
restore the policy structure, without allocating things afresh. (That also
helps avoid memory leaks).
To achieve this, we use 2 schemes:
a. Use a fallback per-cpu storage area for preserving the policy structures
during suspend, so that they can be restored during resume appropriately.
b. Use the 'frozen' flag to determine when to free or allocate the policy
structure vs when to restore the policy from the saved fallback storage.
Thus we can successfully preserve the structure across suspend/resume.
Effectively, this helps us complete the separation of the 'light-weight'
and the 'full' init/tear-down sequences in the cpufreq subsystem, so that
this can be made use of in the suspend/resume scenario.
Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2013-07-30 06:55:10 +08:00
|
|
|
static struct cpufreq_policy *cpufreq_policy_restore(unsigned int cpu)
|
|
|
|
{
|
|
|
|
struct cpufreq_policy *policy;
|
|
|
|
unsigned long flags;
|
|
|
|
|
|
|
|
write_lock_irqsave(&cpufreq_driver_lock, flags);
|
|
|
|
|
|
|
|
policy = per_cpu(cpufreq_cpu_data_fallback, cpu);
|
|
|
|
|
|
|
|
write_unlock_irqrestore(&cpufreq_driver_lock, flags);
|
|
|
|
|
|
|
|
return policy;
|
|
|
|
}
|
|
|
|
|
2013-07-30 06:54:11 +08:00
|
|
|
static struct cpufreq_policy *cpufreq_policy_alloc(void)
|
|
|
|
{
|
|
|
|
struct cpufreq_policy *policy;
|
|
|
|
|
|
|
|
policy = kzalloc(sizeof(*policy), GFP_KERNEL);
|
|
|
|
if (!policy)
|
|
|
|
return NULL;
|
|
|
|
|
|
|
|
if (!alloc_cpumask_var(&policy->cpus, GFP_KERNEL))
|
|
|
|
goto err_free_policy;
|
|
|
|
|
|
|
|
if (!zalloc_cpumask_var(&policy->related_cpus, GFP_KERNEL))
|
|
|
|
goto err_free_cpumask;
|
|
|
|
|
2013-08-07 01:23:08 +08:00
|
|
|
INIT_LIST_HEAD(&policy->policy_list);
|
2013-07-30 06:54:11 +08:00
|
|
|
return policy;
|
|
|
|
|
|
|
|
err_free_cpumask:
|
|
|
|
free_cpumask_var(policy->cpus);
|
|
|
|
err_free_policy:
|
|
|
|
kfree(policy);
|
|
|
|
|
|
|
|
return NULL;
|
|
|
|
}
|
|
|
|
|
|
|
|
static void cpufreq_policy_free(struct cpufreq_policy *policy)
|
|
|
|
{
|
2013-08-07 01:23:08 +08:00
|
|
|
unsigned long flags;
|
|
|
|
|
|
|
|
write_lock_irqsave(&cpufreq_driver_lock, flags);
|
|
|
|
list_del(&policy->policy_list);
|
|
|
|
write_unlock_irqrestore(&cpufreq_driver_lock, flags);
|
|
|
|
|
2013-07-30 06:54:11 +08:00
|
|
|
free_cpumask_var(policy->related_cpus);
|
|
|
|
free_cpumask_var(policy->cpus);
|
|
|
|
kfree(policy);
|
|
|
|
}
|
|
|
|
|
2013-07-30 06:54:49 +08:00
|
|
|
static int __cpufreq_add_dev(struct device *dev, struct subsys_interface *sif,
|
|
|
|
bool frozen)
|
2005-04-17 06:20:36 +08:00
|
|
|
{
|
2013-01-29 22:39:08 +08:00
|
|
|
unsigned int j, cpu = dev->id;
|
2013-02-07 13:26:03 +08:00
|
|
|
int ret = -ENOMEM;
|
2005-04-17 06:20:36 +08:00
|
|
|
struct cpufreq_policy *policy;
|
|
|
|
unsigned long flags;
|
2009-11-12 22:18:46 +08:00
|
|
|
#ifdef CONFIG_HOTPLUG_CPU
|
2013-08-07 01:23:09 +08:00
|
|
|
struct cpufreq_policy *tpolicy;
|
2013-01-29 22:39:08 +08:00
|
|
|
struct cpufreq_governor *gov;
|
2009-11-12 22:18:46 +08:00
|
|
|
#endif
|
2005-04-17 06:20:36 +08:00
|
|
|
|
2005-10-31 06:59:54 +08:00
|
|
|
if (cpu_is_offline(cpu))
|
|
|
|
return 0;
|
|
|
|
|
2011-03-27 21:04:46 +08:00
|
|
|
pr_debug("adding CPU %u\n", cpu);
|
2005-04-17 06:20:36 +08:00
|
|
|
|
|
|
|
#ifdef CONFIG_SMP
|
|
|
|
/* check whether a different CPU already registered this
|
|
|
|
* CPU because it is in the same boat. */
|
|
|
|
policy = cpufreq_cpu_get(cpu);
|
|
|
|
if (unlikely(policy)) {
|
2006-03-05 16:37:23 +08:00
|
|
|
cpufreq_cpu_put(policy);
|
2005-04-17 06:20:36 +08:00
|
|
|
return 0;
|
|
|
|
}
|
2013-01-29 22:39:08 +08:00
|
|
|
|
|
|
|
#ifdef CONFIG_HOTPLUG_CPU
|
|
|
|
/* Check if this cpu was hot-unplugged earlier and has siblings */
|
2013-02-23 00:24:34 +08:00
|
|
|
read_lock_irqsave(&cpufreq_driver_lock, flags);
|
2013-08-07 01:23:09 +08:00
|
|
|
list_for_each_entry(tpolicy, &cpufreq_policy_list, policy_list) {
|
|
|
|
if (cpumask_test_cpu(cpu, tpolicy->related_cpus)) {
|
2013-02-23 00:24:34 +08:00
|
|
|
read_unlock_irqrestore(&cpufreq_driver_lock, flags);
|
2013-08-07 01:23:09 +08:00
|
|
|
return cpufreq_add_policy_cpu(tpolicy, cpu, dev,
|
|
|
|
frozen);
|
2013-02-07 13:25:00 +08:00
|
|
|
}
|
2013-01-29 22:39:08 +08:00
|
|
|
}
|
2013-02-23 00:24:34 +08:00
|
|
|
read_unlock_irqrestore(&cpufreq_driver_lock, flags);
|
2013-01-29 22:39:08 +08:00
|
|
|
#endif
|
2005-04-17 06:20:36 +08:00
|
|
|
#endif
|
|
|
|
|
2013-04-29 06:08:16 +08:00
|
|
|
if (!try_module_get(cpufreq_driver->owner)) {
|
2005-04-17 06:20:36 +08:00
|
|
|
ret = -EINVAL;
|
|
|
|
goto module_out;
|
|
|
|
}
|
|
|
|
|
cpufreq: Preserve policy structure across suspend/resume
To perform light-weight cpu-init and teardown in the cpufreq subsystem
during suspend/resume, we need to separate out the 2 main functionalities
of the cpufreq CPU hotplug callbacks, as outlined below:
1. Init/tear-down of core cpufreq and CPU-specific components, which are
critical to the correct functioning of the cpufreq subsystem.
2. Init/tear-down of cpufreq sysfs files during suspend/resume.
The first part requires accurate updates to the policy structure such as
its ->cpus and ->related_cpus masks, whereas the second part requires that
the policy->kobj structure is not released or re-initialized during
suspend/resume.
To handle both these requirements, we need to allow updates to the policy
structure throughout suspend/resume, but prevent the structure from getting
freed up. Also, we must have a mechanism by which the cpu-up callbacks can
restore the policy structure, without allocating things afresh. (That also
helps avoid memory leaks).
To achieve this, we use 2 schemes:
a. Use a fallback per-cpu storage area for preserving the policy structures
during suspend, so that they can be restored during resume appropriately.
b. Use the 'frozen' flag to determine when to free or allocate the policy
structure vs when to restore the policy from the saved fallback storage.
Thus we can successfully preserve the structure across suspend/resume.
Effectively, this helps us complete the separation of the 'light-weight'
and the 'full' init/tear-down sequences in the cpufreq subsystem, so that
this can be made use of in the suspend/resume scenario.
Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2013-07-30 06:55:10 +08:00
|
|
|
if (frozen)
|
|
|
|
/* Restore the saved policy when doing light-weight init */
|
|
|
|
policy = cpufreq_policy_restore(cpu);
|
|
|
|
else
|
|
|
|
policy = cpufreq_policy_alloc();
|
|
|
|
|
2009-07-09 04:30:03 +08:00
|
|
|
if (!policy)
|
2005-04-17 06:20:36 +08:00
|
|
|
goto nomem_out;
|
2009-07-09 04:30:03 +08:00
|
|
|
|
2005-04-17 06:20:36 +08:00
|
|
|
policy->cpu = cpu;
|
2013-02-07 13:26:03 +08:00
|
|
|
policy->governor = CPUFREQ_DEFAULT_GOVERNOR;
|
2009-01-04 21:18:06 +08:00
|
|
|
cpumask_copy(policy->cpus, cpumask_of(cpu));
|
2005-04-17 06:20:36 +08:00
|
|
|
|
2007-02-06 08:12:44 +08:00
|
|
|
/* Initially set CPU itself as the policy_cpu */
|
2009-10-29 21:34:13 +08:00
|
|
|
per_cpu(cpufreq_policy_cpu, cpu) = cpu;
|
2007-02-06 08:12:44 +08:00
|
|
|
|
2005-04-17 06:20:36 +08:00
|
|
|
init_completion(&policy->kobj_unregister);
|
2006-11-22 22:55:48 +08:00
|
|
|
INIT_WORK(&policy->update, handle_update);
|
2005-04-17 06:20:36 +08:00
|
|
|
|
|
|
|
/* call driver. From then on the cpufreq must be able
|
|
|
|
* to accept all calls to ->verify and ->setpolicy for this CPU
|
|
|
|
*/
|
2013-04-29 06:08:16 +08:00
|
|
|
ret = cpufreq_driver->init(policy);
|
2005-04-17 06:20:36 +08:00
|
|
|
if (ret) {
|
2011-03-27 21:04:46 +08:00
|
|
|
pr_debug("initialization failed\n");
|
2013-02-07 13:25:00 +08:00
|
|
|
goto err_set_policy_cpu;
|
2005-04-17 06:20:36 +08:00
|
|
|
}
|
2013-01-12 13:14:38 +08:00
|
|
|
|
2013-01-29 22:39:08 +08:00
|
|
|
/* related cpus should atleast have policy->cpus */
|
|
|
|
cpumask_or(policy->related_cpus, policy->related_cpus, policy->cpus);
|
|
|
|
|
2013-01-12 13:14:38 +08:00
|
|
|
/*
|
|
|
|
* affected cpus must always be the one, which are online. We aren't
|
|
|
|
* managing offline cpus here.
|
|
|
|
*/
|
|
|
|
cpumask_and(policy->cpus, policy->cpus, cpu_online_mask);
|
|
|
|
|
2008-12-05 04:19:17 +08:00
|
|
|
policy->user_policy.min = policy->min;
|
|
|
|
policy->user_policy.max = policy->max;
|
2005-04-17 06:20:36 +08:00
|
|
|
|
2008-07-30 13:32:58 +08:00
|
|
|
blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
|
|
|
|
CPUFREQ_START, policy);
|
|
|
|
|
2013-01-29 22:39:08 +08:00
|
|
|
#ifdef CONFIG_HOTPLUG_CPU
|
|
|
|
gov = __find_governor(per_cpu(cpufreq_cpu_governor, cpu));
|
|
|
|
if (gov) {
|
|
|
|
policy->governor = gov;
|
|
|
|
pr_debug("Restoring governor %s for cpu %d\n",
|
|
|
|
policy->governor->name, cpu);
|
2009-07-24 21:25:03 +08:00
|
|
|
}
|
2013-01-29 22:39:08 +08:00
|
|
|
#endif
|
2005-04-17 06:20:36 +08:00
|
|
|
|
2013-07-30 06:54:23 +08:00
|
|
|
write_lock_irqsave(&cpufreq_driver_lock, flags);
|
|
|
|
for_each_cpu(j, policy->cpus) {
|
|
|
|
per_cpu(cpufreq_cpu_data, j) = policy;
|
|
|
|
per_cpu(cpufreq_policy_cpu, j) = policy->cpu;
|
|
|
|
}
|
|
|
|
write_unlock_irqrestore(&cpufreq_driver_lock, flags);
|
|
|
|
|
2013-07-30 06:54:49 +08:00
|
|
|
if (!frozen) {
|
2013-07-31 20:35:14 +08:00
|
|
|
ret = cpufreq_add_dev_interface(policy, dev);
|
2013-07-30 06:54:49 +08:00
|
|
|
if (ret)
|
|
|
|
goto err_out_unregister;
|
2013-08-07 01:23:08 +08:00
|
|
|
|
|
|
|
write_lock_irqsave(&cpufreq_driver_lock, flags);
|
|
|
|
list_add(&policy->policy_list, &cpufreq_policy_list);
|
|
|
|
write_unlock_irqrestore(&cpufreq_driver_lock, flags);
|
2013-07-30 06:54:49 +08:00
|
|
|
}
|
2006-03-05 16:37:23 +08:00
|
|
|
|
2013-07-30 06:54:23 +08:00
|
|
|
cpufreq_init_policy(policy);
|
|
|
|
|
2007-12-18 03:54:39 +08:00
|
|
|
kobject_uevent(&policy->kobj, KOBJ_ADD);
|
2013-04-29 06:08:16 +08:00
|
|
|
module_put(cpufreq_driver->owner);
|
2011-03-27 21:04:46 +08:00
|
|
|
pr_debug("initialization complete\n");
|
2006-03-29 14:48:37 +08:00
|
|
|
|
2005-04-17 06:20:36 +08:00
|
|
|
return 0;
|
|
|
|
|
|
|
|
err_out_unregister:
|
2013-02-23 00:24:34 +08:00
|
|
|
write_lock_irqsave(&cpufreq_driver_lock, flags);
|
2013-07-30 06:54:23 +08:00
|
|
|
for_each_cpu(j, policy->cpus) {
|
2008-03-26 06:06:53 +08:00
|
|
|
per_cpu(cpufreq_cpu_data, j) = NULL;
|
2013-07-30 06:54:23 +08:00
|
|
|
if (j != cpu)
|
|
|
|
per_cpu(cpufreq_policy_cpu, j) = -1;
|
|
|
|
}
|
2013-02-23 00:24:34 +08:00
|
|
|
write_unlock_irqrestore(&cpufreq_driver_lock, flags);
|
2005-04-17 06:20:36 +08:00
|
|
|
|
2013-02-07 13:25:00 +08:00
|
|
|
err_set_policy_cpu:
|
|
|
|
per_cpu(cpufreq_policy_cpu, cpu) = -1;
|
2013-07-30 06:54:11 +08:00
|
|
|
cpufreq_policy_free(policy);
|
2005-04-17 06:20:36 +08:00
|
|
|
nomem_out:
|
2013-04-29 06:08:16 +08:00
|
|
|
module_put(cpufreq_driver->owner);
|
2005-10-31 06:59:54 +08:00
|
|
|
module_out:
|
2005-04-17 06:20:36 +08:00
|
|
|
return ret;
|
|
|
|
}
|
|
|
|
|
2013-07-30 06:54:49 +08:00
|
|
|
/**
|
|
|
|
* cpufreq_add_dev - add a CPU device
|
|
|
|
*
|
|
|
|
* Adds the cpufreq interface for a CPU device.
|
|
|
|
*
|
|
|
|
* The Oracle says: try running cpufreq registration/unregistration concurrently
|
|
|
|
* with with cpu hotplugging and all hell will break loose. Tried to clean this
|
|
|
|
* mess up, but more thorough testing is needed. - Mathieu
|
|
|
|
*/
|
|
|
|
static int cpufreq_add_dev(struct device *dev, struct subsys_interface *sif)
|
|
|
|
{
|
|
|
|
return __cpufreq_add_dev(dev, sif, false);
|
|
|
|
}
|
|
|
|
|
2013-01-14 21:23:03 +08:00
|
|
|
static void update_policy_cpu(struct cpufreq_policy *policy, unsigned int cpu)
|
|
|
|
{
|
|
|
|
int j;
|
|
|
|
|
|
|
|
policy->last_cpu = policy->cpu;
|
|
|
|
policy->cpu = cpu;
|
|
|
|
|
2013-02-04 19:38:51 +08:00
|
|
|
for_each_cpu(j, policy->cpus)
|
2013-01-14 21:23:03 +08:00
|
|
|
per_cpu(cpufreq_policy_cpu, j) = cpu;
|
|
|
|
|
|
|
|
#ifdef CONFIG_CPU_FREQ_TABLE
|
|
|
|
cpufreq_frequency_table_update_policy_cpu(policy);
|
|
|
|
#endif
|
|
|
|
blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
|
|
|
|
CPUFREQ_UPDATE_POLICY_CPU, policy);
|
|
|
|
}
|
2005-04-17 06:20:36 +08:00
|
|
|
|
2013-08-07 01:23:05 +08:00
|
|
|
static int cpufreq_nominate_new_policy_cpu(struct cpufreq_policy *policy,
|
2013-07-30 06:54:49 +08:00
|
|
|
unsigned int old_cpu, bool frozen)
|
2013-07-30 06:54:36 +08:00
|
|
|
{
|
|
|
|
struct device *cpu_dev;
|
|
|
|
unsigned long flags;
|
|
|
|
int ret;
|
|
|
|
|
|
|
|
/* first sibling now owns the new sysfs dir */
|
2013-08-07 01:23:05 +08:00
|
|
|
cpu_dev = get_cpu_device(cpumask_first(policy->cpus));
|
2013-07-30 06:54:49 +08:00
|
|
|
|
|
|
|
/* Don't touch sysfs files during light-weight tear-down */
|
|
|
|
if (frozen)
|
|
|
|
return cpu_dev->id;
|
|
|
|
|
2013-07-30 06:54:36 +08:00
|
|
|
sysfs_remove_link(&cpu_dev->kobj, "cpufreq");
|
2013-08-07 01:23:05 +08:00
|
|
|
ret = kobject_move(&policy->kobj, &cpu_dev->kobj);
|
2013-07-30 06:54:36 +08:00
|
|
|
if (ret) {
|
|
|
|
pr_err("%s: Failed to move kobj: %d", __func__, ret);
|
|
|
|
|
|
|
|
WARN_ON(lock_policy_rwsem_write(old_cpu));
|
2013-08-07 01:23:05 +08:00
|
|
|
cpumask_set_cpu(old_cpu, policy->cpus);
|
2013-07-30 06:54:36 +08:00
|
|
|
|
|
|
|
write_lock_irqsave(&cpufreq_driver_lock, flags);
|
2013-08-07 01:23:05 +08:00
|
|
|
per_cpu(cpufreq_cpu_data, old_cpu) = policy;
|
2013-07-30 06:54:36 +08:00
|
|
|
write_unlock_irqrestore(&cpufreq_driver_lock, flags);
|
|
|
|
|
|
|
|
unlock_policy_rwsem_write(old_cpu);
|
|
|
|
|
2013-08-07 01:23:05 +08:00
|
|
|
ret = sysfs_create_link(&cpu_dev->kobj, &policy->kobj,
|
2013-07-30 06:54:36 +08:00
|
|
|
"cpufreq");
|
|
|
|
|
|
|
|
return -EINVAL;
|
|
|
|
}
|
|
|
|
|
|
|
|
return cpu_dev->id;
|
|
|
|
}
|
|
|
|
|
2005-04-17 06:20:36 +08:00
|
|
|
/**
|
2007-02-06 08:12:44 +08:00
|
|
|
* __cpufreq_remove_dev - remove a CPU device
|
2005-04-17 06:20:36 +08:00
|
|
|
*
|
|
|
|
* Removes the cpufreq interface for a CPU device.
|
2007-02-06 08:12:44 +08:00
|
|
|
* Caller should already have policy_rwsem in write mode for this CPU.
|
|
|
|
* This routine frees the rwsem before returning.
|
2005-04-17 06:20:36 +08:00
|
|
|
*/
|
2013-06-19 16:49:33 +08:00
|
|
|
static int __cpufreq_remove_dev(struct device *dev,
|
2013-07-30 06:54:49 +08:00
|
|
|
struct subsys_interface *sif, bool frozen)
|
2005-04-17 06:20:36 +08:00
|
|
|
{
|
2013-07-30 06:54:36 +08:00
|
|
|
unsigned int cpu = dev->id, cpus;
|
|
|
|
int new_cpu;
|
2005-04-17 06:20:36 +08:00
|
|
|
unsigned long flags;
|
2013-08-07 01:23:05 +08:00
|
|
|
struct cpufreq_policy *policy;
|
2010-03-04 16:23:46 +08:00
|
|
|
struct kobject *kobj;
|
|
|
|
struct completion *cmp;
|
2005-04-17 06:20:36 +08:00
|
|
|
|
2013-01-14 21:23:03 +08:00
|
|
|
pr_debug("%s: unregistering CPU %u\n", __func__, cpu);
|
2005-04-17 06:20:36 +08:00
|
|
|
|
2013-02-23 00:24:34 +08:00
|
|
|
write_lock_irqsave(&cpufreq_driver_lock, flags);
|
2013-02-07 13:25:00 +08:00
|
|
|
|
2013-08-07 01:23:05 +08:00
|
|
|
policy = per_cpu(cpufreq_cpu_data, cpu);
|
2013-02-07 13:25:00 +08:00
|
|
|
per_cpu(cpufreq_cpu_data, cpu) = NULL;
|
|
|
|
|
cpufreq: Preserve policy structure across suspend/resume
To perform light-weight cpu-init and teardown in the cpufreq subsystem
during suspend/resume, we need to separate out the 2 main functionalities
of the cpufreq CPU hotplug callbacks, as outlined below:
1. Init/tear-down of core cpufreq and CPU-specific components, which are
critical to the correct functioning of the cpufreq subsystem.
2. Init/tear-down of cpufreq sysfs files during suspend/resume.
The first part requires accurate updates to the policy structure such as
its ->cpus and ->related_cpus masks, whereas the second part requires that
the policy->kobj structure is not released or re-initialized during
suspend/resume.
