kernel_optimize_test/kernel
Jason Low 47667fa150 locking/mutexes: Modify the way optimistic spinners are queued
The mutex->spin_mlock was introduced in order to ensure that only 1 thread
spins for lock acquisition at a time to reduce cache line contention. When
lock->owner is NULL and the lock->count is still not 1, the spinner(s) will
continually release and obtain the lock->spin_mlock. This can generate
quite a bit of overhead/contention, and also might just delay the spinner
from getting the lock.

This patch modifies the way optimistic spinners are queued by queuing before
entering the optimistic spinning loop as oppose to acquiring before every
call to mutex_spin_on_owner(). So in situations where the spinner requires
a few extra spins before obtaining the lock, then there will only be 1 spinner
trying to get the lock and it will avoid the overhead from unnecessarily
unlocking and locking the spin_mlock.

Signed-off-by: Jason Low <jason.low2@hp.com>
Cc: tglx@linutronix.de
Cc: riel@redhat.com
Cc: akpm@linux-foundation.org
Cc: davidlohr@hp.com
Cc: hpa@zytor.com
Cc: andi@firstfloor.org
Cc: aswin@hp.com
Cc: scott.norton@hp.com
Cc: chegu_vinod@hp.com
Cc: Waiman.Long@hp.com
Cc: paulmck@linux.vnet.ibm.com
Cc: torvalds@linux-foundation.org
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1390936396-3962-3-git-send-email-jason.low2@hp.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-03-11 12:14:53 +01:00
..
cpu sched/preempt: Fix up missed PREEMPT_NEED_RESCHED folding 2014-01-13 17:38:55 +01:00
debug kgdb/kdb: Fix no KDB config problem 2014-01-25 08:55:09 +01:00
events This pull request has a new feature to ftrace, namely the trace event 2014-01-22 16:35:21 -08:00
gcov gcov: reuse kbasename helper 2013-11-13 12:09:34 +09:00
irq Merge branch 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2013-12-02 10:15:39 -08:00
locking locking/mutexes: Modify the way optimistic spinners are queued 2014-03-11 12:14:53 +01:00
power Merge branch 'for-3.14/core' of git://git.kernel.dk/linux-block 2014-01-30 11:19:05 -08:00
printk printk: flush conflicting continuation line 2014-01-23 16:36:56 -08:00
rcu Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2014-01-28 08:38:04 -08:00
sched Merge branch 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2014-01-31 09:02:51 -08:00
time Merge branch 'timers/core' of git://git.kernel.org/pub/scm/linux/kernel/git/frederic/linux-dynticks into timers/urgent 2014-01-25 08:27:26 +01:00
trace Merge branch 'for-3.14/core' of git://git.kernel.dk/linux-block 2014-01-30 11:19:05 -08:00
.gitignore Ignore generated file kernel/x509_certificate_list 2013-12-10 18:21:34 +00:00
acct.c
async.c
audit_tree.c fsnotify: remove pointless NULL initializers 2014-01-21 16:19:41 -08:00
audit_watch.c fsnotify: remove pointless NULL initializers 2014-01-21 16:19:41 -08:00
audit.c audit: fix location of __net_initdata for audit_net_ops 2014-01-17 17:14:32 -05:00
audit.h audit: Convert int limit uses to u32 2014-01-14 14:54:00 -05:00
auditfilter.c audit: log on errors from filter user rules 2014-01-13 22:32:31 -05:00
auditsc.c audit: fix dangling keywords in audit_log_set_loginuid() output 2014-01-13 22:32:38 -05:00
backtracetest.c
bounds.c mm: do not allocate page->ptl dynamically, if spinlock_t fits to long 2013-12-20 12:25:45 -08:00
capability.c audit: Simplify and correct audit_log_capset 2014-01-13 22:26:48 -05:00
cgroup_freezer.c cgroup: replace cftype->read_seq_string() with cftype->seq_show() 2013-12-05 12:28:04 -05:00
cgroup.c Merge branch 'for-3.14' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup 2014-01-21 17:51:34 -08:00
compat.c
configs.c
context_tracking.c context_tracking: Wrap static key check into more intuitive function name 2013-12-02 20:43:14 +01:00
cpu_pm.c
cpu.c Merge branch 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2013-11-14 16:55:11 +09:00
cpuset.c cgroup: replace cftype->read_seq_string() with cftype->seq_show() 2013-12-05 12:28:04 -05:00
crash_dump.c
cred.c
delayacct.c kernel/delayacct.c: remove redundant checking in __delayacct_add_tsk() 2013-