To handle both these requirements, we need to allow updates to the policy
structure throughout suspend/resume, but prevent the structure from getting
freed up. Also, we must have a mechanism by which the cpu-up callbacks can
restore the policy structure, without allocating things afresh. (That also
helps avoid memory leaks).
To achieve this, we use 2 schemes:
a. Use a fallback per-cpu storage area for preserving the policy structures
during suspend, so that they can be restored during resume appropriately.
b. Use the 'frozen' flag to determine when to free or allocate the policy
structure vs when to restore the policy from the saved fallback storage.
Thus we can successfully preserve the structure across suspend/resume.
Effectively, this helps us complete the separation of the 'light-weight'
and the 'full' init/tear-down sequences in the cpufreq subsystem, so that
this can be made use of in the suspend/resume scenario.
Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2013-07-30 06:55:10 +08:00
|
|
|
/* Save the policy somewhere when doing a light-weight tear-down */
|
|
|
|
if (frozen)
|
2013-08-07 01:23:05 +08:00
|
|
|
per_cpu(cpufreq_cpu_data_fallback, cpu) = policy;
|
cpufreq: Preserve policy structure across suspend/resume
To perform light-weight cpu-init and teardown in the cpufreq subsystem
during suspend/resume, we need to separate out the 2 main functionalities
of the cpufreq CPU hotplug callbacks, as outlined below:
1. Init/tear-down of core cpufreq and CPU-specific components, which are
critical to the correct functioning of the cpufreq subsystem.
2. Init/tear-down of cpufreq sysfs files during suspend/resume.
The first part requires accurate updates to the policy structure such as
its ->cpus and ->related_cpus masks, whereas the second part requires that
the policy->kobj structure is not released or re-initialized during
suspend/resume.
To handle both these requirements, we need to allow updates to the policy
structure throughout suspend/resume, but prevent the structure from getting
freed up. Also, we must have a mechanism by which the cpu-up callbacks can
restore the policy structure, without allocating things afresh. (That also
helps avoid memory leaks).
To achieve this, we use 2 schemes:
a. Use a fallback per-cpu storage area for preserving the policy structures
during suspend, so that they can be restored during resume appropriately.
b. Use the 'frozen' flag to determine when to free or allocate the policy
structure vs when to restore the policy from the saved fallback storage.
Thus we can successfully preserve the structure across suspend/resume.
Effectively, this helps us complete the separation of the 'light-weight'
and the 'full' init/tear-down sequences in the cpufreq subsystem, so that
this can be made use of in the suspend/resume scenario.
Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2013-07-30 06:55:10 +08:00
|
|
|
|
2013-02-23 00:24:34 +08:00
|
|
|
write_unlock_irqrestore(&cpufreq_driver_lock, flags);
|
2005-04-17 06:20:36 +08:00
|
|
|
|
2013-08-07 01:23:05 +08:00
|
|
|
if (!policy) {
|
2013-01-14 21:23:03 +08:00
|
|
|
pr_debug("%s: No cpu_data found\n", __func__);
|
2005-04-17 06:20:36 +08:00
|
|
|
return -EINVAL;
|
|
|
|
}
|
|
|
|
|
2013-04-29 06:08:16 +08:00
|
|
|
if (cpufreq_driver->target)
|
2013-08-07 01:23:05 +08:00
|
|
|
__cpufreq_governor(policy, CPUFREQ_GOV_STOP);
|
2005-04-17 06:20:36 +08:00
|
|
|
|
2007-07-10 02:35:28 +08:00
|
|
|
#ifdef CONFIG_HOTPLUG_CPU
|
2013-04-29 06:08:16 +08:00
|
|
|
if (!cpufreq_driver->setpolicy)
|
2013-02-07 01:02:11 +08:00
|
|
|
strncpy(per_cpu(cpufreq_cpu_governor, cpu),
|
2013-08-07 01:23:05 +08:00
|
|
|
policy->governor->name, CPUFREQ_NAME_LEN);
|
2005-04-17 06:20:36 +08:00
|
|
|
#endif
|
|
|
|
|
2013-02-07 13:25:00 +08:00
|
|
|
WARN_ON(lock_policy_rwsem_write(cpu));
|
2013-08-07 01:23:05 +08:00
|
|
|
cpus = cpumask_weight(policy->cpus);
|
2013-04-11 16:04:53 +08:00
|
|
|
|
|
|
|
if (cpus > 1)
|
2013-08-07 01:23:05 +08:00
|
|
|
cpumask_clear_cpu(cpu, policy->cpus);
|
2013-02-07 13:25:00 +08:00
|
|
|
unlock_policy_rwsem_write(cpu);
|
2007-07-10 02:35:28 +08:00
|
|
|
|
2013-08-07 01:23:05 +08:00
|
|
|
if (cpu != policy->cpu && !frozen) {
|
2013-02-06 05:21:14 +08:00
|
|
|
sysfs_remove_link(&dev->kobj, "cpufreq");
|
|
|
|
} else if (cpus > 1) {
|
2007-07-10 02:35:28 +08:00
|
|
|
|
2013-08-07 01:23:05 +08:00
|
|
|
new_cpu = cpufreq_nominate_new_policy_cpu(policy, cpu, frozen);
|
2013-07-30 06:54:36 +08:00
|
|
|
if (new_cpu >= 0) {
|
2013-02-07 13:25:00 +08:00
|
|
|
WARN_ON(lock_policy_rwsem_write(cpu));
|
2013-08-07 01:23:05 +08:00
|
|
|
update_policy_cpu(policy, new_cpu);
|
2010-03-04 16:23:46 +08:00
|
|
|
unlock_policy_rwsem_write(cpu);
|
2013-07-30 06:54:49 +08:00
|
|
|
|
|
|
|
if (!frozen) {
|
|
|
|
pr_debug("%s: policy Kobject moved to cpu: %d "
|
|
|
|
"from: %d\n",__func__, new_cpu, cpu);
|
|
|
|
}
|
2005-04-17 06:20:36 +08:00
|
|
|
}
|
|
|
|
}
|
|
|
|
|
2013-01-14 21:23:03 +08:00
|
|
|
/* If cpu is last user of policy, free policy */
|
|
|
|
if (cpus == 1) {
|
cpufreq: Fix cpufreq driver module refcount balance after suspend/resume
Since cpufreq_cpu_put() called by __cpufreq_remove_dev() drops the
driver module refcount, __cpufreq_remove_dev() causes that refcount
to become negative for the cpufreq driver after a suspend/resume
cycle.
This is not the only bad thing that happens there, however, because
kobject_put() should only be called for the policy kobject at this
point if the CPU is not the last one for that policy.
Namely, if the given CPU is the last one for that policy, the
policy kobject's refcount should be 1 at this point, as set by
cpufreq_add_dev_interface(), and only needs to be dropped once for
the kobject to go away. This actually happens under the cpu == 1
check, so it need not be done before by cpufreq_cpu_put().
On the other hand, if the given CPU is not the last one for that
policy, this means that cpufreq_add_policy_cpu() has been called
at least once for that policy and cpufreq_cpu_get() has been
called for it too. To balance that cpufreq_cpu_get(), we need to
call cpufreq_cpu_put() in that case.
Thus, to fix the described problem and keep the reference
counters balanced in both cases, move the cpufreq_cpu_get() call
in __cpufreq_remove_dev() to the code path executed only for
CPUs that share the policy with other CPUs.
Reported-and-tested-by: Toralf Förster <toralf.foerster@gmx.de>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Cc: 3.10+ <stable@vger.kernel.org>
2013-07-30 06:32:00 +08:00
|
|
|
if (cpufreq_driver->target)
|
2013-08-07 01:23:05 +08:00
|
|
|
__cpufreq_governor(policy, CPUFREQ_GOV_POLICY_EXIT);
|
cpufreq: Fix cpufreq driver module refcount balance after suspend/resume
Since cpufreq_cpu_put() called by __cpufreq_remove_dev() drops the
driver module refcount, __cpufreq_remove_dev() causes that refcount
to become negative for the cpufreq driver after a suspend/resume
cycle.
This is not the only bad thing that happens there, however, because
kobject_put() should only be called for the policy kobject at this
point if the CPU is not the last one for that policy.
Namely, if the given CPU is the last one for that policy, the
policy kobject's refcount should be 1 at this point, as set by
cpufreq_add_dev_interface(), and only needs to be dropped once for
the kobject to go away. This actually happens under the cpu == 1
check, so it need not be done before by cpufreq_cpu_put().
On the other hand, if the given CPU is not the last one for that
policy, this means that cpufreq_add_policy_cpu() has been called
at least once for that policy and cpufreq_cpu_get() has been
called for it too. To balance that cpufreq_cpu_get(), we need to
call cpufreq_cpu_put() in that case.
Thus, to fix the described problem and keep the reference
counters balanced in both cases, move the cpufreq_cpu_get() call
in __cpufreq_remove_dev() to the code path executed only for
CPUs that share the policy with other CPUs.
Reported-and-tested-by: Toralf Förster <toralf.foerster@gmx.de>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Cc: 3.10+ <stable@vger.kernel.org>
2013-07-30 06:32:00 +08:00
|
|
|
|
cpufreq: Preserve policy structure across suspend/resume
To perform light-weight cpu-init and teardown in the cpufreq subsystem
during suspend/resume, we need to separate out the 2 main functionalities
of the cpufreq CPU hotplug callbacks, as outlined below:
1. Init/tear-down of core cpufreq and CPU-specific components, which are
critical to the correct functioning of the cpufreq subsystem.
2. Init/tear-down of cpufreq sysfs files during suspend/resume.
The first part requires accurate updates to the policy structure such as
its ->cpus and ->related_cpus masks, whereas the second part requires that
the policy->kobj structure is not released or re-initialized during
suspend/resume.
To handle both these requirements, we need to allow updates to the policy
structure throughout suspend/resume, but prevent the structure from getting
freed up. Also, we must have a mechanism by which the cpu-up callbacks can
restore the policy structure, without allocating things afresh. (That also
helps avoid memory leaks).
To achieve this, we use 2 schemes:
a. Use a fallback per-cpu storage area for preserving the policy structures
during suspend, so that they can be restored during resume appropriately.
b. Use the 'frozen' flag to determine when to free or allocate the policy
structure vs when to restore the policy from the saved fallback storage.
Thus we can successfully preserve the structure across suspend/resume.
Effectively, this helps us complete the separation of the 'light-weight'
and the 'full' init/tear-down sequences in the cpufreq subsystem, so that
this can be made use of in the suspend/resume scenario.
Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2013-07-30 06:55:10 +08:00
|
|
|
if (!frozen) {
|
|
|
|
lock_policy_rwsem_read(cpu);
|
2013-08-07 01:23:05 +08:00
|
|
|
kobj = &policy->kobj;
|
|
|
|
cmp = &policy->kobj_unregister;
|
cpufreq: Preserve policy structure across suspend/resume
To perform light-weight cpu-init and teardown in the cpufreq subsystem
during suspend/resume, we need to separate out the 2 main functionalities
of the cpufreq CPU hotplug callbacks, as outlined below:
1. Init/tear-down of core cpufreq and CPU-specific components, which are
critical to the correct functioning of the cpufreq subsystem.
2. Init/tear-down of cpufreq sysfs files during suspend/resume.
The first part requires accurate updates to the policy structure such as
its ->cpus and ->related_cpus masks, whereas the second part requires that
the policy->kobj structure is not released or re-initialized during
suspend/resume.
To handle both these requirements, we need to allow updates to the policy
structure throughout suspend/resume, but prevent the structure from getting
freed up. Also, we must have a mechanism by which the cpu-up callbacks can
restore the policy structure, without allocating things afresh. (That also
helps avoid memory leaks).
To achieve this, we use 2 schemes:
a. Use a fallback per-cpu storage area for preserving the policy structures
during suspend, so that they can be restored during resume appropriately.
b. Use the 'frozen' flag to determine when to free or allocate the policy
structure vs when to restore the policy from the saved fallback storage.
Thus we can successfully preserve the structure across suspend/resume.
Effectively, this helps us complete the separation of the 'light-weight'
and the 'full' init/tear-down sequences in the cpufreq subsystem, so that
this can be made use of in the suspend/resume scenario.
Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2013-07-30 06:55:10 +08:00
|
|
|
unlock_policy_rwsem_read(cpu);
|
|
|
|
kobject_put(kobj);
|
|
|
|
|
|
|
|
/*
|
|
|
|
* We need to make sure that the underlying kobj is
|
|
|
|
* actually not referenced anymore by anybody before we
|
|
|
|
* proceed with unloading.
|
|
|
|
*/
|
|
|
|
pr_debug("waiting for dropping of refcount\n");
|
|
|
|
wait_for_completion(cmp);
|
|
|
|
pr_debug("wait complete\n");
|
|
|
|
}
|
2009-07-03 08:08:30 +08:00
|
|
|
|
cpufreq: Preserve policy structure across suspend/resume
To perform light-weight cpu-init and teardown in the cpufreq subsystem
during suspend/resume, we need to separate out the 2 main functionalities
of the cpufreq CPU hotplug callbacks, as outlined below:
1. Init/tear-down of core cpufreq and CPU-specific components, which are
critical to the correct functioning of the cpufreq subsystem.
2. Init/tear-down of cpufreq sysfs files during suspend/resume.
The first part requires accurate updates to the policy structure such as
its ->cpus and ->related_cpus masks, whereas the second part requires that
the policy->kobj structure is not released or re-initialized during
suspend/resume.
To handle both these requirements, we need to allow updates to the policy
structure throughout suspend/resume, but prevent the structure from getting
freed up. Also, we must have a mechanism by which the cpu-up callbacks can
restore the policy structure, without allocating things afresh. (That also
helps avoid memory leaks).
To achieve this, we use 2 schemes:
a. Use a fallback per-cpu storage area for preserving the policy structures
during suspend, so that they can be restored during resume appropriately.
b. Use the 'frozen' flag to determine when to free or allocate the policy
structure vs when to restore the policy from the saved fallback storage.
Thus we can successfully preserve the structure across suspend/resume.
Effectively, this helps us complete the separation of the 'light-weight'
and the 'full' init/tear-down sequences in the cpufreq subsystem, so that
this can be made use of in the suspend/resume scenario.
Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2013-07-30 06:55:10 +08:00
|
|
|
/*
|
|
|
|
* Perform the ->exit() even during light-weight tear-down,
|
|
|
|
* since this is a core component, and is essential for the
|
|
|
|
* subsequent light-weight ->init() to succeed.
|
2013-01-14 21:23:03 +08:00
|
|
|
*/
|
2013-04-29 06:08:16 +08:00
|
|
|
if (cpufreq_driver->exit)
|
2013-08-07 01:23:05 +08:00
|
|
|
cpufreq_driver->exit(policy);
|
[CPUFREQ] CPU hotplug, re-create sysfs directory and symlinks
When we discover CPUs that are affected by each other's
frequency/voltage transitions, the first CPU gets a sysfs directory
created, and rest of the siblings get symlinks. Currently, when we
hotplug off only the first CPU, all of the symlinks and the sysfs
directory gets removed. Even though rest of the siblings are still
online and functional, they are orphaned, and no longer governed by
cpufreq.
This patch, given the above scenario, creates a sysfs directory for
the first sibling and symlinks for the rest of the siblings.
Please note the recursive call, it was rather too ugly to roll it
out. And the removal of redundant NULL setting (it is already taken
care of near the top of the function).
Signed-off-by: Jacob Shin <jacob.shin@amd.com>
Acked-by: Mark Langsdorf <mark.langsdorf@amd.com>
Reviewed-by: Thomas Renninger <trenn@suse.de>
Signed-off-by: Dave Jones <davej@redhat.com>
Cc: stable@kernel.org
2011-04-28 02:32:11 +08:00
|
|
|
|
cpufreq: Preserve policy structure across suspend/resume
To perform light-weight cpu-init and teardown in the cpufreq subsystem
during suspend/resume, we need to separate out the 2 main functionalities
of the cpufreq CPU hotplug callbacks, as outlined below:
1. Init/tear-down of core cpufreq and CPU-specific components, which are
critical to the correct functioning of the cpufreq subsystem.
2. Init/tear-down of cpufreq sysfs files during suspend/resume.
The first part requires accurate updates to the policy structure such as
its ->cpus and ->related_cpus masks, whereas the second part requires that
the policy->kobj structure is not released or re-initialized during
suspend/resume.
To handle both these requirements, we need to allow updates to the policy
structure throughout suspend/resume, but prevent the structure from getting
freed up. Also, we must have a mechanism by which the cpu-up callbacks can
restore the policy structure, without allocating things afresh. (That also
helps avoid memory leaks).
To achieve this, we use 2 schemes:
a. Use a fallback per-cpu storage area for preserving the policy structures
during suspend, so that they can be restored during resume appropriately.
b. Use the 'frozen' flag to determine when to free or allocate the policy
structure vs when to restore the policy from the saved fallback storage.
Thus we can successfully preserve the structure across suspend/resume.
Effectively, this helps us complete the separation of the 'light-weight'
and the 'full' init/tear-down sequences in the cpufreq subsystem, so that
this can be made use of in the suspend/resume scenario.
Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2013-07-30 06:55:10 +08:00
|
|
|
if (!frozen)
|
2013-08-07 01:23:05 +08:00
|
|
|
cpufreq_policy_free(policy);
|
cpufreq: Fix cpufreq driver module refcount balance after suspend/resume
Since cpufreq_cpu_put() called by __cpufreq_remove_dev() drops the
driver module refcount, __cpufreq_remove_dev() causes that refcount
to become negative for the cpufreq driver after a suspend/resume
cycle.
This is not the only bad thing that happens there, however, because
kobject_put() should only be called for the policy kobject at this
point if the CPU is not the last one for that policy.
Namely, if the given CPU is the last one for that policy, the
policy kobject's refcount should be 1 at this point, as set by
cpufreq_add_dev_interface(), and only needs to be dropped once for
the kobject to go away. This actually happens under the cpu == 1
check, so it need not be done before by cpufreq_cpu_put().
On the other hand, if the given CPU is not the last one for that
policy, this means that cpufreq_add_policy_cpu() has been called
at least once for that policy and cpufreq_cpu_get() has been
called for it too. To balance that cpufreq_cpu_get(), we need to
call cpufreq_cpu_put() in that case.
Thus, to fix the described problem and keep the reference
counters balanced in both cases, move the cpufreq_cpu_get() call
in __cpufreq_remove_dev() to the code path executed only for
CPUs that share the policy with other CPUs.
Reported-and-tested-by: Toralf Förster <toralf.foerster@gmx.de>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Cc: 3.10+ <stable@vger.kernel.org>
2013-07-30 06:32:00 +08:00
|
|
|
} else {
|
|
|
|
if (cpufreq_driver->target) {
|
2013-08-07 01:23:05 +08:00
|
|
|
__cpufreq_governor(policy, CPUFREQ_GOV_START);
|
|
|
|
__cpufreq_governor(policy, CPUFREQ_GOV_LIMITS);
|
cpufreq: Fix cpufreq driver module refcount balance after suspend/resume
Since cpufreq_cpu_put() called by __cpufreq_remove_dev() drops the
driver module refcount, __cpufreq_remove_dev() causes that refcount
to become negative for the cpufreq driver after a suspend/resume
cycle.
This is not the only bad thing that happens there, however, because
kobject_put() should only be called for the policy kobject at this
point if the CPU is not the last one for that policy.
Namely, if the given CPU is the last one for that policy, the
policy kobject's refcount should be 1 at this point, as set by
cpufreq_add_dev_interface(), and only needs to be dropped once for
the kobject to go away. This actually happens under the cpu == 1
check, so it need not be done before by cpufreq_cpu_put().
On the other hand, if the given CPU is not the last one for that
policy, this means that cpufreq_add_policy_cpu() has been called
at least once for that policy and cpufreq_cpu_get() has been
called for it too. To balance that cpufreq_cpu_get(), we need to
call cpufreq_cpu_put() in that case.
Thus, to fix the described problem and keep the reference
counters balanced in both cases, move the cpufreq_cpu_get() call
in __cpufreq_remove_dev() to the code path executed only for
CPUs that share the policy with other CPUs.
Reported-and-tested-by: Toralf Förster <toralf.foerster@gmx.de>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Cc: 3.10+ <stable@vger.kernel.org>
2013-07-30 06:32:00 +08:00
|
|
|
}
|
[CPUFREQ] CPU hotplug, re-create sysfs directory and symlinks
When we discover CPUs that are affected by each other's
frequency/voltage transitions, the first CPU gets a sysfs directory
created, and rest of the siblings get symlinks. Currently, when we
hotplug off only the first CPU, all of the symlinks and the sysfs
directory gets removed. Even though rest of the siblings are still
online and functional, they are orphaned, and no longer governed by
cpufreq.
This patch, given the above scenario, creates a sysfs directory for
the first sibling and symlinks for the rest of the siblings.
Please note the recursive call, it was rather too ugly to roll it
out. And the removal of redundant NULL setting (it is already taken
care of near the top of the function).
Signed-off-by: Jacob Shin <jacob.shin@amd.com>
Acked-by: Mark Langsdorf <mark.langsdorf@amd.com>
Reviewed-by: Thomas Renninger <trenn@suse.de>
Signed-off-by: Dave Jones <davej@redhat.com>
Cc: stable@kernel.org
2011-04-28 02:32:11 +08:00
|
|
|
}
|
2005-04-17 06:20:36 +08:00
|
|
|
|
2013-02-07 13:25:00 +08:00
|
|
|
per_cpu(cpufreq_policy_cpu, cpu) = -1;
|
2005-04-17 06:20:36 +08:00
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
2011-12-22 06:29:42 +08:00
|
|
|
static int cpufreq_remove_dev(struct device *dev, struct subsys_interface *sif)
|
2007-02-06 08:12:44 +08:00
|
|
|
{
|
2011-12-22 06:29:42 +08:00
|
|
|
unsigned int cpu = dev->id;
|
2007-02-06 08:12:44 +08:00
|
|
|
int retval;
|
2007-03-27 03:03:19 +08:00
|
|
|
|
|
|
|
if (cpu_is_offline(cpu))
|
|
|
|
return 0;
|
|
|
|
|
2013-07-30 06:54:49 +08:00
|
|
|
retval = __cpufreq_remove_dev(dev, sif, false);
|
2007-02-06 08:12:44 +08:00
|
|
|
return retval;
|
|
|
|
}
|
|
|
|
|
2006-11-22 22:55:48 +08:00
|
|
|
static void handle_update(struct work_struct *work)
|
2005-04-17 06:20:36 +08:00
|
|
|
{
|
2006-11-22 22:55:48 +08:00
|
|
|
struct cpufreq_policy *policy =
|
|
|
|
container_of(work, struct cpufreq_policy, update);
|
|
|
|
unsigned int cpu = policy->cpu;
|
2011-03-27 21:04:46 +08:00
|
|
|
pr_debug("handle_update for cpu %u called\n", cpu);
|
2005-04-17 06:20:36 +08:00
|
|
|
cpufreq_update_policy(cpu);
|
|
|
|
}
|
|
|
|
|
|
|
|
/**
|
2013-06-19 16:49:33 +08:00
|
|
|
* cpufreq_out_of_sync - If actual and saved CPU frequency differs, we're
|
|
|
|
* in deep trouble.
|
2005-04-17 06:20:36 +08:00
|
|
|
* @cpu: cpu number
|
|
|
|
* @old_freq: CPU frequency the kernel thinks the CPU runs at
|
|
|
|
* @new_freq: CPU frequency the CPU actually runs at
|
|
|
|
*
|
2009-01-18 14:37:11 +08:00
|
|
|
* We adjust to current frequency first, and need to clean up later.
|
|
|
|
* So either call to cpufreq_update_policy() or schedule handle_update()).
|
2005-04-17 06:20:36 +08:00
|
|
|
*/
|
2006-10-26 18:50:58 +08:00
|
|
|
static void cpufreq_out_of_sync(unsigned int cpu, unsigned int old_freq,
|
|
|
|
unsigned int new_freq)
|
2005-04-17 06:20:36 +08:00
|
|
|
{
|
2013-03-24 14:26:43 +08:00
|
|
|
struct cpufreq_policy *policy;
|
2005-04-17 06:20:36 +08:00
|
|
|
struct cpufreq_freqs freqs;
|
2013-03-24 14:26:43 +08:00
|
|
|
unsigned long flags;
|
|
|
|
|
2011-03-27 21:04:46 +08:00
|
|
|
pr_debug("Warning: CPU frequency out of sync: cpufreq and timing "
|
2005-04-17 06:20:36 +08:00
|
|
|
"core thinks of %u, is %u kHz.\n", old_freq, new_freq);
|
|
|
|
|
|
|
|
freqs.old = old_freq;
|
|
|
|
freqs.new = new_freq;
|
2013-03-24 14:26:43 +08:00
|
|
|
|
|
|
|
read_lock_irqsave(&cpufreq_driver_lock, flags);
|
|
|
|
policy = per_cpu(cpufreq_cpu_data, cpu);
|
|
|
|
read_unlock_irqrestore(&cpufreq_driver_lock, flags);
|
|
|
|
|
|
|
|
cpufreq_notify_transition(policy, &freqs, CPUFREQ_PRECHANGE);
|
|
|
|
cpufreq_notify_transition(policy, &freqs, CPUFREQ_POSTCHANGE);
|
2005-04-17 06:20:36 +08:00
|
|
|
}
|
|
|
|
|
2006-02-28 13:43:23 +08:00
|
|
|
/**
|
2006-12-13 17:19:15 +08:00
|
|
|
* cpufreq_quick_get - get the CPU frequency (in kHz) from policy->cur
|
2005-12-03 02:43:20 +08:00
|
|
|
* @cpu: CPU number
|
|
|
|
*
|
|
|
|
* This is the last known freq, without actually getting it from the driver.
|
|
|
|
* Return value will be same as what is shown in scaling_cur_freq in sysfs.
|
|
|
|
*/
|
|
|
|
unsigned int cpufreq_quick_get(unsigned int cpu)
|
|
|
|
{
|
2013-02-07 01:02:08 +08:00
|
|
|
struct cpufreq_policy *policy;
|
2006-10-26 18:50:58 +08:00
|
|
|
unsigned int ret_freq = 0;
|
2005-12-03 02:43:20 +08:00
|
|
|
|
2013-04-29 06:08:16 +08:00
|
|
|
if (cpufreq_driver && cpufreq_driver->setpolicy && cpufreq_driver->get)
|
|
|
|
return cpufreq_driver->get(cpu);
|
2013-02-07 01:02:08 +08:00
|
|
|
|
|
|
|
policy = cpufreq_cpu_get(cpu);
|
2005-12-03 02:43:20 +08:00
|
|
|
if (policy) {
|
2006-10-26 18:50:58 +08:00
|
|
|
ret_freq = policy->cur;
|
2005-12-03 02:43:20 +08:00
|
|
|
cpufreq_cpu_put(policy);
|
|
|
|
}
|
|
|
|
|
2008-02-08 05:33:49 +08:00
|
|
|
return ret_freq;
|
2005-12-03 02:43:20 +08:00
|
|
|
}
|
|
|
|
EXPORT_SYMBOL(cpufreq_quick_get);
|
|
|
|
|
2011-06-29 01:59:12 +08:00
|
|
|
/**
|
|
|
|
* cpufreq_quick_get_max - get the max reported CPU frequency for this CPU
|
|
|
|
* @cpu: CPU number
|
|
|
|
*
|
|
|
|
* Just return the max possible frequency for a given CPU.
|
|
|
|
*/
|
|
|
|
unsigned int cpufreq_quick_get_max(unsigned int cpu)
|
|
|
|
{
|
|
|
|
struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
|
|
|
|
unsigned int ret_freq = 0;
|
|
|
|
|
|
|
|
if (policy) {
|
|
|
|
ret_freq = policy->max;
|
|
|
|
cpufreq_cpu_put(policy);
|
|
|
|
}
|
|
|
|
|
|
|
|
return ret_freq;
|
|
|
|
}
|
|
|
|
EXPORT_SYMBOL(cpufreq_quick_get_max);
|
|
|
|
|
2007-02-06 08:12:44 +08:00
|
|
|
static unsigned int __cpufreq_get(unsigned int cpu)
|
2005-04-17 06:20:36 +08:00
|
|
|
{
|
2008-03-26 06:06:53 +08:00
|
|
|
struct cpufreq_policy *policy = per_cpu(cpufreq_cpu_data, cpu);
|
2006-10-26 18:50:58 +08:00
|
|
|
unsigned int ret_freq = 0;
|
2013-04-04 22:53:25 +08:00
|
|
|
|
2013-04-29 06:08:16 +08:00
|
|
|
if (!cpufreq_driver->get)
|
2008-02-08 05:33:49 +08:00
|
|
|
return ret_freq;
|
2005-04-17 06:20:36 +08:00
|
|
|
|
2013-04-29 06:08:16 +08:00
|
|
|
ret_freq = cpufreq_driver->get(cpu);
|
2005-04-17 06:20:36 +08:00
|
|
|
|
2006-10-26 18:50:58 +08:00
|
|
|
if (ret_freq && policy->cur &&
|
2013-04-29 06:08:16 +08:00
|
|
|
!(cpufreq_driver->flags & CPUFREQ_CONST_LOOPS)) {
|
2006-10-26 18:50:58 +08:00
|
|
|
/* verify no discrepancy between actual and
|
|
|
|
saved value exists */
|
|
|
|
if (unlikely(ret_freq != policy->cur)) {
|
|
|
|
cpufreq_out_of_sync(cpu, policy->cur, ret_freq);
|
2005-04-17 06:20:36 +08:00
|
|
|
schedule_work(&policy->update);
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
2008-02-08 05:33:49 +08:00
|
|
|
return ret_freq;
|
2007-02-06 08:12:44 +08:00
|
|
|
}
|
2005-04-17 06:20:36 +08:00
|
|
|
|
2007-02-06 08:12:44 +08:00
|
|
|
/**
|
|
|
|
* cpufreq_get - get the current CPU frequency (in kHz)
|
|
|
|
* @cpu: CPU number
|
|
|
|
*
|
|
|
|
* Get the CPU current (static) CPU frequency
|
|
|
|
*/
|
|
|
|
unsigned int cpufreq_get(unsigned int cpu)
|
|
|
|
{
|
|
|
|
unsigned int ret_freq = 0;
|
|
|
|
struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
|
|
|
|
|
|
|
|
if (!policy)
|
|
|
|
goto out;
|
|
|
|
|
|
|
|
if (unlikely(lock_policy_rwsem_read(cpu)))
|
|
|
|
goto out_policy;
|
|
|
|
|
|
|
|
ret_freq = __cpufreq_get(cpu);
|
|
|
|
|
|
|
|
unlock_policy_rwsem_read(cpu);
|
2005-04-17 06:20:36 +08:00
|
|
|
|
2007-02-06 08:12:44 +08:00
|
|
|
out_policy:
|
|
|
|
cpufreq_cpu_put(policy);
|
|
|
|
out:
|
2008-02-08 05:33:49 +08:00
|
|
|
return ret_freq;
|
2005-04-17 06:20:36 +08:00
|
|
|
}
|
|
|
|
EXPORT_SYMBOL(cpufreq_get);
|
|
|
|
|
2011-12-22 06:29:42 +08:00
|
|
|
static struct subsys_interface cpufreq_interface = {
|
|
|
|
.name = "cpufreq",
|
|
|
|
.subsys = &cpu_subsys,
|
|
|
|
.add_dev = cpufreq_add_dev,
|
|
|
|
.remove_dev = cpufreq_remove_dev,
|
cpufreq: Use syscore_ops for boot CPU suspend/resume (v2)
The cpufreq subsystem uses sysdev suspend and resume for
executing cpufreq_suspend() and cpufreq_resume(), respectively,
during system suspend, after interrupts have been switched off on the
boot CPU, and during system resume, while interrupts are still off on
the boot CPU. In both cases the other CPUs are off-line at the
relevant point (either they have been switched off via CPU hotplug
during suspend, or they haven't been switched on yet during resume).
For this reason, although it may seem that cpufreq_suspend() and
cpufreq_resume() are executed for all CPUs in the system, they are
only called for the boot CPU in fact, which is quite confusing.
To remove the confusion and to prepare for elimiating sysdev
suspend and resume operations from the kernel enirely, convernt
cpufreq to using a struct syscore_ops object for the boot CPU
suspend and resume and rename the callbacks so that their names
reflect their purpose. In addition, put some explanatory remarks
into their kerneldoc comments.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
2011-03-24 05:16:32 +08:00
|
|
|
};
|
|
|
|
|
2005-04-29 22:40:12 +08:00
|
|
|
/**
|
cpufreq: Use syscore_ops for boot CPU suspend/resume (v2)
The cpufreq subsystem uses sysdev suspend and resume for
executing cpufreq_suspend() and cpufreq_resume(), respectively,
during system suspend, after interrupts have been switched off on the
boot CPU, and during system resume, while interrupts are still off on
the boot CPU. In both cases the other CPUs are off-line at the
relevant point (either they have been switched off via CPU hotplug
during suspend, or they haven't been switched on yet during resume).
For this reason, although it may seem that cpufreq_suspend() and
cpufreq_resume() are executed for all CPUs in the system, they are
only called for the boot CPU in fact, which is quite confusing.
To remove the confusion and to prepare for elimiating sysdev
suspend and resume operations from the kernel enirely, convernt
cpufreq to using a struct syscore_ops object for the boot CPU
suspend and resume and rename the callbacks so that their names
reflect their purpose. In addition, put some explanatory remarks
into their kerneldoc comments.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
2011-03-24 05:16:32 +08:00
|
|
|
* cpufreq_bp_suspend - Prepare the boot CPU for system suspend.
|
|
|
|
*
|
|
|
|
* This function is only executed for the boot processor. The other CPUs
|
|
|
|
* have been put offline by means of CPU hotplug.
|
2005-04-29 22:40:12 +08:00
|
|
|
*/
|
cpufreq: Use syscore_ops for boot CPU suspend/resume (v2)
The cpufreq subsystem uses sysdev suspend and resume for
executing cpufreq_suspend() and cpufreq_resume(), respectively,
during system suspend, after interrupts have been switched off on the
boot CPU, and during system resume, while interrupts are still off on
the boot CPU. In both cases the other CPUs are off-line at the
relevant point (either they have been switched off via CPU hotplug
during suspend, or they haven't been switched on yet during resume).
For this reason, although it may seem that cpufreq_suspend() and
cpufreq_resume() are executed for all CPUs in the system, they are
only called for the boot CPU in fact, which is quite confusing.
To remove the confusion and to prepare for elimiating sysdev
suspend and resume operations from the kernel enirely, convernt
cpufreq to using a struct syscore_ops object for the boot CPU
suspend and resume and rename the callbacks so that their names
reflect their purpose. In addition, put some explanatory remarks
into their kerneldoc comments.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
2011-03-24 05:16:32 +08:00
|
|
|
static int cpufreq_bp_suspend(void)
|
2005-04-29 22:40:12 +08:00
|
|
|
{
|
2006-10-26 18:50:58 +08:00
|
|
|
int ret = 0;
|
2009-08-05 02:03:25 +08:00
|
|
|
|
cpufreq: Use syscore_ops for boot CPU suspend/resume (v2)
The cpufreq subsystem uses sysdev suspend and resume for
executing cpufreq_suspend() and cpufreq_resume(), respectively,
during system suspend, after interrupts have been switched off on the
boot CPU, and during system resume, while interrupts are still off on
the boot CPU. In both cases the other CPUs are off-line at the
relevant point (either they have been switched off via CPU hotplug
during suspend, or they haven't been switched on yet during resume).
For this reason, although it may seem that cpufreq_suspend() and
cpufreq_resume() are executed for all CPUs in the system, they are
only called for the boot CPU in fact, which is quite confusing.
To remove the confusion and to prepare for elimiating sysdev
suspend and resume operations from the kernel enirely, convernt
cpufreq to using a struct syscore_ops object for the boot CPU
suspend and resume and rename the callbacks so that their names
reflect their purpose. In addition, put some explanatory remarks
into their kerneldoc comments.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
2011-03-24 05:16:32 +08:00
|
|
|
int cpu = smp_processor_id();
|
2013-08-07 01:23:05 +08:00
|
|
|
struct cpufreq_policy *policy;
|
2005-04-29 22:40:12 +08:00
|
|
|
|
2011-03-27 21:04:46 +08:00
|
|
|
pr_debug("suspending cpu %u\n", cpu);
|
2005-04-29 22:40:12 +08:00
|
|
|
|
cpufreq: Use syscore_ops for boot CPU suspend/resume (v2)
The cpufreq subsystem uses sysdev suspend and resume for
executing cpufreq_suspend() and cpufreq_resume(), respectively,
during system suspend, after interrupts have been switched off on the
boot CPU, and during system resume, while interrupts are still off on
the boot CPU. In both cases the other CPUs are off-line at the
relevant point (either they have been switched off via CPU hotplug
during suspend, or they haven't been switched on yet during resume).
For this reason, although it may seem that cpufreq_suspend() and
cpufreq_resume() are executed for all CPUs in the system, they are
only called for the boot CPU in fact, which is quite confusing.
To remove the confusion and to prepare for elimiating sysdev
suspend and resume operations from the kernel enirely, convernt
cpufreq to using a struct syscore_ops object for the boot CPU
suspend and resume and rename the callbacks so that their names
reflect their purpose. In addition, put some explanatory remarks
into their kerneldoc comments.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
2011-03-24 05:16:32 +08:00
|
|
|
/* If there's no policy for the boot CPU, we have nothing to do. */
|
2013-08-07 01:23:05 +08:00
|
|
|
policy = cpufreq_cpu_get(cpu);
|
|
|
|
if (!policy)
|
cpufreq: Use syscore_ops for boot CPU suspend/resume (v2)
The cpufreq subsystem uses sysdev suspend and resume for
executing cpufreq_suspend() and cpufreq_resume(), respectively,
during system suspend, after interrupts have been switched off on the
boot CPU, and during system resume, while interrupts are still off on
the boot CPU. In both cases the other CPUs are off-line at the
relevant point (either they have been switched off via CPU hotplug
during suspend, or they haven't been switched on yet during resume).
For this reason, although it may seem that cpufreq_suspend() and
cpufreq_resume() are executed for all CPUs in the system, they are
only called for the boot CPU in fact, which is quite confusing.
To remove the confusion and to prepare for elimiating sysdev
suspend and resume operations from the kernel enirely, convernt
cpufreq to using a struct syscore_ops object for the boot CPU
suspend and resume and rename the callbacks so that their names
reflect their purpose. In addition, put some explanatory remarks
into their kerneldoc comments.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
2011-03-24 05:16:32 +08:00
|
|
|
return 0;
|
2005-04-29 22:40:12 +08:00
|
|
|
|
2013-04-29 06:08:16 +08:00
|
|
|
if (cpufreq_driver->suspend) {
|
2013-08-07 01:23:05 +08:00
|
|
|
ret = cpufreq_driver->suspend(policy);
|
[CPUFREQ] Re-enable cpufreq suspend and resume code
Commit 4bc5d3413503 is broken and causes regressions:
(1) cpufreq_driver->resume() and ->suspend() were only called on
__powerpc__, but you could set them on all architectures. In fact,
->resume() was defined and used before the PPC-related commit
42d4dc3f4e1e complained about in 4bc5d3413503.
(2) Therfore, the resume functions in acpi_cpufreq and speedstep-smi
would never be called.
(3) This means speedstep-smi would be unusuable after suspend or resume.
The _real_ problem was calling cpufreq_driver->get() with interrupts
off, but it re-enabling interrupts on some platforms. Why is ->get()
necessary?
Some systems like to change the CPU frequency behind our
back, especially during BIOS-intensive operations like suspend or
resume. If such systems also use a CPU frequency-dependant timing loop,
delays might be off by large factors. Therefore, we need to ascertain
as soon as possible that the CPU frequency is indeed at the speed we
think it is. You can do this two ways: either setting it anew, or trying
to get it. The latter is what was done, the former also has the same IRQ
issue.
So, let's try something different: defer the checking to after interrupts
are re-enabled, by calling cpufreq_update_policy() (via schedule_work()).
Timings may be off until this later stage, so let's watch out for
resume regressions caused by the deferred handling of frequency changes
behind the kernel's back.
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
Signed-off-by: Dave Jones <davej@redhat.com>
2009-08-08 04:58:51 +08:00
|
|
|
if (ret)
|
2005-04-29 22:40:12 +08:00
|
|
|
printk(KERN_ERR "cpufreq: suspend failed in ->suspend "
|
2013-08-07 01:23:05 +08:00
|
|
|
"step on CPU %u\n", policy->cpu);
|
2005-04-29 22:40:12 +08:00
|
|
|
}
|
|
|
|
|
2013-08-07 01:23:05 +08:00
|
|
|
cpufreq_cpu_put(policy);
|
2008-02-08 05:32:18 +08:00
|
|
|
return ret;
|
2005-04-29 22:40:12 +08:00
|
|
|
}
|
|
|
|
|
2005-04-17 06:20:36 +08:00
|
|
|
/**
|
cpufreq: Use syscore_ops for boot CPU suspend/resume (v2)
The cpufreq subsystem uses sysdev suspend and resume for
executing cpufreq_suspend() and cpufreq_resume(), respectively,
during system suspend, after interrupts have been switched off on the
boot CPU, and during system resume, while interrupts are still off on
the boot CPU. In both cases the other CPUs are off-line at the
relevant point (either they have been switched off via CPU hotplug
during suspend, or they haven't been switched on yet during resume).
For this reason, although it may seem that cpufreq_suspend() and
cpufreq_resume() are executed for all CPUs in the system, they are
only called for the boot CPU in fact, which is quite confusing.
To remove the confusion and to prepare for elimiating sysdev
suspend and resume operations from the kernel enirely, convernt
cpufreq to using a struct syscore_ops object for the boot CPU
suspend and resume and rename the callbacks so that their names
reflect their purpose. In addition, put some explanatory remarks
into their kerneldoc comments.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
2011-03-24 05:16:32 +08:00
|
|
|
* cpufreq_bp_resume - Restore proper frequency handling of the boot CPU.
|
2005-04-17 06:20:36 +08:00
|
|
|
*
|
|
|
|
* 1.) resume CPUfreq hardware support (cpufreq_driver->resume())
|
[CPUFREQ] Re-enable cpufreq suspend and resume code
Commit 4bc5d3413503 is broken and causes regressions:
(1) cpufreq_driver->resume() and ->suspend() were only called on
__powerpc__, but you could set them on all architectures. In fact,
->resume() was defined and used before the PPC-related commit
42d4dc3f4e1e complained about in 4bc5d3413503.
(2) Therfore, the resume functions in acpi_cpufreq and speedstep-smi
would never be called.
(3) This means speedstep-smi would be unusuable after suspend or resume.
The _real_ problem was calling cpufreq_driver->get() with interrupts
off, but it re-enabling interrupts on some platforms. Why is ->get()
necessary?
Some systems like to change the CPU frequency behind our
back, especially during BIOS-intensive operations like suspend or
resume. If such systems also use a CPU frequency-dependant timing loop,
delays might be off by large factors. Therefore, we need to ascertain
as soon as possible that the CPU frequency is indeed at the speed we
think it is. You can do this two ways: either setting it anew, or trying
to get it. The latter is what was done, the former also has the same IRQ
issue.
So, let's try something different: defer the checking to after interrupts
are re-enabled, by calling cpufreq_update_policy() (via schedule_work()).
Timings may be off until this later stage, so let's watch out for
resume regressions caused by the deferred handling of frequency changes
behind the kernel's back.
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
Signed-off-by: Dave Jones <davej@redhat.com>
2009-08-08 04:58:51 +08:00
|
|
|
* 2.) schedule call cpufreq_update_policy() ASAP as interrupts are
|
|
|
|
* restored. It will verify that the current freq is in sync with
|
|
|
|
* what we believe it to be. This is a bit later than when it
|
|
|
|
* should be, but nonethteless it's better than calling
|
|
|
|
* cpufreq_driver->get() here which might re-enable interrupts...
|
cpufreq: Use syscore_ops for boot CPU suspend/resume (v2)
The cpufreq subsystem uses sysdev suspend and resume for
executing cpufreq_suspend() and cpufreq_resume(), respectively,
during system suspend, after interrupts have been switched off on the
boot CPU, and during system resume, while interrupts are still off on
the boot CPU. In both cases the other CPUs are off-line at the
relevant point (either they have been switched off via CPU hotplug
during suspend, or they haven't been switched on yet during resume).
For this reason, although it may seem that cpufreq_suspend() and
cpufreq_resume() are executed for all CPUs in the system, they are
only called for the boot CPU in fact, which is quite confusing.
To remove the confusion and to prepare for elimiating sysdev
suspend and resume operations from the kernel enirely, convernt
cpufreq to using a struct syscore_ops object for the boot CPU
suspend and resume and rename the callbacks so that their names
reflect their purpose. In addition, put some explanatory remarks
into their kerneldoc comments.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
2011-03-24 05:16:32 +08:00
|
|
|
*
|
|
|
|
* This function is only executed for the boot CPU. The other CPUs have not
|
|
|
|
* been turned on yet.
|
2005-04-17 06:20:36 +08:00
|
|
|
*/
|
cpufreq: Use syscore_ops for boot CPU suspend/resume (v2)
The cpufreq subsystem uses sysdev suspend and resume for
executing cpufreq_suspend() and cpufreq_resume(), respectively,
during system suspend, after interrupts have been switched off on the
boot CPU, and during system resume, while interrupts are still off on
the boot CPU. In both cases the other CPUs are off-line at the
relevant point (either they have been switched off via CPU hotplug
during suspend, or they haven't been switched on yet during resume).
For this reason, although it may seem that cpufreq_suspend() and
cpufreq_resume() are executed for all CPUs in the system, they are
only called for the boot CPU in fact, which is quite confusing.
To remove the confusion and to prepare for elimiating sysdev
suspend and resume operations from the kernel enirely, convernt
cpufreq to using a struct syscore_ops object for the boot CPU
suspend and resume and rename the callbacks so that their names
reflect their purpose. In addition, put some explanatory remarks
into their kerneldoc comments.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
2011-03-24 05:16:32 +08:00
|
|
|
static void cpufreq_bp_resume(void)
|
2005-04-17 06:20:36 +08:00
|
|
|
{
|
2006-10-26 18:50:58 +08:00
|
|
|
int ret = 0;
|
2009-08-05 02:03:25 +08:00
|
|
|
|
cpufreq: Use syscore_ops for boot CPU suspend/resume (v2)
The cpufreq subsystem uses sysdev suspend and resume for
executing cpufreq_suspend() and cpufreq_resume(), respectively,
during system suspend, after interrupts have been switched off on the
boot CPU, and during system resume, while interrupts are still off on
the boot CPU. In both cases the other CPUs are off-line at the
relevant point (either they have been switched off via CPU hotplug
during suspend, or they haven't been switched on yet during resume).
For this reason, although it may seem that cpufreq_suspend() and
cpufreq_resume() are executed for all CPUs in the system, they are
only called for the boot CPU in fact, which is quite confusing.
To remove the confusion and to prepare for elimiating sysdev
suspend and resume operations from the kernel enirely, convernt
cpufreq to using a struct syscore_ops object for the boot CPU
suspend and resume and rename the callbacks so that their names
reflect their purpose. In addition, put some explanatory remarks
into their kerneldoc comments.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
2011-03-24 05:16:32 +08:00
|
|
|
int cpu = smp_processor_id();
|
2013-08-07 01:23:05 +08:00
|
|
|
struct cpufreq_policy *policy;
|
2005-04-17 06:20:36 +08:00
|
|
|
|
2011-03-27 21:04:46 +08:00
|
|
|
pr_debug("resuming cpu %u\n", cpu);
|
2005-04-17 06:20:36 +08:00
|
|
|
|
cpufreq: Use syscore_ops for boot CPU suspend/resume (v2)
The cpufreq subsystem uses sysdev suspend and resume for
executing cpufreq_suspend() and cpufreq_resume(), respectively,
during system suspend, after interrupts have been switched off on the
boot CPU, and during system resume, while interrupts are still off on
the boot CPU. In both cases the other CPUs are off-line at the
relevant point (either they have been switched off via CPU hotplug
during suspend, or they haven't been switched on yet during resume).
For this reason, although it may seem that cpufreq_suspend() and
cpufreq_resume() are executed for all CPUs in the system, they are
only called for the boot CPU in fact, which is quite confusing.
To remove the confusion and to prepare for elimiating sysdev
suspend and resume operations from the kernel enirely, convernt
cpufreq to using a struct syscore_ops object for the boot CPU
suspend and resume and rename the callbacks so that their names
reflect their purpose. In addition, put some explanatory remarks
into their kerneldoc comments.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
2011-03-24 05:16:32 +08:00
|
|
|
/* If there's no policy for the boot CPU, we have nothing to do. */
|
2013-08-07 01:23:05 +08:00
|
|
|
policy = cpufreq_cpu_get(cpu);
|
|
|
|
if (!policy)
|
cpufreq: Use syscore_ops for boot CPU suspend/resume (v2)
The cpufreq subsystem uses sysdev suspend and resume for
executing cpufreq_suspend() and cpufreq_resume(), respectively,
during system suspend, after interrupts have been switched off on the
boot CPU, and during system resume, while interrupts are still off on
the boot CPU. In both cases the other CPUs are off-line at the
relevant point (either they have been switched off via CPU hotplug
during suspend, or they haven't been switched on yet during resume).
For this reason, although it may seem that cpufreq_suspend() and
cpufreq_resume() are executed for all CPUs in the system, they are
only called for the boot CPU in fact, which is quite confusing.
To remove the confusion and to prepare for elimiating sysdev
suspend and resume operations from the kernel enirely, convernt
cpufreq to using a struct syscore_ops object for the boot CPU
suspend and resume and rename the callbacks so that their names
reflect their purpose. In addition, put some explanatory remarks
into their kerneldoc comments.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
2011-03-24 05:16:32 +08:00
|
|
|
return;
|
2005-04-17 06:20:36 +08:00
|
|
|
|
2013-04-29 06:08:16 +08:00
|
|
|
if (cpufreq_driver->resume) {
|
2013-08-07 01:23:05 +08:00
|
|
|
ret = cpufreq_driver->resume(policy);
|
2005-04-17 06:20:36 +08:00
|
|
|
if (ret) {
|
|
|
|
printk(KERN_ERR "cpufreq: resume failed in ->resume "
|
2013-08-07 01:23:05 +08:00
|
|
|
"step on CPU %u\n", policy->cpu);
|
2008-02-08 05:32:18 +08:00
|
|
|
goto fail;
|
2005-04-17 06:20:36 +08:00
|
|
|
}
|
|
|
|
}
|
|
|
|
|
2013-08-07 01:23:05 +08:00
|
|
|
schedule_work(&policy->update);
|
[CPUFREQ] Re-enable cpufreq suspend and resume code
Commit 4bc5d3413503 is broken and causes regressions:
(1) cpufreq_driver->resume() and ->suspend() were only called on
__powerpc__, but you could set them on all architectures. In fact,
->resume() was defined and used before the PPC-related commit
42d4dc3f4e1e complained about in 4bc5d3413503.
(2) Therfore, the resume functions in acpi_cpufreq and speedstep-smi
would never be called.
(3) This means speedstep-smi would be unusuable after suspend or resume.
The _real_ problem was calling cpufreq_driver->get() with interrupts
off, but it re-enabling interrupts on some platforms. Why is ->get()
necessary?
Some systems like to change the CPU frequency behind our
back, especially during BIOS-intensive operations like suspend or
resume. If such systems also use a CPU frequency-dependant timing loop,
delays might be off by large factors. Therefore, we need to ascertain
as soon as possible that the CPU frequency is indeed at the speed we
think it is. You can do this two ways: either setting it anew, or trying
to get it. The latter is what was done, the former also has the same IRQ
issue.
So, let's try something different: defer the checking to after interrupts
are re-enabled, by calling cpufreq_update_policy() (via schedule_work()).
Timings may be off until this later stage, so let's watch out for
resume regressions caused by the deferred handling of frequency changes
behind the kernel's back.
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
Signed-off-by: Dave Jones <davej@redhat.com>
2009-08-08 04:58:51 +08:00
|
|
|
|
2008-02-08 05:32:18 +08:00
|
|
|
fail:
|
2013-08-07 01:23:05 +08:00
|
|
|
cpufreq_cpu_put(policy);
|
2005-04-17 06:20:36 +08:00
|
|
|
}
|
|
|
|
|
cpufreq: Use syscore_ops for boot CPU suspend/resume (v2)
The cpufreq subsystem uses sysdev suspend and resume for
executing cpufreq_suspend() and cpufreq_resume(), respectively,
during system suspend, after interrupts have been switched off on the
boot CPU, and during system resume, while interrupts are still off on
the boot CPU. In both cases the other CPUs are off-line at the
relevant point (either they have been switched off via CPU hotplug
during suspend, or they haven't been switched on yet during resume).
For this reason, although it may seem that cpufreq_suspend() and
cpufreq_resume() are executed for all CPUs in the system, they are
only called for the boot CPU in fact, which is quite confusing.
To remove the confusion and to prepare for elimiating sysdev
suspend and resume operations from the kernel enirely, convernt
cpufreq to using a struct syscore_ops object for the boot CPU
suspend and resume and rename the callbacks so that their names
reflect their purpose. In addition, put some explanatory remarks
into their kerneldoc comments.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
2011-03-24 05:16:32 +08:00
|
|
|
static struct syscore_ops cpufreq_syscore_ops = {
|
|
|
|
.suspend = cpufreq_bp_suspend,
|
|
|
|
.resume = cpufreq_bp_resume,
|
2005-04-17 06:20:36 +08:00
|
|
|
};
|
|
|
|
|
2013-01-20 18:24:28 +08:00
|
|
|
/**
|
|
|
|
* cpufreq_get_current_driver - return current driver's name
|
|
|
|
*
|
|
|
|
* Return the name string of the currently loaded cpufreq driver
|
|
|
|
* or NULL, if none.
|
|
|
|
*/
|
|
|
|
const char *cpufreq_get_current_driver(void)
|
|
|
|
{
|
2013-04-29 06:08:16 +08:00
|
|
|
if (cpufreq_driver)
|
|
|
|
return cpufreq_driver->name;
|
|
|
|
|
|
|
|
return NULL;
|
2013-01-20 18:24:28 +08:00
|
|
|
}
|
|
|
|
EXPORT_SYMBOL_GPL(cpufreq_get_current_driver);
|
2005-04-17 06:20:36 +08:00
|
|
|
|
|
|
|
/*********************************************************************
|
|
|
|
* NOTIFIER LISTS INTERFACE *
|
|
|
|
*********************************************************************/
|
|
|
|
|
|
|
|
/**
|
|
|
|
* cpufreq_register_notifier - register a driver with cpufreq
|
|
|
|
* @nb: notifier function to register
|
|
|
|
* @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER
|
|
|
|
*
|
2006-02-28 13:43:23 +08:00
|
|
|
* Add a driver to one of two lists: either a list of drivers that
|
2005-04-17 06:20:36 +08:00
|
|
|
* are notified about clock rate changes (once before and once after
|
|
|
|
* the transition), or a list of drivers that are notified about
|
|
|
|
* changes in cpufreq policy.
|
|
|
|
*
|
|
|
|
* This function may sleep, and has the same return conditions as
|
[PATCH] Notifier chain update: API changes
The kernel's implementation of notifier chains is unsafe. There is no
protection against entries being added to or removed from a chain while the
chain is in use. The issues were discussed in this thread:
http://marc.theaimsgroup.com/?l=linux-kernel&m=113018709002036&w=2
We noticed that notifier chains in the kernel fall into two basic usage
classes:
"Blocking" chains are always called from a process context
and the callout routines are allowed to sleep;
"Atomic" chains can be called from an atomic context and
the callout routines are not allowed to sleep.
We decided to codify this distinction and make it part of the API. Therefore
this set of patches introduces three new, parallel APIs: one for blocking
notifiers, one for atomic notifiers, and one for "raw" notifiers (which is
really just the old API under a new name). New kinds of data structures are
used for the heads of the chains, and new routines are defined for
registration, unregistration, and calling a chain. The three APIs are
explained in include/linux/notifier.h and their implementation is in
kernel/sys.c.
With atomic and blocking chains, the implementation guarantees that the chain
links will not be corrupted and that chain callers will not get messed up by
entries being added or removed. For raw chains the implementation provides no
guarantees at all; users of this API must provide their own protections. (The
idea was that situations may come up where the assumptions of the atomic and
blocking APIs are not appropriate, so it should be possible for users to
handle these things in their own way.)
There are some limitations, which should not be too hard to live with. For
atomic/blocking chains, registration and unregistration must always be done in
a process context since the chain is protected by a mutex/rwsem. Also, a
callout routine for a non-raw chain must not try to register or unregister
entries on its own chain. (This did happen in a couple of places and the code
had to be changed to avoid it.)
Since atomic chains may be called from within an NMI handler, they cannot use
spinlocks for synchronization. Instead we use RCU. The overhead falls almost
entirely in the unregister routine, which is okay since unregistration is much
less frequent that calling a chain.
Here is the list of chains that we adjusted and their classifications. None
of them use the raw API, so for the moment it is only a placeholder.
ATOMIC CHAINS
-------------
arch/i386/kernel/traps.c: i386die_chain
arch/ia64/kernel/traps.c: ia64die_chain
arch/powerpc/kernel/traps.c: powerpc_die_chain
arch/sparc64/kernel/traps.c: sparc64die_chain
arch/x86_64/kernel/traps.c: die_chain
drivers/char/ipmi/ipmi_si_intf.c: xaction_notifier_list
kernel/panic.c: panic_notifier_list
kernel/profile.c: task_free_notifier
net/bluetooth/hci_core.c: hci_notifier
net/ipv4/netfilter/ip_conntrack_core.c: ip_conntrack_chain
net/ipv4/netfilter/ip_conntrack_core.c: ip_conntrack_expect_chain
net/ipv6/addrconf.c: inet6addr_chain
net/netfilter/nf_conntrack_core.c: nf_conntrack_chain
net/netfilter/nf_conntrack_core.c: nf_conntrack_expect_chain
net/netlink/af_netlink.c: netlink_chain
BLOCKING CHAINS
---------------
arch/powerpc/platforms/pseries/reconfig.c: pSeries_reconfig_chain
arch/s390/kernel/process.c: idle_chain
arch/x86_64/kernel/process.c idle_notifier
drivers/base/memory.c: memory_chain
drivers/cpufreq/cpufreq.c cpufreq_policy_notifier_list
drivers/cpufreq/cpufreq.c cpufreq_transition_notifier_list
drivers/macintosh/adb.c: adb_client_list
drivers/macintosh/via-pmu.c sleep_notifier_list
drivers/macintosh/via-pmu68k.c sleep_notifier_list
drivers/macintosh/windfarm_core.c wf_client_list
drivers/usb/core/notify.c usb_notifier_list
drivers/video/fbmem.c fb_notifier_list
kernel/cpu.c cpu_chain
kernel/module.c module_notify_list
kernel/profile.c munmap_notifier
kernel/profile.c task_exit_notifier
kernel/sys.c reboot_notifier_list
net/core/dev.c netdev_chain
net/decnet/dn_dev.c: dnaddr_chain
net/ipv4/devinet.c: inetaddr_chain
It's possible that some of these classifications are wrong. If they are,
please let us know or submit a patch to fix them. Note that any chain that
gets called very frequently should be atomic, because the rwsem read-locking
used for blocking chains is very likely to incur cache misses on SMP systems.
(However, if the chain's callout routines may sleep then the chain cannot be
atomic.)
The patch set was written by Alan Stern and Chandra Seetharaman, incorporating
material written by Keith Owens and suggestions from Paul McKenney and Andrew
Morton.
[jes@sgi.com: restructure the notifier chain initialization macros]
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Chandra Seetharaman <sekharan@us.ibm.com>
Signed-off-by: Jes Sorensen <jes@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-03-27 17:16:30 +08:00
|
|
|
* blocking_notifier_chain_register.
|
2005-04-17 06:20:36 +08:00
|
|
|
*/
|
|
|
|
int cpufreq_register_notifier(struct notifier_block *nb, unsigned int list)
|
|
|
|
{
|
|
|
|
int ret;
|
|
|
|
|
2013-01-18 00:22:21 +08:00
|
|
|
if (cpufreq_disabled())
|
|
|
|
return -EINVAL;
|
|
|
|
|
2008-02-16 18:41:24 +08:00
|
|
|
WARN_ON(!init_cpufreq_transition_notifier_list_called);
|
|
|
|
|
2005-04-17 06:20:36 +08:00
|
|
|
switch (list) {
|
|
|
|
case CPUFREQ_TRANSITION_NOTIFIER:
|
2006-10-04 17:17:06 +08:00
|
|
|
ret = srcu_notifier_chain_register(
|
[PATCH] Notifier chain update: API changes
The kernel's implementation of notifier chains is unsafe. There is no
protection against entries being added to or removed from a chain while the
chain is in use. The issues were discussed in this thread:
http://marc.theaimsgroup.com/?l=linux-kernel&m=113018709002036&w=2
We noticed that notifier chains in the kernel fall into two basic usage
classes:
"Blocking" chains are always called from a process context
and the callout routines are allowed to sleep;
"Atomic" chains can be called from an atomic context and
the callout routines are not allowed to sleep.
We decided to codify this distinction and make it part of the API. Therefore
this set of patches introduces three new, parallel APIs: one for blocking
notifiers, one for atomic notifiers, and one for "raw" notifiers (which is
really just the old API under a new name). New kinds of data structures are
used for the heads of the chains, and new routines are defined for
registration, unregistration, and calling a chain. The three APIs are
explained in include/linux/notifier.h and their implementation is in
kernel/sys.c.
With atomic and blocking chains, the implementation guarantees that the chain
links will not be corrupted and that chain callers will not get messed up by
entries being added or removed. For raw chains the implementation provides no
guarantees at all; users of this API must provide their own protections. (The
idea was that situations may come up where the assumptions of the atomic and
blocking APIs are not appropriate, so it should be possible for users to
handle these things in their own way.)
There are some limitations, which should not be too hard to live with. For
atomic/blocking chains, registration and unregistration must always be done in
a process context since the chain is protected by a mutex/rwsem. Also, a
callout routine for a non-raw chain must not try to register or unregister
entries on its own chain. (This did happen in a couple of places and the code
had to be changed to avoid it.)
Since atomic chains may be called from within an NMI handler, they cannot use
spinlocks for synchronization. Instead we use RCU. The overhead falls almost
entirely in the unregister routine, which is okay since unregistration is much
less frequent that calling a chain.
Here is the list of chains that we adjusted and their classifications. None
of them use the raw API, so for the moment it is only a placeholder.
ATOMIC CHAINS
-------------
arch/i386/kernel/traps.c: i386die_chain
arch/ia64/kernel/traps.c: ia64die_chain
arch/powerpc/kernel/traps.c: powerpc_die_chain
arch/sparc64/kernel/traps.c: sparc64die_chain
arch/x86_64/kernel/traps.c: die_chain
drivers/char/ipmi/ipmi_si_intf.c: xaction_notifier_list
kernel/panic.c: panic_notifier_list
kernel/profile.c: task_free_notifier
net/bluetooth/hci_core.c: hci_notifier
net/ipv4/netfilter/ip_conntrack_core.c: ip_conntrack_chain
net/ipv4/netfilter/ip_conntrack_core.c: ip_conntrack_expect_chain
net/ipv6/addrconf.c: inet6addr_chain
net/netfilter/nf_conntrack_core.c: nf_conntrack_chain
net/netfilter/nf_conntrack_core.c: nf_conntrack_expect_chain
net/netlink/af_netlink.c: netlink_chain
BLOCKING CHAINS
---------------
arch/powerpc/platforms/pseries/reconfig.c: pSeries_reconfig_chain
arch/s390/kernel/process.c: idle_chain
arch/x86_64/kernel/process.c idle_notifier
drivers/base/memory.c: memory_chain
drivers/cpufreq/cpufreq.c cpufreq_policy_notifier_list
drivers/cpufreq/cpufreq.c cpufreq_transition_notifier_list
drivers/macintosh/adb.c: adb_client_list
drivers/macintosh/via-pmu.c sleep_notifier_list
drivers/macintosh/via-pmu68k.c sleep_notifier_list
drivers/macintosh/windfarm_core.c wf_client_list
drivers/usb/core/notify.c usb_notifier_list
drivers/video/fbmem.c fb_notifier_list
kernel/cpu.c cpu_chain
kernel/module.c module_notify_list
kernel/profile.c munmap_notifier
kernel/profile.c task_exit_notifier
kernel/sys.c reboot_notifier_list
net/core/dev.c netdev_chain
net/decnet/dn_dev.c: dnaddr_chain
net/ipv4/devinet.c: inetaddr_chain
It's possible that some of these classifications are wrong. If they are,
please let us know or submit a patch to fix them. Note that any chain that
gets called very frequently should be atomic, because the rwsem read-locking
used for blocking chains is very likely to incur cache misses on SMP systems.
(However, if the chain's callout routines may sleep then the chain cannot be
atomic.)
The patch set was written by Alan Stern and Chandra Seetharaman, incorporating
material written by Keith Owens and suggestions from Paul McKenney and Andrew
Morton.
[jes@sgi.com: restructure the notifier chain initialization macros]
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Chandra Seetharaman <sekharan@us.ibm.com>
Signed-off-by: Jes Sorensen <jes@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-03-27 17:16:30 +08:00
|
|
|
&cpufreq_transition_notifier_list, nb);
|
2005-04-17 06:20:36 +08:00
|
|
|
break;
|
|
|
|
case CPUFREQ_POLICY_NOTIFIER:
|
[PATCH] Notifier chain update: API changes
The kernel's implementation of notifier chains is unsafe. There is no
protection against entries being added to or removed from a chain while the
chain is in use. The issues were discussed in this thread:
http://marc.theaimsgroup.com/?l=linux-kernel&m=113018709002036&w=2
We noticed that notifier chains in the kernel fall into two basic usage
classes:
"Blocking" chains are always called from a process context
and the callout routines are allowed to sleep;
"Atomic" chains can be called from an atomic context and
the callout routines are not allowed to sleep.
We decided to codify this distinction and make it part of the API. Therefore
this set of patches introduces three new, parallel APIs: one for blocking
notifiers, one for atomic notifiers, and one for "raw" notifiers (which is
really just the old API under a new name). New kinds of data structures are
used for the heads of the chains, and new routines are defined for
registration, unregistration, and calling a chain. The three APIs are
explained in include/linux/notifier.h and their implementation is in
kernel/sys.c.
With atomic and blocking chains, the implementation guarantees that the chain
links will not be corrupted and that chain callers will not get messed up by
entries being added or removed. For raw chains the implementation provides no
guarantees at all; users of this API must provide their own protections. (The
idea was that situations may come up where the assumptions of the atomic and
blocking APIs are not appropriate, so it should be possible for users to
handle these things in their own way.)
There are some limitations, which should not be too hard to live with. For
atomic/blocking chains, registration and unregistration must always be done in
a process context since the chain is protected by a mutex/rwsem. Also, a
callout routine for a non-raw chain must not try to register or unregister
entries on its own chain. (This did happen in a couple of places and the code
had to be changed to avoid it.)
Since atomic chains may be called from within an NMI handler, they cannot use
spinlocks for synchronization. Instead we use RCU. The overhead falls almost
entirely in the unregister routine, which is okay since unregistration is much
less frequent that calling a chain.
Here is the list of chains that we adjusted and their classifications. None
of them use the raw API, so for the moment it is only a placeholder.
ATOMIC CHAINS
-------------
arch/i386/kernel/traps.c: i386die_chain
arch/ia64/kernel/traps.c: ia64die_chain
arch/powerpc/kernel/traps.c: powerpc_die_chain
arch/sparc64/kernel/traps.c: sparc64die_chain
arch/x86_64/kernel/traps.c: die_chain
drivers/char/ipmi/ipmi_si_intf.c: xaction_notifier_list
kernel/panic.c: panic_notifier_list
kernel/profile.c: task_free_notifier
net/bluetooth/hci_core.c: hci_notifier
net/ipv4/netfilter/ip_conntrack_core.c: ip_conntrack_chain
net/ipv4/netfilter/ip_conntrack_core.c: ip_conntrack_expect_chain
net/ipv6/addrconf.c: inet6addr_chain
net/netfilter/nf_conntrack_core.c: nf_conntrack_chain
net/netfilter/nf_conntrack_core.c: nf_conntrack_expect_chain
net/netlink/af_netlink.c: netlink_chain
BLOCKING CHAINS
---------------
arch/powerpc/platforms/pseries/reconfig.c: pSeries_reconfig_chain
arch/s390/kernel/process.c: idle_chain
arch/x86_64/kernel/process.c idle_notifier
drivers/base/memory.c: memory_chain
drivers/cpufreq/cpufreq.c cpufreq_policy_notifier_list
drivers/cpufreq/cpufreq.c cpufreq_transition_notifier_list
drivers/macintosh/adb.c: adb_client_list
drivers/macintosh/via-pmu.c sleep_notifier_list
drivers/macintosh/via-pmu68k.c sleep_notifier_list
drivers/macintosh/windfarm_core.c wf_client_list
drivers/usb/core/notify.c usb_notifier_list
drivers/video/fbmem.c fb_notifier_list
kernel/cpu.c cpu_chain
kernel/module.c module_notify_list
kernel/profile.c munmap_notifier
kernel/profile.c task_exit_notifier
kernel/sys.c reboot_notifier_list
net/core/dev.c netdev_chain
net/decnet/dn_dev.c: dnaddr_chain
net/ipv4/devinet.c: inetaddr_chain
It's possible that some of these classifications are wrong. If they are,
please let us know or submit a patch to fix them. Note that any chain that
gets called very frequently should be atomic, because the rwsem read-locking
used for blocking chains is very likely to incur cache misses on SMP systems.
(However, if the chain's callout routines may sleep then the chain cannot be
atomic.)
The patch set was written by Alan Stern and Chandra Seetharaman, incorporating
material written by Keith Owens and suggestions from Paul McKenney and Andrew
Morton.
[jes@sgi.com: restructure the notifier chain initialization macros]
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Chandra Seetharaman <sekharan@us.ibm.com>
Signed-off-by: Jes Sorensen <jes@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-03-27 17:16:30 +08:00
|
|
|
ret = blocking_notifier_chain_register(
|
|
|
|
&cpufreq_policy_notifier_list, nb);
|
2005-04-17 06:20:36 +08:00
|
|
|
break;
|
|
|
|
default:
|
|
|
|
ret = -EINVAL;
|
|
|
|
}
|
|
|
|
|
|
|
|
return ret;
|
|
|
|
}
|
|
|
|
EXPORT_SYMBOL(cpufreq_register_notifier);
|
|
|
|
|
|
|
|
/**
|
|
|
|
* cpufreq_unregister_notifier - unregister a driver with cpufreq
|
|
|
|
* @nb: notifier block to be unregistered
|
2013-06-19 16:49:33 +08:00
|
|
|
* @list: CPUFREQ_TRANSITION_NOTIFIER or CPUFREQ_POLICY_NOTIFIER
|
2005-04-17 06:20:36 +08:00
|
|
|
*
|
|
|
|
* Remove a driver from the CPU frequency notifier list.
|
|
|
|
*
|
|
|
|
* This function may sleep, and has the same return conditions as
|
[PATCH] Notifier chain update: API changes
The kernel's implementation of notifier chains is unsafe. There is no
protection against entries being added to or removed from a chain while the
chain is in use. The issues were discussed in this thread:
http://marc.theaimsgroup.com/?l=linux-kernel&m=113018709002036&w=2
We noticed that notifier chains in the kernel fall into two basic usage
classes:
"Blocking" chains are always called from a process context
and the callout routines are allowed to sleep;
"Atomic" chains can be called from an atomic context and
the callout routines are not allowed to sleep.
We decided to codify this distinction and make it part of the API. Therefore
this set of patches introduces three new, parallel APIs: one for blocking
notifiers, one for atomic notifiers, and one for "raw" notifiers (which is
really just the old API under a new name). New kinds of data structures are
used for the heads of the chains, and new routines are defined for
registration, unregistration, and calling a chain. The three APIs are
explained in include/linux/notifier.h and their implementation is in
kernel/sys.c.
With atomic and blocking chains, the implementation guarantees that the chain
links will not be corrupted and that chain callers will not get messed up by
entries being added or removed. For raw chains the implementation provides no
guarantees at all; users of this API must provide their own protections. (The
idea was that situations may come up where the assumptions of the atomic and
blocking APIs are not appropriate, so it should be possible for users to
handle these things in their own way.)
There are some limitations, which should not be too hard to live with. For
atomic/blocking chains, registration and unregistration must always be done in
a process context since the chain is protected by a mutex/rwsem. Also, a
callout routine for a non-raw chain must not try to register or unregister
entries on its own chain. (This did happen in a couple of places and the code
had to be changed to avoid it.)
Since atomic chains may be called from within an NMI handler, they cannot use
spinlocks for synchronization. Instead we use RCU. The overhead falls almost
entirely in the unregister routine, which is okay since unregistration is much
less frequent that calling a chain.
Here is the list of chains that we adjusted and their classifications. None
of them use the raw API, so for the moment it is only a placeholder.
ATOMIC CHAINS
-------------
arch/i386/kernel/traps.c: i386die_chain
arch/ia64/kernel/traps.c: ia64die_chain
arch/powerpc/kernel/traps.c: powerpc_die_chain
arch/sparc64/kernel/traps.c: sparc64die_chain
arch/x86_64/kernel/traps.c: die_chain
drivers/char/ipmi/ipmi_si_intf.c: xaction_notifier_list
kernel/panic.c: panic_notifier_list
kernel/profile.c: task_free_notifier
net/bluetooth/hci_core.c: hci_notifier
net/ipv4/netfilter/ip_conntrack_core.c: ip_conntrack_chain
net/ipv4/netfilter/ip_conntrack_core.c: ip_conntrack_expect_chain
net/ipv6/addrconf.c: inet6addr_chain
net/netfilter/nf_conntrack_core.c: nf_conntrack_chain
net/netfilter/nf_conntrack_core.c: nf_conntrack_expect_chain
net/netlink/af_netlink.c: netlink_chain
BLOCKING CHAINS
---------------
arch/powerpc/platforms/pseries/reconfig.c: pSeries_reconfig_chain
arch/s390/kernel/process.c: idle_chain
arch/x86_64/kernel/process.c idle_notifier
drivers/base/memory.c: memory_chain
drivers/cpufreq/cpufreq.c cpufreq_policy_notifier_list
drivers/cpufreq/cpufreq.c cpufreq_transition_notifier_list
drivers/macintosh/adb.c: adb_client_list
drivers/macintosh/via-pmu.c sleep_notifier_list
drivers/macintosh/via-pmu68k.c sleep_notifier_list
drivers/macintosh/windfarm_core.c wf_client_list
drivers/usb/core/notify.c usb_notifier_list
drivers/video/fbmem.c fb_notifier_list
kernel/cpu.c cpu_chain
kernel/module.c module_notify_list
kernel/profile.c munmap_notifier
kernel/profile.c task_exit_notifier
kernel/sys.c reboot_notifier_list
net/core/dev.c netdev_chain
net/decnet/dn_dev.c: dnaddr_chain
net/ipv4/devinet.c: inetaddr_chain
It's possible that some of these classifications are wrong. If they are,
please let us know or submit a patch to fix them. Note that any chain that
gets called very frequently should be atomic, because the rwsem read-locking
used for blocking chains is very likely to incur cache misses on SMP systems.
(However, if the chain's callout routines may sleep then the chain cannot be
atomic.)
The patch set was written by Alan Stern and Chandra Seetharaman, incorporating
material written by Keith Owens and suggestions from Paul McKenney and Andrew
Morton.
[jes@sgi.com: restructure the notifier chain initialization macros]
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Chandra Seetharaman <sekharan@us.ibm.com>
Signed-off-by: Jes Sorensen <jes@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-03-27 17:16:30 +08:00
|
|
|
* blocking_notifier_chain_unregister.
|
2005-04-17 06:20:36 +08:00
|
|
|
*/
|
|
|
|
int cpufreq_unregister_notifier(struct notifier_block *nb, unsigned int list)
|
|
|
|
{
|
|
|
|
int ret;
|
|
|
|
|
2013-01-18 00:22:21 +08:00
|
|
|
if (cpufreq_disabled())
|
|
|
|
return -EINVAL;
|
|
|
|
|
2005-04-17 06:20:36 +08:00
|
|
|
switch (list) {
|
|
|
|
case CPUFREQ_TRANSITION_NOTIFIER:
|
2006-10-04 17:17:06 +08:00
|
|
|
ret = srcu_notifier_chain_unregister(
|
[PATCH] Notifier chain update: API changes
The kernel's implementation of notifier chains is unsafe. There is no
protection against entries being added to or removed from a chain while the
chain is in use. The issues were discussed in this thread:
http://marc.theaimsgroup.com/?l=linux-kernel&m=113018709002036&w=2
We noticed that notifier chains in the kernel fall into two basic usage
classes:
"Blocking" chains are always called from a process context
and the callout routines are allowed to sleep;
"Atomic" chains can be called from an atomic context and
the callout routines are not allowed to sleep.
We decided to codify this distinction and make it part of the API. Therefore
this set of patches introduces three new, parallel APIs: one for blocking
notifiers, one for atomic notifiers, and one for "raw" notifiers (which is
really just the old API under a new name). New kinds of data structures are
used for the heads of the chains, and new routines are defined for
registration, unregistration, and calling a chain. The three APIs are
explained in include/linux/notifier.h and their implementation is in
kernel/sys.c.
With atomic and blocking chains, the implementation guarantees that the chain
links will not be corrupted and that chain callers will not get messed up by
entries being added or removed. For raw chains the implementation provides no
guarantees at all; users of this API must provide their own protections. (The
idea was that situations may come up where the assumptions of the atomic and
blocking APIs are not appropriate, so it should be possible for users to
handle these things in their own way.)
There are some limitations, which should not be too hard to live with. For
atomic/blocking chains, registration and unregistration must always be done in
a process context since the chain is protected by a mutex/rwsem. Also, a
callout routine for a non-raw chain must not try to register or unregister
entries on its own chain. (This did happen in a couple of places and the code
had to be changed to avoid it.)
Since atomic chains may be called from within an NMI handler, they cannot use
spinlocks for synchronization. Instead we use RCU. The overhead falls almost
entirely in the unregister routine, which is okay since unregistration is much
less frequent that calling a chain.
Here is the list of chains that we adjusted and their classifications. None
of them use the raw API, so for the moment it is only a placeholder.
ATOMIC CHAINS
-------------
arch/i386/kernel/traps.c: i386die_chain
arch/ia64/kernel/traps.c: ia64die_chain
arch/powerpc/kernel/traps.c: powerpc_die_chain
arch/sparc64/kernel/traps.c: sparc64die_chain
arch/x86_64/kernel/traps.c: die_chain
drivers/char/ipmi/ipmi_si_intf.c: xaction_notifier_list
kernel/panic.c: panic_notifier_list
kernel/profile.c: task_free_notifier
net/bluetooth/hci_core.c: hci_notifier
net/ipv4/netfilter/ip_conntrack_core.c: ip_conntrack_chain
net/ipv4/netfilter/ip_conntrack_core.c: ip_conntrack_expect_chain
net/ipv6/addrconf.c: inet6addr_chain
net/netfilter/nf_conntrack_core.c: nf_conntrack_chain
net/netfilter/nf_conntrack_core.c: nf_conntrack_expect_chain
net/netlink/af_netlink.c: netlink_chain
BLOCKING CHAINS
---------------
arch/powerpc/platforms/pseries/reconfig.c: pSeries_reconfig_chain
arch/s390/kernel/process.c: idle_chain
arch/x86_64/kernel/process.c idle_notifier
drivers/base/memory.c: memory_chain
drivers/cpufreq/cpufreq.c cpufreq_policy_notifier_list
drivers/cpufreq/cpufreq.c cpufreq_transition_notifier_list
drivers/macintosh/adb.c: adb_client_list
drivers/macintosh/via-pmu.c sleep_notifier_list
drivers/macintosh/via-pmu68k.c sleep_notifier_list
drivers/macintosh/windfarm_core.c wf_client_list
drivers/usb/core/notify.c usb_notifier_list
drivers/video/fbmem.c fb_notifier_list
kernel/cpu.c cpu_chain
kernel/module.c module_notify_list
kernel/profile.c munmap_notifier
kernel/profile.c task_exit_notifier
kernel/sys.c reboot_notifier_list
net/core/dev.c netdev_chain
net/decnet/dn_dev.c: dnaddr_chain
net/ipv4/devinet.c: inetaddr_chain
It's possible that some of these classifications are wrong. If they are,
please let us know or submit a patch to fix them. Note that any chain that
gets called very frequently should be atomic, because the rwsem read-locking
used for blocking chains is very likely to incur cache misses on SMP systems.
(However, if the chain's callout routines may sleep then the chain cannot be
atomic.)
The patch set was written by Alan Stern and Chandra Seetharaman, incorporating
material written by Keith Owens and suggestions from Paul McKenney and Andrew
Morton.
[jes@sgi.com: restructure the notifier chain initialization macros]
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Chandra Seetharaman <sekharan@us.ibm.com>
Signed-off-by: Jes Sorensen <jes@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-03-27 17:16:30 +08:00
|
|
|
&cpufreq_transition_notifier_list, nb);
|
2005-04-17 06:20:36 +08:00
|
|
|
break;
|
|
|
|
case CPUFREQ_POLICY_NOTIFIER:
|
[PATCH] Notifier chain update: API changes
The kernel's implementation of notifier chains is unsafe. There is no
protection against entries being added to or removed from a chain while the
chain is in use. The issues were discussed in this thread:
http://marc.theaimsgroup.com/?l=linux-kernel&m=113018709002036&w=2
We noticed that notifier chains in the kernel fall into two basic usage
classes:
"Blocking" chains are always called from a process context
and the callout routines are allowed to sleep;
"Atomic" chains can be called from an atomic context and
the callout routines are not allowed to sleep.
We decided to codify this distinction and make it part of the API. Therefore
this set of patches introduces three new, parallel APIs: one for blocking
notifiers, one for atomic notifiers, and one for "raw" notifiers (which is
really just the old API under a new name). New kinds of data structures are
used for the heads of the chains, and new routines are defined for
registration, unregistration, and calling a chain. The three APIs are
explained in include/linux/notifier.h and their implementation is in
kernel/sys.c.
With atomic and blocking chains, the implementation guarantees that the chain
links will not be corrupted and that chain callers will not get messed up by
entries being added or removed. For raw chains the implementation provides no
guarantees at all; users of this API must provide their own protections. (The
idea was that situations may come up where the assumptions of the atomic and
blocking APIs are not appropriate, so it should be possible for users to
handle these things in their own way.)
There are some limitations, which should not be too hard to live with. For
atomic/blocking chains, registration and unregistration must always be done in
a process context since the chain is protected by a mutex/rwsem. Also, a
callout routine for a non-raw chain must not try to register or unregister
entries on its own chain. (This did happen in a couple of places and the code
had to be changed to avoid it.)
Since atomic chains may be called from within an NMI handler, they cannot use
spinlocks for synchronization. Instead we use RCU. The overhead falls almost
entirely in the unregister routine, which is okay since unregistration is much
less frequent that calling a chain.
Here is the list of chains that we adjusted and their classifications. None
of them use the raw API, so for the moment it is only a placeholder.
ATOMIC CHAINS
-------------
arch/i386/kernel/traps.c: i386die_chain
arch/ia64/kernel/traps.c: ia64die_chain
arch/powerpc/kernel/traps.c: powerpc_die_chain
arch/sparc64/kernel/traps.c: sparc64die_chain
arch/x86_64/kernel/traps.c: die_chain
drivers/char/ipmi/ipmi_si_intf.c: xaction_notifier_list
kernel/panic.c: panic_notifier_list
kernel/profile.c: task_free_notifier
net/bluetooth/hci_core.c: hci_notifier
net/ipv4/netfilter/ip_conntrack_core.c: ip_conntrack_chain
net/ipv4/netfilter/ip_conntrack_core.c: ip_conntrack_expect_chain
net/ipv6/addrconf.c: inet6addr_chain
net/netfilter/nf_conntrack_core.c: nf_conntrack_chain
net/netfilter/nf_conntrack_core.c: nf_conntrack_expect_chain
net/netlink/af_netlink.c: netlink_chain
BLOCKING CHAINS
---------------
arch/powerpc/platforms/pseries/reconfig.c: pSeries_reconfig_chain
arch/s390/kernel/process.c: idle_chain
arch/x86_64/kernel/process.c idle_notifier
drivers/base/memory.c: memory_chain
drivers/cpufreq/cpufreq.c cpufreq_policy_notifier_list
drivers/cpufreq/cpufreq.c cpufreq_transition_notifier_list
drivers/macintosh/adb.c: adb_client_list
drivers/macintosh/via-pmu.c sleep_notifier_list
drivers/macintosh/via-pmu68k.c sleep_notifier_list
drivers/macintosh/windfarm_core.c wf_client_list
drivers/usb/core/notify.c usb_notifier_list
drivers/video/fbmem.c fb_notifier_list
kernel/cpu.c cpu_chain
kernel/module.c module_notify_list
kernel/profile.c munmap_notifier
kernel/profile.c task_exit_notifier
kernel/sys.c reboot_notifier_list
net/core/dev.c netdev_chain
net/decnet/dn_dev.c: dnaddr_chain
net/ipv4/devinet.c: inetaddr_chain
It's possible that some of these classifications are wrong. If they are,
please let us know or submit a patch to fix them. Note that any chain that
gets called very frequently should be atomic, because the rwsem read-locking
used for blocking chains is very likely to incur cache misses on SMP systems.
(However, if the chain's callout routines may sleep then the chain cannot be
atomic.)
The patch set was written by Alan Stern and Chandra Seetharaman, incorporating
material written by Keith Owens and suggestions from Paul McKenney and Andrew
Morton.
[jes@sgi.com: restructure the notifier chain initialization macros]
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Chandra Seetharaman <sekharan@us.ibm.com>
Signed-off-by: Jes Sorensen <jes@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-03-27 17:16:30 +08:00
|
|
|
ret = blocking_notifier_chain_unregister(
|
|
|
|
&cpufreq_policy_notifier_list, nb);
|
2005-04-17 06:20:36 +08:00
|
|
|
break;
|
|
|
|
default:
|
|
|
|
ret = -EINVAL;
|
|
|
|
}
|
|
|
|
|
|
|
|
return ret;
|
|
|
|
}
|
|
|
|
EXPORT_SYMBOL(cpufreq_unregister_notifier);
|
|
|
|
|
|
|
|
|
|
|
|
/*********************************************************************
|
|
|
|
* GOVERNORS *
|
|
|
|
*********************************************************************/
|
|
|
|
|
|
|
|
int __cpufreq_driver_target(struct cpufreq_policy *policy,
|
|
|
|
unsigned int target_freq,
|
|
|
|
unsigned int relation)
|
|
|
|
{
|
|
|
|
int retval = -EINVAL;
|
2012-10-31 08:28:21 +08:00
|
|
|
unsigned int old_target_freq = target_freq;
|
2005-10-31 06:59:54 +08:00
|
|
|
|
2012-03-14 07:18:39 +08:00
|
|
|
if (cpufreq_disabled())
|
|
|
|
return -ENODEV;
|
2013-06-19 12:46:55 +08:00
|
|
|
if (policy->transition_ongoing)
|
|
|
|
return -EBUSY;
|
2012-03-14 07:18:39 +08:00
|
|
|
|
2012-10-31 08:28:21 +08:00
|
|
|
/* Make sure that target_freq is within supported range */
|
|
|
|
if (target_freq > policy->max)
|
|
|
|
target_freq = policy->max;
|
|
|
|
if (target_freq < policy->min)
|
|
|
|
target_freq = policy->min;
|
|
|
|
|
|
|
|
pr_debug("target for CPU %u: %u kHz, relation %u, requested %u kHz\n",
|
|
|
|
policy->cpu, target_freq, relation, old_target_freq);
|
2012-10-31 08:28:15 +08:00
|
|
|
|
|
|
|
if (target_freq == policy->cur)
|
|
|
|
return 0;
|
|
|
|
|
2013-04-29 06:08:16 +08:00
|
|
|
if (cpufreq_driver->target)
|
|
|
|
retval = cpufreq_driver->target(policy, target_freq, relation);
|
2005-11-09 13:34:24 +08:00
|
|
|
|
2005-04-17 06:20:36 +08:00
|
|
|
return retval;
|
|
|
|
}
|
|
|
|
EXPORT_SYMBOL_GPL(__cpufreq_driver_target);
|
|
|
|
|
|
|
|
int cpufreq_driver_target(struct cpufreq_policy *policy,
|
|
|
|
unsigned int target_freq,
|
|
|
|
unsigned int relation)
|
|
|
|
{
|
2008-07-26 04:44:53 +08:00
|
|
|
int ret = -EINVAL;
|
2005-04-17 06:20:36 +08:00
|
|
|
|
2007-02-06 08:12:44 +08:00
|
|
|
if (unlikely(lock_policy_rwsem_write(policy->cpu)))
|
2008-07-26 04:44:53 +08:00
|
|
|
goto fail;
|
2005-04-17 06:20:36 +08:00
|
|
|
|
|
|
|
ret = __cpufreq_driver_target(policy, target_freq, relation);
|
|
|
|
|
2007-02-06 08:12:44 +08:00
|
|
|
unlock_policy_rwsem_write(policy->cpu);
|
2005-04-17 06:20:36 +08:00
|
|
|
|
2008-07-26 04:44:53 +08:00
|
|
|
fail:
|
2005-04-17 06:20:36 +08:00
|
|
|
return ret;
|
|
|
|
}
|
|
|
|
EXPORT_SYMBOL_GPL(cpufreq_driver_target);
|
|
|
|
|
2006-07-26 21:40:07 +08:00
|
|
|
/*
|
|
|
|
* when "event" is CPUFREQ_GOV_LIMITS
|
|
|
|
*/
|
2005-04-17 06:20:36 +08:00
|
|
|
|
2006-10-26 18:50:58 +08:00
|
|
|
static int __cpufreq_governor(struct cpufreq_policy *policy,
|
|
|
|
unsigned int event)
|
2005-04-17 06:20:36 +08:00
|
|
|
{
|
2005-07-29 00:43:56 +08:00
|
|
|
int ret;
|
2007-10-03 04:28:13 +08:00
|
|
|
|
|
|
|
/* Only must be defined when default governor is known to have latency
|
|
|
|
restrictions, like e.g. conservative or ondemand.
|
|
|
|
That this is the case is already ensured in Kconfig
|
|
|
|
*/
|
|
|
|
#ifdef CONFIG_CPU_FREQ_GOV_PERFORMANCE
|
|
|
|
struct cpufreq_governor *gov = &cpufreq_gov_performance;
|
|
|
|
#else
|
|
|
|
struct cpufreq_governor *gov = NULL;
|
|
|
|
#endif
|
2007-10-03 04:28:12 +08:00
|
|
|
|
|
|
|
if (policy->governor->max_transition_latency &&
|
|
|
|
policy->cpuinfo.transition_latency >
|
|
|
|
policy->governor->max_transition_latency) {
|
2007-10-03 04:28:13 +08:00
|
|
|
if (!gov)
|
|
|
|
return -EINVAL;
|
|
|
|
else {
|
|
|
|
printk(KERN_WARNING "%s governor failed, too long"
|
|
|
|
" transition latency of HW, fallback"
|
|
|
|
" to %s governor\n",
|
|
|
|
policy->governor->name,
|
|
|
|
gov->name);
|
|
|
|
policy->governor = gov;
|
|
|
|
}
|
2007-10-03 04:28:12 +08:00
|
|
|
}
|
2005-04-17 06:20:36 +08:00
|
|
|
|
|
|
|
if (!try_module_get(policy->governor->owner))
|
|
|
|
return -EINVAL;
|
|
|
|
|
2011-03-27 21:04:46 +08:00
|
|
|
pr_debug("__cpufreq_governor for CPU %u, event %u\n",
|
2006-10-26 18:50:58 +08:00
|
|
|
policy->cpu, event);
|
cpufreq: Fix governor start/stop race condition
Cpufreq governors' stop and start operations should be carried out
in sequence. Otherwise, there will be unexpected behavior, like in
the example below.
Suppose there are 4 CPUs and policy->cpu=CPU0, CPU1/2/3 are linked
to CPU0. The normal sequence is:
1) Current governor is userspace. An application tries to set the
governor to ondemand. It will call __cpufreq_set_policy() in
which it will stop the userspace governor and then start the
ondemand governor.
2) Current governor is userspace. The online of CPU3 runs on CPU0.
It will call cpufreq_add_policy_cpu() in which it will first
stop the userspace governor, and then start it again.
If the sequence of the above two cases interleaves, it becomes:
1) Application stops userspace governor
2) Hotplug stops userspace governor
which is a problem, because the governor shouldn't be stopped twice
in a row. What happens next is:
3) Application starts ondemand governor
4) Hotplug starts a governor
In step 4, the hotplug is supposed to start the userspace governor,
but now the governor has been changed by the application to ondemand,
so the ondemand governor is started once again, which is incorrect.
The solution is to prevent policy governors from being stopped
multiple times in a row. A governor should only be stopped once for
one policy. After it has been stopped, no more governor stop
operations should be executed.
Also add a mutex to serialize governor operations.
[rjw: Changelog. And you owe me a beverage of my choice.]
Signed-off-by: Xiaoguang Chen <chenxg@marvell.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2013-06-19 15:00:07 +08:00
|
|
|
|
|
|
|
mutex_lock(&cpufreq_governor_lock);
|
|
|
|
if ((!policy->governor_enabled && (event == CPUFREQ_GOV_STOP)) ||
|
|
|
|
(policy->governor_enabled && (event == CPUFREQ_GOV_START))) {
|
|
|
|
mutex_unlock(&cpufreq_governor_lock);
|
|
|
|
return -EBUSY;
|
|
|
|
}
|
|
|
|
|
|
|
|
if (event == CPUFREQ_GOV_STOP)
|
|
|
|
policy->governor_enabled = false;
|
|
|
|
else if (event == CPUFREQ_GOV_START)
|
|
|
|
policy->governor_enabled = true;
|
|
|
|
|
|
|
|
mutex_unlock(&cpufreq_governor_lock);
|
|
|
|
|
2005-04-17 06:20:36 +08:00
|
|
|
ret = policy->governor->governor(policy, event);
|
|
|
|
|
2013-03-27 23:58:58 +08:00
|
|
|
if (!ret) {
|
|
|
|
if (event == CPUFREQ_GOV_POLICY_INIT)
|
|
|
|
policy->governor->initialized++;
|
|
|
|
else if (event == CPUFREQ_GOV_POLICY_EXIT)
|
|
|
|
policy->governor->initialized--;
|
cpufreq: Fix governor start/stop race condition
Cpufreq governors' stop and start operations should be carried out
in sequence. Otherwise, there will be unexpected behavior, like in
the example below.
Suppose there are 4 CPUs and policy->cpu=CPU0, CPU1/2/3 are linked
to CPU0. The normal sequence is:
1) Current governor is userspace. An application tries to set the
governor to ondemand. It will call __cpufreq_set_policy() in
which it will stop the userspace governor and then start the
ondemand governor.
2) Current governor is userspace. The online of CPU3 runs on CPU0.
It will call cpufreq_add_policy_cpu() in which it will first
stop the userspace governor, and then start it again.
If the sequence of the above two cases interleaves, it becomes:
1) Application stops userspace governor
2) Hotplug stops userspace governor
which is a problem, because the governor shouldn't be stopped twice
in a row. What happens next is:
3) Application starts ondemand governor
4) Hotplug starts a governor
In step 4, the hotplug is supposed to start the userspace governor,
but now the governor has been changed by the application to ondemand,
so the ondemand governor is started once again, which is incorrect.
The solution is to prevent policy governors from being stopped
multiple times in a row. A governor should only be stopped once for
one policy. After it has been stopped, no more governor stop
operations should be executed.
Also add a mutex to serialize governor operations.
[rjw: Changelog. And you owe me a beverage of my choice.]
Signed-off-by: Xiaoguang Chen <chenxg@marvell.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2013-06-19 15:00:07 +08:00
|
|
|
} else {
|
|
|
|
/* Restore original values */
|
|
|
|
mutex_lock(&cpufreq_governor_lock);
|
|
|
|
if (event == CPUFREQ_GOV_STOP)
|
|
|
|
policy->governor_enabled = true;
|
|
|
|
else if (event == CPUFREQ_GOV_START)
|
|
|
|
policy->governor_enabled = false;
|
|
|
|
mutex_unlock(&cpufreq_governor_lock);
|
2013-03-27 23:58:58 +08:00
|
|
|
}
|
2013-02-01 13:42:58 +08:00
|
|
|
|
2006-10-26 18:50:58 +08:00
|
|
|
/* we keep one module reference alive for
|
|
|
|
each CPU governed by this CPU */
|
2005-04-17 06:20:36 +08:00
|
|
|
if ((event != CPUFREQ_GOV_START) || ret)
|
|
|
|
module_put(policy->governor->owner);
|
|
|
|
if ((event == CPUFREQ_GOV_STOP) && !ret)
|
|
|
|
module_put(policy->governor->owner);
|
|
|
|
|
|
|
|
return ret;
|
|
|
|
}
|
|
|
|
|
|
|
|
int cpufreq_register_governor(struct cpufreq_governor *governor)
|
|
|
|
{
|
2006-07-07 03:30:26 +08:00
|
|
|
int err;
|
2005-04-17 06:20:36 +08:00
|
|
|
|
|
|
|
if (!governor)
|
|
|
|
return -EINVAL;
|
|
|
|
|
2012-03-14 07:18:39 +08:00
|
|
|
if (cpufreq_disabled())
|
|
|
|
return -ENODEV;
|
|
|
|
|
2006-01-14 07:54:22 +08:00
|
|
|
mutex_lock(&cpufreq_governor_mutex);
|
2006-02-28 13:43:23 +08:00
|
|
|
|
2013-02-01 13:42:58 +08:00
|
|
|
governor->initialized = 0;
|
2006-07-07 03:30:26 +08:00
|
|
|
err = -EBUSY;
|
|
|
|
if (__find_governor(governor->name) == NULL) {
|
|
|
|
err = 0;
|
|
|
|
list_add(&governor->governor_list, &cpufreq_governor_list);
|
2005-04-17 06:20:36 +08:00
|
|
|
}
|
|
|
|
|
2006-02-28 13:43:23 +08:00
|
|
|
mutex_unlock(&cpufreq_governor_mutex);
|
2006-07-07 03:30:26 +08:00
|
|
|
return err;
|
2005-04-17 06:20:36 +08:00
|
|
|
}
|
|
|
|
EXPORT_SYMBOL_GPL(cpufreq_register_governor);
|
|
|
|
|
|
|
|
void cpufreq_unregister_governor(struct cpufreq_governor *governor)
|
|
|
|
{
|
2009-11-12 22:18:46 +08:00
|
|
|
#ifdef CONFIG_HOTPLUG_CPU
|
|
|
|
int cpu;
|
|
|
|
#endif
|
|
|
|
|
2005-04-17 06:20:36 +08:00
|
|
|
if (!governor)
|
|
|
|
return;
|
|
|
|
|
2012-03-14 07:18:39 +08:00
|
|
|
if (cpufreq_disabled())
|
|
|
|
return;
|
|
|
|
|
2009-11-12 22:18:46 +08:00
|
|
|
#ifdef CONFIG_HOTPLUG_CPU
|
|
|
|
for_each_present_cpu(cpu) {
|
|
|
|
if (cpu_online(cpu))
|
|
|
|
continue;
|
|
|
|
if (!strcmp(per_cpu(cpufreq_cpu_governor, cpu), governor->name))
|
|
|
|
strcpy(per_cpu(cpufreq_cpu_governor, cpu), "\0");
|
|
|
|
}
|
|
|
|
#endif
|
|
|
|
|
2006-01-14 07:54:22 +08:00
|
|
|
mutex_lock(&cpufreq_governor_mutex);
|
2005-04-17 06:20:36 +08:00
|
|
|
list_del(&governor->governor_list);
|
2006-01-14 07:54:22 +08:00
|
|
|
mutex_unlock(&cpufreq_governor_mutex);
|
2005-04-17 06:20:36 +08:00
|
|
|
return;
|
|
|
|
}
|
|
|
|
EXPORT_SYMBOL_GPL(cpufreq_unregister_governor);
|
|
|
|
|
|
|
|
|
|
|
|
/*********************************************************************
|
|
|
|
* POLICY INTERFACE *
|
|
|
|
*********************************************************************/
|
|
|
|
|
|
|
|
/**
|
|
|
|
* cpufreq_get_policy - get the current cpufreq_policy
|
2009-01-18 14:37:11 +08:00
|
|
|
* @policy: struct cpufreq_policy into which the current cpufreq_policy
|
|
|
|
* is written
|
2005-04-17 06:20:36 +08:00
|
|
|
*
|
|
|
|
* Reads the current cpufreq policy.
|
|
|
|
*/
|
|
|
|
int cpufreq_get_policy(struct cpufreq_policy *policy, unsigned int cpu)
|
|
|
|
{
|
|
|
|
struct cpufreq_policy *cpu_policy;
|
|
|
|
if (!policy)
|
|
|
|
return -EINVAL;
|
|
|
|
|
|
|
|
cpu_policy = cpufreq_cpu_get(cpu);
|
|
|
|
if (!cpu_policy)
|
|
|
|
return -EINVAL;
|
|
|
|
|
2013-08-07 01:23:06 +08:00
|
|
|
memcpy(policy, cpu_policy, sizeof(*policy));
|
2005-04-17 06:20:36 +08:00
|
|
|
|
|
|
|
cpufreq_cpu_put(cpu_policy);
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
EXPORT_SYMBOL(cpufreq_get_policy);
|
|
|
|
|
2006-07-26 21:40:07 +08:00
|
|
|
/*
|
2006-10-26 18:50:58 +08:00
|
|
|
* data : current policy.
|
|
|
|
* policy : policy to be set.
|
2006-07-26 21:40:07 +08:00
|
|
|
*/
|
2013-08-07 01:23:05 +08:00
|
|
|
static int __cpufreq_set_policy(struct cpufreq_policy *policy,
|
|
|
|
struct cpufreq_policy *new_policy)
|
2005-04-17 06:20:36 +08:00
|
|
|
{
|
2013-03-27 23:58:57 +08:00
|
|
|
int ret = 0, failed = 1;
|
2005-04-17 06:20:36 +08:00
|
|
|
|
2013-08-07 01:23:05 +08:00
|
|
|
pr_debug("setting new policy for CPU %u: %u - %u kHz\n", new_policy->cpu,
|
|
|
|
new_policy->min, new_policy->max);
|
2005-04-17 06:20:36 +08:00
|
|
|
|
2013-08-07 01:23:06 +08:00
|
|
|
memcpy(&new_policy->cpuinfo, &policy->cpuinfo, sizeof(policy->cpuinfo));
|
2005-04-17 06:20:36 +08:00
|
|
|
|
2013-08-07 01:23:05 +08:00
|
|
|
if (new_policy->min > policy->max || new_policy->max < policy->min) {
|
2006-07-06 05:12:20 +08:00
|
|
|
ret = -EINVAL;
|
|
|
|
goto error_out;
|
|
|
|
}
|
|
|
|
|
2005-04-17 06:20:36 +08:00
|
|
|
/* verify the cpu speed can be set within this limit */
|
2013-08-07 01:23:05 +08:00
|
|
|
ret = cpufreq_driver->verify(new_policy);
|
2005-04-17 06:20:36 +08:00
|
|
|
if (ret)
|
|
|
|
goto error_out;
|
|
|
|
|
|
|
|
/* adjust if necessary - all reasons */
|
[PATCH] Notifier chain update: API changes
The kernel's implementation of notifier chains is unsafe. There is no
protection against entries being added to or removed from a chain while the
chain is in use. The issues were discussed in this thread:
http://marc.theaimsgroup.com/?l=linux-kernel&m=113018709002036&w=2
We noticed that notifier chains in the kernel fall into two basic usage
classes:
"Blocking" chains are always called from a process context
and the callout routines are allowed to sleep;
"Atomic" chains can be called from an atomic context and
the callout routines are not allowed to sleep.
We decided to codify this distinction and make it part of the API. Therefore
this set of patches introduces three new, parallel APIs: one for blocking
notifiers, one for atomic notifiers, and one for "raw" notifiers (which is
really just the old API under a new name). New kinds of data structures are
used for the heads of the chains, and new routines are defined for
registration, unregistration, and calling a chain. The three APIs are
explained in include/linux/notifier.h and their implementation is in
kernel/sys.c.
With atomic and blocking chains, the implementation guarantees that the chain
links will not be corrupted and that chain callers will not get messed up by
entries being added or removed. For raw chains the implementation provides no
guarantees at all; users of this API must provide their own protections. (The
idea was that situations may come up where the assumptions of the atomic and
blocking APIs are not appropriate, so it should be possible for users to
handle these things in their own way.)
There are some limitations, which should not be too hard to live with. For
atomic/blocking chains, registration and unregistration must always be done in
a process context since the chain is protected by a mutex/rwsem. Also, a
callout routine for a non-raw chain must not try to register or unregister
entries on its own chain. (This did happen in a couple of places and the code
had to be changed to avoid it.)
Since atomic chains may be called from within an NMI handler, they cannot use
spinlocks for synchronization. Instead we use RCU. The overhead falls almost
entirely in the unregister routine, which is okay since unregistration is much
less frequent that calling a chain.
Here is the list of chains that we adjusted and their classifications. None
of them use the raw API, so for the moment it is only a placeholder.
ATOMIC CHAINS
-------------
arch/i386/kernel/traps.c: i386die_chain
arch/ia64/kernel/traps.c: ia64die_chain
arch/powerpc/kernel/traps.c: powerpc_die_chain
arch/sparc64/kernel/traps.c: sparc64die_chain
arch/x86_64/kernel/traps.c: die_chain
drivers/char/ipmi/ipmi_si_intf.c: xaction_notifier_list
kernel/panic.c: panic_notifier_list
kernel/profile.c: task_free_notifier
net/bluetooth/hci_core.c: hci_notifier
net/ipv4/netfilter/ip_conntrack_core.c: ip_conntrack_chain
net/ipv4/netfilter/ip_conntrack_core.c: ip_conntrack_expect_chain
net/ipv6/addrconf.c: inet6addr_chain
net/netfilter/nf_conntrack_core.c: nf_conntrack_chain
net/netfilter/nf_conntrack_core.c: nf_conntrack_expect_chain
net/netlink/af_netlink.c: netlink_chain
BLOCKING CHAINS
---------------
arch/powerpc/platforms/pseries/reconfig.c: pSeries_reconfig_chain
arch/s390/kernel/process.c: idle_chain
arch/x86_64/kernel/process.c idle_notifier
drivers/base/memory.c: memory_chain
drivers/cpufreq/cpufreq.c cpufreq_policy_notifier_list
drivers/cpufreq/cpufreq.c cpufreq_transition_notifier_list
drivers/macintosh/adb.c: adb_client_list
drivers/macintosh/via-pmu.c sleep_notifier_list
drivers/macintosh/via-pmu68k.c sleep_notifier_list
drivers/macintosh/windfarm_core.c wf_client_list
drivers/usb/core/notify.c usb_notifier_list
drivers/video/fbmem.c fb_notifier_list
kernel/cpu.c cpu_chain
kernel/module.c module_notify_list
kernel/profile.c munmap_notifier
kernel/profile.c task_exit_notifier
kernel/sys.c reboot_notifier_list
net/core/dev.c netdev_chain
net/decnet/dn_dev.c: dnaddr_chain
net/ipv4/devinet.c: inetaddr_chain
It's possible that some of these classifications are wrong. If they are,
please let us know or submit a patch to fix them. Note that any chain that
gets called very frequently should be atomic, because the rwsem read-locking
used for blocking chains is very likely to incur cache misses on SMP systems.
(However, if the chain's callout routines may sleep then the chain cannot be
atomic.)
The patch set was written by Alan Stern and Chandra Seetharaman, incorporating
material written by Keith Owens and suggestions from Paul McKenney and Andrew
Morton.
[jes@sgi.com: restructure the notifier chain initialization macros]
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Chandra Seetharaman <sekharan@us.ibm.com>
Signed-off-by: Jes Sorensen <jes@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-03-27 17:16:30 +08:00
|
|
|
blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
|
2013-08-07 01:23:05 +08:00
|
|
|
CPUFREQ_ADJUST, new_policy);
|
2005-04-17 06:20:36 +08:00
|
|
|
|
|
|
|
/* adjust if necessary - hardware incompatibility*/
|
[PATCH] Notifier chain update: API changes
The kernel's implementation of notifier chains is unsafe. There is no
protection against entries being added to or removed from a chain while the
chain is in use. The issues were discussed in this thread:
http://marc.theaimsgroup.com/?l=linux-kernel&m=113018709002036&w=2
We noticed that notifier chains in the kernel fall into two basic usage
classes:
"Blocking" chains are always called from a process context
and the callout routines are allowed to sleep;
"Atomic" chains can be called from an atomic context and
the callout routines are not allowed to sleep.
We decided to codify this distinction and make it part of the API. Therefore
this set of patches introduces three new, parallel APIs: one for blocking
notifiers, one for atomic notifiers, and one for "raw" notifiers (which is
really just the old API under a new name). New kinds of data structures are
used for the heads of the chains, and new routines are defined for
registration, unregistration, and calling a chain. The three APIs are
explained in include/linux/notifier.h and their implementation is in
kernel/sys.c.
With atomic and blocking chains, the implementation guarantees that the chain
links will not be corrupted and that chain callers will not get messed up by
entries being added or removed. For raw chains the implementation provides no
guarantees at all; users of this API must provide their own protections. (The
idea was that situations may come up where the assumptions of the atomic and
blocking APIs are not appropriate, so it should be possible for users to
handle these things in their own way.)
There are some limitations, which should not be too hard to live with. For
atomic/blocking chains, registration and unregistration must always be done in
a process context since the chain is protected by a mutex/rwsem. Also, a
callout routine for a non-raw chain must not try to register or unregister
entries on its own chain. (This did happen in a couple of places and the code
had to be changed to avoid it.)
Since atomic chains may be called from within an NMI handler, they cannot use
spinlocks for synchronization. Instead we use RCU. The overhead falls almost
entirely in the unregister routine, which is okay since unregistration is much
less frequent that calling a chain.
Here is the list of chains that we adjusted and their classifications. None
of them use the raw API, so for the moment it is only a placeholder.
ATOMIC CHAINS
-------------
arch/i386/kernel/traps.c: i386die_chain
arch/ia64/kernel/traps.c: ia64die_chain
arch/powerpc/kernel/traps.c: powerpc_die_chain
arch/sparc64/kernel/traps.c: sparc64die_chain
arch/x86_64/kernel/traps.c: die_chain
drivers/char/ipmi/ipmi_si_intf.c: xaction_notifier_list
kernel/panic.c: panic_notifier_list
kernel/profile.c: task_free_notifier
net/bluetooth/hci_core.c: hci_notifier
net/ipv4/netfilter/ip_conntrack_core.c: ip_conntrack_chain
net/ipv4/netfilter/ip_conntrack_core.c: ip_conntrack_expect_chain
net/ipv6/addrconf.c: inet6addr_chain
net/netfilter/nf_conntrack_core.c: nf_conntrack_chain
net/netfilter/nf_conntrack_core.c: nf_conntrack_expect_chain
net/netlink/af_netlink.c: netlink_chain
BLOCKING CHAINS
---------------
arch/powerpc/platforms/pseries/reconfig.c: pSeries_reconfig_chain
arch/s390/kernel/process.c: idle_chain
arch/x86_64/kernel/process.c idle_notifier
drivers/base/memory.c: memory_chain
drivers/cpufreq/cpufreq.c cpufreq_policy_notifier_list
drivers/cpufreq/cpufreq.c cpufreq_transition_notifier_list
drivers/macintosh/adb.c: adb_client_list
drivers/macintosh/via-pmu.c sleep_notifier_list
drivers/macintosh/via-pmu68k.c sleep_notifier_list
drivers/macintosh/windfarm_core.c wf_client_list
drivers/usb/core/notify.c usb_notifier_list
drivers/video/fbmem.c fb_notifier_list
kernel/cpu.c cpu_chain
kernel/module.c module_notify_list
kernel/profile.c munmap_notifier
kernel/profile.c task_exit_notifier
kernel/sys.c reboot_notifier_list
net/core/dev.c netdev_chain
net/decnet/dn_dev.c: dnaddr_chain
net/ipv4/devinet.c: inetaddr_chain
It's possible that some of these classifications are wrong. If they are,
please let us know or submit a patch to fix them. Note that any chain that
gets called very frequently should be atomic, because the rwsem read-locking
used for blocking chains is very likely to incur cache misses on SMP systems.
(However, if the chain's callout routines may sleep then the chain cannot be
atomic.)
The patch set was written by Alan Stern and Chandra Seetharaman, incorporating
material written by Keith Owens and suggestions from Paul McKenney and Andrew
Morton.
[jes@sgi.com: restructure the notifier chain initialization macros]
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Chandra Seetharaman <sekharan@us.ibm.com>
Signed-off-by: Jes Sorensen <jes@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-03-27 17:16:30 +08:00
|
|
|
blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
|
2013-08-07 01:23:05 +08:00
|
|
|
CPUFREQ_INCOMPATIBLE, new_policy);
|
2005-04-17 06:20:36 +08:00
|
|
|
|
2013-06-19 16:49:33 +08:00
|
|
|
/*
|
|
|
|
* verify the cpu speed can be set within this limit, which might be
|
|
|
|
* different to the first one
|
|
|
|
*/
|
2013-08-07 01:23:05 +08:00
|
|
|
ret = cpufreq_driver->verify(new_policy);
|
[PATCH] Notifier chain update: API changes
The kernel's implementation of notifier chains is unsafe. There is no
protection against entries being added to or removed from a chain while the
chain is in use. The issues were discussed in this thread:
http://marc.theaimsgroup.com/?l=linux-kernel&m=113018709002036&w=2
We noticed that notifier chains in the kernel fall into two basic usage
classes:
"Blocking" chains are always called from a process context
and the callout routines are allowed to sleep;
"Atomic" chains can be called from an atomic context and
the callout routines are not allowed to sleep.
We decided to codify this distinction and make it part of the API. Therefore
this set of patches introduces three new, parallel APIs: one for blocking
notifiers, one for atomic notifiers, and one for "raw" notifiers (which is
really just the old API under a new name). New kinds of data structures are
used for the heads of the chains, and new routines are defined for
registration, unregistration, and calling a chain. The three APIs are
explained in include/linux/notifier.h and their implementation is in
kernel/sys.c.
With atomic and blocking chains, the implementation guarantees that the chain
links will not be corrupted and that chain callers will not get messed up by
entries being added or removed. For raw chains the implementation provides no
guarantees at all; users of this API must provide their own protections. (The
idea was that situations may come up where the assumptions of the atomic and
blocking APIs are not appropriate, so it should be possible for users to
handle these things in their own way.)
There are some limitations, which should not be too hard to live with. For
atomic/blocking chains, registration and unregistration must always be done in
a process context since the chain is protected by a mutex/rwsem. Also, a
callout routine for a non-raw chain must not try to register or unregister
entries on its own chain. (This did happen in a couple of places and the code
had to be changed to avoid it.)
Since atomic chains may be called from within an NMI handler, they cannot use
spinlocks for synchronization. Instead we use RCU. The overhead falls almost
entirely in the unregister routine, which is okay since unregistration is much
less frequent that calling a chain.
Here is the list of chains that we adjusted and their classifications. None
of them use the raw API, so for the moment it is only a placeholder.
ATOMIC CHAINS
-------------
arch/i386/kernel/traps.c: i386die_chain
arch/ia64/kernel/traps.c: ia64die_chain
arch/powerpc/kernel/traps.c: powerpc_die_chain
arch/sparc64/kernel/traps.c: sparc64die_chain
arch/x86_64/kernel/traps.c: die_chain
drivers/char/ipmi/ipmi_si_intf.c: xaction_notifier_list
kernel/panic.c: panic_notifier_list
kernel/profile.c: task_free_notifier
net/bluetooth/hci_core.c: hci_notifier
net/ipv4/netfilter/ip_conntrack_core.c: ip_conntrack_chain
net/ipv4/netfilter/ip_conntrack_core.c: ip_conntrack_expect_chain
net/ipv6/addrconf.c: inet6addr_chain
net/netfilter/nf_conntrack_core.c: nf_conntrack_chain
net/netfilter/nf_conntrack_core.c: nf_conntrack_expect_chain
net/netlink/af_netlink.c: netlink_chain
BLOCKING CHAINS
---------------
arch/powerpc/platforms/pseries/reconfig.c: pSeries_reconfig_chain
arch/s390/kernel/process.c: idle_chain
arch/x86_64/kernel/process.c idle_notifier
drivers/base/memory.c: memory_chain
drivers/cpufreq/cpufreq.c cpufreq_policy_notifier_list
drivers/cpufreq/cpufreq.c cpufreq_transition_notifier_list
drivers/macintosh/adb.c: adb_client_list
drivers/macintosh/via-pmu.c sleep_notifier_list
drivers/macintosh/via-pmu68k.c sleep_notifier_list
drivers/macintosh/windfarm_core.c wf_client_list
drivers/usb/core/notify.c usb_notifier_list
drivers/video/fbmem.c fb_notifier_list
kernel/cpu.c cpu_chain
kernel/module.c module_notify_list
kernel/profile.c munmap_notifier
kernel/profile.c task_exit_notifier
kernel/sys.c reboot_notifier_list
net/core/dev.c netdev_chain
net/decnet/dn_dev.c: dnaddr_chain
net/ipv4/devinet.c: inetaddr_chain
It's possible that some of these classifications are wrong. If they are,
please let us know or submit a patch to fix them. Note that any chain that
gets called very frequently should be atomic, because the rwsem read-locking
used for blocking chains is very likely to incur cache misses on SMP systems.
(However, if the chain's callout routines may sleep then the chain cannot be
atomic.)
The patch set was written by Alan Stern and Chandra Seetharaman, incorporating
material written by Keith Owens and suggestions from Paul McKenney and Andrew
Morton.
[jes@sgi.com: restructure the notifier chain initialization macros]
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Chandra Seetharaman <sekharan@us.ibm.com>
Signed-off-by: Jes Sorensen <jes@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-03-27 17:16:30 +08:00
|
|
|
if (ret)
|
2005-04-17 06:20:36 +08:00
|
|
|
goto error_out;
|
|
|
|
|
|
|
|
/* notification of the new policy */
|
[PATCH] Notifier chain update: API changes
The kernel's implementation of notifier chains is unsafe. There is no
protection against entries being added to or removed from a chain while the
chain is in use. The issues were discussed in this thread:
http://marc.theaimsgroup.com/?l=linux-kernel&m=113018709002036&w=2
We noticed that notifier chains in the kernel fall into two basic usage
classes:
"Blocking" chains are always called from a process context
and the callout routines are allowed to sleep;
"Atomic" chains can be called from an atomic context and
the callout routines are not allowed to sleep.
We decided to codify this distinction and make it part of the API. Therefore
this set of patches introduces three new, parallel APIs: one for blocking
notifiers, one for atomic notifiers, and one for "raw" notifiers (which is
really just the old API under a new name). New kinds of data structures are
used for the heads of the chains, and new routines are defined for
registration, unregistration, and calling a chain. The three APIs are
explained in include/linux/notifier.h and their implementation is in
kernel/sys.c.
With atomic and blocking chains, the implementation guarantees that the chain
links will not be corrupted and that chain callers will not get messed up by
entries being added or removed. For raw chains the implementation provides no
guarantees at all; users of this API must provide their own protections. (The
idea was that situations may come up where the assumptions of the atomic and
blocking APIs are not appropriate, so it should be possible for users to
handle these things in their own way.)
There are some limitations, which should not be too hard to live with. For
atomic/blocking chains, registration and unregistration must always be done in
a process context since the chain is protected by a mutex/rwsem. Also, a
callout routine for a non-raw chain must not try to register or unregister
entries on its own chain. (This did happen in a couple of places and the code
had to be changed to avoid it.)
Since atomic chains may be called from within an NMI handler, they cannot use
spinlocks for synchronization. Instead we use RCU. The overhead falls almost
entirely in the unregister routine, which is okay since unregistration is much
less frequent that calling a chain.
Here is the list of chains that we adjusted and their classifications. None
of them use the raw API, so for the moment it is only a placeholder.
ATOMIC CHAINS
-------------
arch/i386/kernel/traps.c: i386die_chain
arch/ia64/kernel/traps.c: ia64die_chain
arch/powerpc/kernel/traps.c: powerpc_die_chain
arch/sparc64/kernel/traps.c: sparc64die_chain
arch/x86_64/kernel/traps.c: die_chain
drivers/char/ipmi/ipmi_si_intf.c: xaction_notifier_list
kernel/panic.c: panic_notifier_list
kernel/profile.c: task_free_notifier
net/bluetooth/hci_core.c: hci_notifier
net/ipv4/netfilter/ip_conntrack_core.c: ip_conntrack_chain
net/ipv4/netfilter/ip_conntrack_core.c: ip_conntrack_expect_chain
net/ipv6/addrconf.c: inet6addr_chain
net/netfilter/nf_conntrack_core.c: nf_conntrack_chain
net/netfilter/nf_conntrack_core.c: nf_conntrack_expect_chain
net/netlink/af_netlink.c: netlink_chain
BLOCKING CHAINS
---------------
arch/powerpc/platforms/pseries/reconfig.c: pSeries_reconfig_chain
arch/s390/kernel/process.c: idle_chain
arch/x86_64/kernel/process.c idle_notifier
drivers/base/memory.c: memory_chain
drivers/cpufreq/cpufreq.c cpufreq_policy_notifier_list
drivers/cpufreq/cpufreq.c cpufreq_transition_notifier_list
drivers/macintosh/adb.c: adb_client_list
drivers/macintosh/via-pmu.c sleep_notifier_list
drivers/macintosh/via-pmu68k.c sleep_notifier_list
drivers/macintosh/windfarm_core.c wf_client_list
drivers/usb/core/notify.c usb_notifier_list
drivers/video/fbmem.c fb_notifier_list
kernel/cpu.c cpu_chain
kernel/module.c module_notify_list
kernel/profile.c munmap_notifier
kernel/profile.c task_exit_notifier
kernel/sys.c reboot_notifier_list
net/core/dev.c netdev_chain
net/decnet/dn_dev.c: dnaddr_chain
net/ipv4/devinet.c: inetaddr_chain
It's possible that some of these classifications are wrong. If they are,
please let us know or submit a patch to fix them. Note that any chain that
gets called very frequently should be atomic, because the rwsem read-locking
used for blocking chains is very likely to incur cache misses on SMP systems.
(However, if the chain's callout routines may sleep then the chain cannot be
atomic.)
The patch set was written by Alan Stern and Chandra Seetharaman, incorporating
material written by Keith Owens and suggestions from Paul McKenney and Andrew
Morton.
[jes@sgi.com: restructure the notifier chain initialization macros]
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Chandra Seetharaman <sekharan@us.ibm.com>
Signed-off-by: Jes Sorensen <jes@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-03-27 17:16:30 +08:00
|
|
|
blocking_notifier_call_chain(&cpufreq_policy_notifier_list,
|
2013-08-07 01:23:05 +08:00
|
|
|
CPUFREQ_NOTIFY, new_policy);
|
2005-04-17 06:20:36 +08:00
|
|
|
|
2013-08-07 01:23:05 +08:00
|
|
|
policy->min = new_policy->min;
|
|
|
|
policy->max = new_policy->max;
|
2005-04-17 06:20:36 +08:00
|
|
|
|
2011-03-27 21:04:46 +08:00
|
|
|
pr_debug("new min and max freqs are %u - %u kHz\n",
|
2013-08-07 01:23:05 +08:00
|
|
|
policy->min, policy->max);
|
2005-04-17 06:20:36 +08:00
|
|
|
|
2013-04-29 06:08:16 +08:00
|
|
|
if (cpufreq_driver->setpolicy) {
|
2013-08-07 01:23:05 +08:00
|
|
|
policy->policy = new_policy->policy;
|
2011-03-27 21:04:46 +08:00
|
|
|
pr_debug("setting range\n");
|
2013-08-07 01:23:05 +08:00
|
|
|
ret = cpufreq_driver->setpolicy(new_policy);
|
2005-04-17 06:20:36 +08:00
|
|
|
} else {
|
2013-08-07 01:23:05 +08:00
|
|
|
if (new_policy->governor != policy->governor) {
|
2005-04-17 06:20:36 +08:00
|
|
|
/* save old, working values */
|
2013-08-07 01:23:05 +08:00
|
|
|
struct cpufreq_governor *old_gov = policy->governor;
|
2005-04-17 06:20:36 +08:00
|
|
|
|
2011-03-27 21:04:46 +08:00
|
|
|
pr_debug("governor switch\n");
|
2005-04-17 06:20:36 +08:00
|
|
|
|
|
|
|
/* end old governor */
|
2013-08-07 01:23:05 +08:00
|
|
|
if (policy->governor) {
|
|
|
|
__cpufreq_governor(policy, CPUFREQ_GOV_STOP);
|
|
|
|
unlock_policy_rwsem_write(new_policy->cpu);
|
|
|
|
__cpufreq_governor(policy,
|
2013-03-27 23:58:57 +08:00
|
|
|
CPUFREQ_GOV_POLICY_EXIT);
|
2013-08-07 01:23:05 +08:00
|
|
|
lock_policy_rwsem_write(new_policy->cpu);
|
2013-03-27 23:58:57 +08:00
|
|
|
}
|
2005-04-17 06:20:36 +08:00
|
|
|
|
|
|
|
/* start new governor */
|
2013-08-07 01:23:05 +08:00
|
|
|
policy->governor = new_policy->governor;
|
|
|
|
if (!__cpufreq_governor(policy, CPUFREQ_GOV_POLICY_INIT)) {
|
|
|
|
if (!__cpufreq_governor(policy, CPUFREQ_GOV_START)) {
|
2013-03-27 23:58:57 +08:00
|
|
|
failed = 0;
|
cpufreq: Drop rwsem lock around CPUFREQ_GOV_POLICY_EXIT
With the rwsem lock around
__cpufreq_governor(policy, CPUFREQ_GOV_POLICY_EXIT), we
get circular dependency when we call sysfs_remove_group().
======================================================
[ INFO: possible circular locking dependency detected ]
3.9.0-rc7+ #15 Not tainted
-------------------------------------------------------
cat/2387 is trying to acquire lock:
(&per_cpu(cpu_policy_rwsem, cpu)){+++++.}, at: [<c02f6179>] lock_policy_rwsem_read+0x25/0x34
but task is already holding lock:
(s_active#41){++++.+}, at: [<c00f9bf7>] sysfs_read_file+0x4f/0xcc
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #1 (s_active#41){++++.+}:
[<c0055a79>] lock_acquire+0x61/0xbc
[<c00fabf1>] sysfs_addrm_finish+0xc1/0x128
[<c00f9819>] sysfs_hash_and_remove+0x35/0x64
[<c00fbe6f>] remove_files.isra.0+0x1b/0x24
[<c00fbea5>] sysfs_remove_group+0x2d/0xa8
[<c02f9a0b>] cpufreq_governor_interactive+0x13b/0x35c
[<c02f61df>] __cpufreq_governor+0x2b/0x8c
[<c02f6579>] __cpufreq_set_policy+0xa9/0xf8
[<c02f6b75>] store_scaling_governor+0x61/0x100
[<c02f6f4d>] store+0x39/0x60
[<c00f9b81>] sysfs_write_file+0xed/0x114
[<c00b3fd1>] vfs_write+0x65/0xd8
[<c00b424b>] sys_write+0x2f/0x50
[<c000cdc1>] ret_fast_syscall+0x1/0x52
-> #0 (&per_cpu(cpu_policy_rwsem, cpu)){+++++.}:
[<c0055253>] __lock_acquire+0xef3/0x13dc
[<c0055a79>] lock_acquire+0x61/0xbc
[<c03ee1f5>] down_read+0x25/0x30
[<c02f6179>] lock_policy_rwsem_read+0x25/0x34
[<c02f6edd>] show+0x21/0x58
[<c00f9c0f>] sysfs_read_file+0x67/0xcc
[<c00b40a7>] vfs_read+0x63/0xd8
[<c00b41fb>] sys_read+0x2f/0x50
[<c000cdc1>] ret_fast_syscall+0x1/0x52
other info that might help us debug this:
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(s_active#41);
lock(&per_cpu(cpu_policy_rwsem, cpu));
lock(s_active#41);
lock(&per_cpu(cpu_policy_rwsem, cpu));
*** DEADLOCK ***
2 locks held by cat/2387:
#0: (&buffer->mutex){+.+.+.}, at: [<c00f9bcd>] sysfs_read_file+0x25/0xcc
#1: (s_active#41){++++.+}, at: [<c00f9bf7>] sysfs_read_file+0x4f/0xcc
stack backtrace:
[<c0011d55>] (unwind_backtrace+0x1/0x9c) from [<c03e9a09>] (print_circular_bug+0x19d/0x1e8)
[<c03e9a09>] (print_circular_bug+0x19d/0x1e8) from [<c0055253>] (__lock_acquire+0xef3/0x13dc)
[<c0055253>] (__lock_acquire+0xef3/0x13dc) from [<c0055a79>] (lock_acquire+0x61/0xbc)
[<c0055a79>] (lock_acquire+0x61/0xbc) from [<c03ee1f5>] (down_read+0x25/0x30)
[<c03ee1f5>] (down_read+0x25/0x30) from [<c02f6179>] (lock_policy_rwsem_read+0x25/0x34)
[<c02f6179>] (lock_policy_rwsem_read+0x25/0x34) from [<c02f6edd>] (show+0x21/0x58)
[<c02f6edd>] (show+0x21/0x58) from [<c00f9c0f>] (sysfs_read_file+0x67/0xcc)
[<c00f9c0f>] (sysfs_read_file+0x67/0xcc) from [<c00b40a7>] (vfs_read+0x63/0xd8)
[<c00b40a7>] (vfs_read+0x63/0xd8) from [<c00b41fb>] (sys_read+0x2f/0x50)
[<c00b41fb>] (sys_read+0x2f/0x50) from [<c000cdc1>] (ret_fast_syscall+0x1/0x52)
This lock isn't required while calling __cpufreq_governor(policy,
CPUFREQ_GOV_POLICY_EXIT). Remove it.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2013-05-16 13:09:58 +08:00
|
|
|
} else {
|
2013-08-07 01:23:05 +08:00
|
|
|
unlock_policy_rwsem_write(new_policy->cpu);
|
|
|
|
__cpufreq_governor(policy,
|
2013-03-27 23:58:57 +08:00
|
|
|
CPUFREQ_GOV_POLICY_EXIT);
|
2013-08-07 01:23:05 +08:00
|
|
|
lock_policy_rwsem_write(new_policy->cpu);
|
cpufreq: Drop rwsem lock around CPUFREQ_GOV_POLICY_EXIT
With the rwsem lock around
__cpufreq_governor(policy, CPUFREQ_GOV_POLICY_EXIT), we
get circular dependency when we call sysfs_remove_group().
======================================================
[ INFO: possible circular locking dependency detected ]
3.9.0-rc7+ #15 Not tainted
-------------------------------------------------------
cat/2387 is trying to acquire lock:
(&per_cpu(cpu_policy_rwsem, cpu)){+++++.}, at: [<c02f6179>] lock_policy_rwsem_read+0x25/0x34
but task is already holding lock:
(s_active#41){++++.+}, at: [<c00f9bf7>] sysfs_read_file+0x4f/0xcc
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #1 (s_active#41){++++.+}:
[<c0055a79>] lock_acquire+0x61/0xbc
[<c00fabf1>] sysfs_addrm_finish+0xc1/0x128
[<c00f9819>] sysfs_hash_and_remove+0x35/0x64
[<c00fbe6f>] remove_files.isra.0+0x1b/0x24
[<c00fbea5>] sysfs_remove_group+0x2d/0xa8
[<c02f9a0b>] cpufreq_governor_interactive+0x13b/0x35c
[<c02f61df>] __cpufreq_governor+0x2b/0x8c
[<c02f6579>] __cpufreq_set_policy+0xa9/0xf8
[<c02f6b75>] store_scaling_governor+0x61/0x100
[<c02f6f4d>] store+0x39/0x60
[<c00f9b81>] sysfs_write_file+0xed/0x114
[<c00b3fd1>] vfs_write+0x65/0xd8
[<c00b424b>] sys_write+0x2f/0x50
[<c000cdc1>] ret_fast_syscall+0x1/0x52
-> #0 (&per_cpu(cpu_policy_rwsem, cpu)){+++++.}:
[<c0055253>] __lock_acquire+0xef3/0x13dc
[<c0055a79>] lock_acquire+0x61/0xbc
[<c03ee1f5>] down_read+0x25/0x30
[<c02f6179>] lock_policy_rwsem_read+0x25/0x34
[<c02f6edd>] show+0x21/0x58
[<c00f9c0f>] sysfs_read_file+0x67/0xcc
[<c00b40a7>] vfs_read+0x63/0xd8
[<c00b41fb>] sys_read+0x2f/0x50
[<c000cdc1>] ret_fast_syscall+0x1/0x52
other info that might help us debug this:
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(s_active#41);
lock(&per_cpu(cpu_policy_rwsem, cpu));
lock(s_active#41);
lock(&per_cpu(cpu_policy_rwsem, cpu));
*** DEADLOCK ***
2 locks held by cat/2387:
#0: (&buffer->mutex){+.+.+.}, at: [<c00f9bcd>] sysfs_read_file+0x25/0xcc
#1: (s_active#41){++++.+}, at: [<c00f9bf7>] sysfs_read_file+0x4f/0xcc
stack backtrace:
[<c0011d55>] (unwind_backtrace+0x1/0x9c) from [<c03e9a09>] (print_circular_bug+0x19d/0x1e8)
[<c03e9a09>] (print_circular_bug+0x19d/0x1e8) from [<c0055253>] (__lock_acquire+0xef3/0x13dc)
[<c0055253>] (__lock_acquire+0xef3/0x13dc) from [<c0055a79>] (lock_acquire+0x61/0xbc)
[<c0055a79>] (lock_acquire+0x61/0xbc) from [<c03ee1f5>] (down_read+0x25/0x30)
[<c03ee1f5>] (down_read+0x25/0x30) from [<c02f6179>] (lock_policy_rwsem_read+0x25/0x34)
[<c02f6179>] (lock_policy_rwsem_read+0x25/0x34) from [<c02f6edd>] (show+0x21/0x58)
[<c02f6edd>] (show+0x21/0x58) from [<c00f9c0f>] (sysfs_read_file+0x67/0xcc)
[<c00f9c0f>] (sysfs_read_file+0x67/0xcc) from [<c00b40a7>] (vfs_read+0x63/0xd8)
[<c00b40a7>] (vfs_read+0x63/0xd8) from [<c00b41fb>] (sys_read+0x2f/0x50)
[<c00b41fb>] (sys_read+0x2f/0x50) from [<c000cdc1>] (ret_fast_syscall+0x1/0x52)
This lock isn't required while calling __cpufreq_governor(policy,
CPUFREQ_GOV_POLICY_EXIT). Remove it.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2013-05-16 13:09:58 +08:00
|
|
|
}
|
2013-03-27 23:58:57 +08:00
|
|
|
}
|
|
|
|
|
|
|
|
if (failed) {
|
2005-04-17 06:20:36 +08:00
|
|
|
/* new governor failed, so re-start old one */
|
2011-03-27 21:04:46 +08:00
|
|
|
pr_debug("starting governor %s failed\n",
|
2013-08-07 01:23:05 +08:00
|
|
|
policy->governor->name);
|
2005-04-17 06:20:36 +08:00
|
|
|
if (old_gov) {
|
2013-08-07 01:23:05 +08:00
|
|
|
policy->governor = old_gov;
|
|
|
|
__cpufreq_governor(policy,
|
2013-03-27 23:58:57 +08:00
|
|
|
CPUFREQ_GOV_POLICY_INIT);
|
2013-08-07 01:23:05 +08:00
|
|
|
__cpufreq_governor(policy,
|
2006-10-26 18:50:58 +08:00
|
|
|
CPUFREQ_GOV_START);
|
2005-04-17 06:20:36 +08:00
|
|
|
}
|
|
|
|
ret = -EINVAL;
|
|
|
|
goto error_out;
|
|
|
|
}
|
|
|
|
/* might be a policy change, too, so fall through */
|
|
|
|
}
|
2011-03-27 21:04:46 +08:00
|
|
|
pr_debug("governor: change or update limits\n");
|
2013-08-07 01:23:05 +08:00
|
|
|
__cpufreq_governor(policy, CPUFREQ_GOV_LIMITS);
|
2005-04-17 06:20:36 +08:00
|
|
|
}
|
|
|
|
|
2006-02-03 06:03:42 +08:00
|
|
|
error_out:
|
2005-04-17 06:20:36 +08:00
|
|
|
return ret;
|
|
|
|
}
|
|
|
|
|
|
|
|
/**
|
|
|
|
* cpufreq_update_policy - re-evaluate an existing cpufreq policy
|
|
|
|
* @cpu: CPU which shall be re-evaluated
|
|
|
|
*
|
2011-03-31 09:57:33 +08:00
|
|
|
* Useful for policy notifiers which have different necessities
|
2005-04-17 06:20:36 +08:00
|
|
|
* at different times.
|
|
|
|
*/
|
|
|
|
int cpufreq_update_policy(unsigned int cpu)
|
|
|
|
{
|
2013-08-07 01:23:05 +08:00
|
|
|
struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
|
|
|
|
struct cpufreq_policy new_policy;
|
2008-07-26 04:44:53 +08:00
|
|
|
int ret;
|
2005-04-17 06:20:36 +08:00
|
|
|
|
2013-08-07 01:23:05 +08:00
|
|
|
if (!policy) {
|
2008-07-26 04:44:53 +08:00
|
|
|
ret = -ENODEV;
|
|
|
|
goto no_policy;
|
|
|
|
}
|
2005-04-17 06:20:36 +08:00
|
|
|
|
2008-07-26 04:44:53 +08:00
|
|
|
if (unlikely(lock_policy_rwsem_write(cpu))) {
|
|
|
|
ret = -EINVAL;
|
|
|
|
goto fail;
|
|
|
|
}
|
2005-04-17 06:20:36 +08:00
|
|
|
|
2011-03-27 21:04:46 +08:00
|
|
|
pr_debug("updating policy for CPU %u\n", cpu);
|
2013-08-07 01:23:06 +08:00
|
|
|
memcpy(&new_policy, policy, sizeof(*policy));
|
2013-08-07 01:23:05 +08:00
|
|
|
new_policy.min = policy->user_policy.min;
|
|
|
|
new_policy.max = policy->user_policy.max;
|
|
|
|
new_policy.policy = policy->user_policy.policy;
|
|
|
|
new_policy.governor = policy->user_policy.governor;
|
2005-04-17 06:20:36 +08:00
|
|
|
|
2013-06-19 16:49:33 +08:00
|
|
|
/*
|
|
|
|
* BIOS might change freq behind our back
|
|
|
|
* -> ask driver for current freq and notify governors about a change
|
|
|
|
*/
|
2013-04-29 06:08:16 +08:00
|
|
|
if (cpufreq_driver->get) {
|
2013-08-07 01:23:05 +08:00
|
|
|
new_policy.cur = cpufreq_driver->get(cpu);
|
|
|
|
if (!policy->cur) {
|
2011-03-27 21:04:46 +08:00
|
|
|
pr_debug("Driver did not initialize current freq");
|
2013-08-07 01:23:05 +08:00
|
|
|
policy->cur = new_policy.cur;
|
2006-02-01 18:36:04 +08:00
|
|
|
} else {
|
2013-08-07 01:23:05 +08:00
|
|
|
if (policy->cur != new_policy.cur && cpufreq_driver->target)
|
|
|
|
cpufreq_out_of_sync(cpu, policy->cur,
|
|
|
|
new_policy.cur);
|
2006-02-01 18:36:04 +08:00
|
|
|
}
|
2006-01-27 01:46:33 +08:00
|
|
|
}
|
|
|
|
|
2013-08-07 01:23:05 +08:00
|
|
|
ret = __cpufreq_set_policy(policy, &new_policy);
|
2005-04-17 06:20:36 +08:00
|
|
|
|
2007-02-06 08:12:44 +08:00
|
|
|
unlock_policy_rwsem_write(cpu);
|
|
|
|
|
2008-07-26 04:44:53 +08:00
|
|
|
fail:
|
2013-08-07 01:23:05 +08:00
|
|
|
cpufreq_cpu_put(policy);
|
2008-07-26 04:44:53 +08:00
|
|
|
no_policy:
|
2005-04-17 06:20:36 +08:00
|
|
|
return ret;
|
|
|
|
}
|
|
|
|
EXPORT_SYMBOL(cpufreq_update_policy);
|
|
|
|
|
2013-06-20 01:54:04 +08:00
|
|
|
static int cpufreq_cpu_callback(struct notifier_block *nfb,
|
2005-10-31 06:59:54 +08:00
|
|
|
unsigned long action, void *hcpu)
|
|
|
|
{
|
|
|
|
unsigned int cpu = (unsigned long)hcpu;
|
2011-12-22 06:29:42 +08:00
|
|
|
struct device *dev;
|
2013-07-30 06:55:25 +08:00
|
|
|
bool frozen = false;
|
2005-10-31 06:59:54 +08:00
|
|
|
|
2011-12-22 06:29:42 +08:00
|
|
|
dev = get_cpu_device(cpu);
|
|
|
|
if (dev) {
|
2013-07-30 06:55:25 +08:00
|
|
|
|
|
|
|
if (action & CPU_TASKS_FROZEN)
|
|
|
|
frozen = true;
|
|
|
|
|
|
|
|
switch (action & ~CPU_TASKS_FROZEN) {
|
2005-10-31 06:59:54 +08:00
|
|
|
case CPU_ONLINE:
|
2013-07-30 06:55:25 +08:00
|
|
|
__cpufreq_add_dev(dev, NULL, frozen);
|
2013-07-30 06:53:56 +08:00
|
|
|
cpufreq_update_policy(cpu);
|
2005-10-31 06:59:54 +08:00
|
|
|
break;
|
2013-07-30 06:55:25 +08:00
|
|
|
|
2005-10-31 06:59:54 +08:00
|
|
|
case CPU_DOWN_PREPARE:
|
2013-07-30 06:55:25 +08:00
|
|
|
__cpufreq_remove_dev(dev, NULL, frozen);
|
2005-10-31 06:59:54 +08:00
|
|
|
break;
|
2013-07-30 06:55:25 +08:00
|
|
|
|
2007-02-06 08:12:44 +08:00
|
|
|
case CPU_DOWN_FAILED:
|
2013-07-30 06:55:25 +08:00
|
|
|
__cpufreq_add_dev(dev, NULL, frozen);
|
2005-10-31 06:59:54 +08:00
|
|
|
break;
|
|
|
|
}
|
|
|
|
}
|
|
|
|
return NOTIFY_OK;
|
|
|
|
}
|
|
|
|
|
2010-06-23 11:02:44 +08:00
|
|
|
static struct notifier_block __refdata cpufreq_cpu_notifier = {
|
2013-06-19 16:49:33 +08:00
|
|
|
.notifier_call = cpufreq_cpu_callback,
|
2005-10-31 06:59:54 +08:00
|
|
|
};
|
2005-04-17 06:20:36 +08:00
|
|
|
|
|
|
|
/*********************************************************************
|
|
|
|
* REGISTER / UNREGISTER CPUFREQ DRIVER *
|
|
|
|
*********************************************************************/
|
|
|
|
|
|
|
|
/**
|
|
|
|
* cpufreq_register_driver - register a CPU Frequency driver
|
|
|
|
* @driver_data: A struct cpufreq_driver containing the values#
|
|
|
|
* submitted by the CPU Frequency driver.
|
|
|
|
*
|
2013-06-19 16:49:33 +08:00
|
|
|
* Registers a CPU Frequency driver to this core code. This code
|
2005-04-17 06:20:36 +08:00
|
|
|
* returns zero on success, -EBUSY when another driver got here first
|
2006-02-28 13:43:23 +08:00
|
|
|
* (and isn't unregistered in the meantime).
|
2005-04-17 06:20:36 +08:00
|
|
|
*
|
|
|
|
*/
|
2007-02-27 06:55:48 +08:00
|
|
|
int cpufreq_register_driver(struct cpufreq_driver *driver_data)
|
2005-04-17 06:20:36 +08:00
|
|
|
{
|
|
|
|
unsigned long flags;
|
|
|
|
int ret;
|
|
|
|
|
2012-03-14 07:18:39 +08:00
|
|
|
if (cpufreq_disabled())
|
|
|
|
return -ENODEV;
|
|
|
|
|
2005-04-17 06:20:36 +08:00
|
|
|
if (!driver_data || !driver_data->verify || !driver_data->init ||
|
|
|
|
((!driver_data->setpolicy) && (!driver_data->target)))
|
|
|
|
return -EINVAL;
|
|
|
|
|
2011-03-27 21:04:46 +08:00
|
|
|
pr_debug("trying to register driver %s\n", driver_data->name);
|
2005-04-17 06:20:36 +08:00
|
|
|
|
|
|
|
if (driver_data->setpolicy)
|
|
|
|
driver_data->flags |= CPUFREQ_CONST_LOOPS;
|
|
|
|
|
2013-02-23 00:24:34 +08:00
|
|
|
write_lock_irqsave(&cpufreq_driver_lock, flags);
|
2013-04-29 06:08:16 +08:00
|
|
|
if (cpufreq_driver) {
|
2013-02-23 00:24:34 +08:00
|
|
|
write_unlock_irqrestore(&cpufreq_driver_lock, flags);
|
2005-04-17 06:20:36 +08:00
|
|
|
return -EBUSY;
|
|
|
|
}
|
2013-04-29 06:08:16 +08:00
|
|
|
cpufreq_driver = driver_data;
|
2013-02-23 00:24:34 +08:00
|
|
|
write_unlock_irqrestore(&cpufreq_driver_lock, flags);
|
2005-04-17 06:20:36 +08:00
|
|
|
|
2011-12-22 06:29:42 +08:00
|
|
|
ret = subsys_interface_register(&cpufreq_interface);
|
2011-03-02 00:41:10 +08:00
|
|
|
if (ret)
|
|
|
|
goto err_null_driver;
|
2005-04-17 06:20:36 +08:00
|
|
|
|
2013-04-29 06:08:16 +08:00
|
|
|
if (!(cpufreq_driver->flags & CPUFREQ_STICKY)) {
|
2005-04-17 06:20:36 +08:00
|
|
|
int i;
|
|
|
|
ret = -ENODEV;
|
|
|
|
|
|
|
|
/* check for at least one working CPU */
|
2008-03-26 06:06:53 +08:00
|
|
|
for (i = 0; i < nr_cpu_ids; i++)
|
|
|
|
if (cpu_possible(i) && per_cpu(cpufreq_cpu_data, i)) {
|
2005-04-17 06:20:36 +08:00
|
|
|
ret = 0;
|
2008-03-26 06:06:53 +08:00
|
|
|
break;
|
|
|
|
}
|
2005-04-17 06:20:36 +08:00
|
|
|
|
|
|
|
/* if all ->init() calls failed, unregister */
|
|
|
|
if (ret) {
|
2011-03-27 21:04:46 +08:00
|
|
|
pr_debug("no CPU initialized for driver %s\n",
|
2006-10-26 18:50:58 +08:00
|
|
|
driver_data->name);
|
2011-12-22 06:29:42 +08:00
|
|
|
goto err_if_unreg;
|
2005-04-17 06:20:36 +08:00
|
|
|
}
|
|
|
|
}
|
|
|
|
|
2011-03-02 00:41:10 +08:00
|
|
|
register_hotcpu_notifier(&cpufreq_cpu_notifier);
|
2011-03-27 21:04:46 +08:00
|
|
|
pr_debug("driver %s up and running\n", driver_data->name);
|
2005-04-17 06:20:36 +08:00
|
|
|
|
2011-03-02 00:41:10 +08:00
|
|
|
return 0;
|
2011-12-22 06:29:42 +08:00
|
|
|
err_if_unreg:
|
|
|
|
subsys_interface_unregister(&cpufreq_interface);
|
2011-03-02 00:41:10 +08:00
|
|
|
err_null_driver:
|
2013-02-23 00:24:34 +08:00
|
|
|
write_lock_irqsave(&cpufreq_driver_lock, flags);
|
2013-04-29 06:08:16 +08:00
|
|
|
cpufreq_driver = NULL;
|
2013-02-23 00:24:34 +08:00
|
|
|
write_unlock_irqrestore(&cpufreq_driver_lock, flags);
|
2008-02-08 05:33:49 +08:00
|
|
|
return ret;
|
2005-04-17 06:20:36 +08:00
|
|
|
}
|
|
|
|
EXPORT_SYMBOL_GPL(cpufreq_register_driver);
|
|
|
|
|
|
|
|
/**
|
|
|
|
* cpufreq_unregister_driver - unregister the current CPUFreq driver
|
|
|
|
*
|
2013-06-19 16:49:33 +08:00
|
|
|
* Unregister the current CPUFreq driver. Only call this if you have
|
2005-04-17 06:20:36 +08:00
|
|
|
* the right to do so, i.e. if you have succeeded in initialising before!
|
|
|
|
* Returns zero if successful, and -EINVAL if the cpufreq_driver is
|
|
|
|
* currently not initialised.
|
|
|
|
*/
|
2007-02-27 06:55:48 +08:00
|
|
|
int cpufreq_unregister_driver(struct cpufreq_driver *driver)
|
2005-04-17 06:20:36 +08:00
|
|
|
{
|
|
|
|
unsigned long flags;
|
|
|
|
|
2013-04-29 06:08:16 +08:00
|
|
|
if (!cpufreq_driver || (driver != cpufreq_driver))
|
2005-04-17 06:20:36 +08:00
|
|
|
return -EINVAL;
|
|
|
|
|
2011-03-27 21:04:46 +08:00
|
|
|
pr_debug("unregistering driver %s\n", driver->name);
|
2005-04-17 06:20:36 +08:00
|
|
|
|
2011-12-22 06:29:42 +08:00
|
|
|
subsys_interface_unregister(&cpufreq_interface);
|
2006-06-27 17:54:08 +08:00
|
|
|
unregister_hotcpu_notifier(&cpufreq_cpu_notifier);
|
2005-04-17 06:20:36 +08:00
|
|
|
|
2013-02-23 00:24:34 +08:00
|
|
|
write_lock_irqsave(&cpufreq_driver_lock, flags);
|
2013-04-29 06:08:16 +08:00
|
|
|
cpufreq_driver = NULL;
|
2013-02-23 00:24:34 +08:00
|
|
|
write_unlock_irqrestore(&cpufreq_driver_lock, flags);
|
2005-04-17 06:20:36 +08:00
|
|
|
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
EXPORT_SYMBOL_GPL(cpufreq_unregister_driver);
|
2007-02-06 08:12:44 +08:00
|
|
|
|
|
|
|
static int __init cpufreq_core_init(void)
|
|
|
|
{
|
|
|
|
int cpu;
|
|
|
|
|
2012-03-14 07:18:39 +08:00
|
|
|
if (cpufreq_disabled())
|
|
|
|
return -ENODEV;
|
|
|
|
|
2007-02-06 08:12:44 +08:00
|
|
|
for_each_possible_cpu(cpu) {
|
2009-10-29 21:34:13 +08:00
|
|
|
per_cpu(cpufreq_policy_cpu, cpu) = -1;
|
2007-02-06 08:12:44 +08:00
|
|
|
init_rwsem(&per_cpu(cpu_policy_rwsem, cpu));
|
|
|
|
}
|
2009-07-24 21:25:05 +08:00
|
|
|
|
2013-05-17 18:39:09 +08:00
|
|
|
cpufreq_global_kobject = kobject_create();
|
2009-07-24 21:25:05 +08:00
|
|
|
BUG_ON(!cpufreq_global_kobject);
|
cpufreq: Use syscore_ops for boot CPU suspend/resume (v2)
The cpufreq subsystem uses sysdev suspend and resume for
executing cpufreq_suspend() and cpufreq_resume(), respectively,
during system suspend, after interrupts have been switched off on the
boot CPU, and during system resume, while interrupts are still off on
the boot CPU. In both cases the other CPUs are off-line at the
relevant point (either they have been switched off via CPU hotplug
during suspend, or they haven't been switched on yet during resume).
For this reason, although it may seem that cpufreq_suspend() and
cpufreq_resume() are executed for all CPUs in the system, they are
only called for the boot CPU in fact, which is quite confusing.
To remove the confusion and to prepare for elimiating sysdev
suspend and resume operations from the kernel enirely, convernt
cpufreq to using a struct syscore_ops object for the boot CPU
suspend and resume and rename the callbacks so that their names
reflect their purpose. In addition, put some explanatory remarks
into their kerneldoc comments.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
2011-03-24 05:16:32 +08:00
|
|
|
register_syscore_ops(&cpufreq_syscore_ops);
|
2009-07-24 21:25:05 +08:00
|
|
|
|
2007-02-06 08:12:44 +08:00
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
core_initcall(cpufreq_core_init);
|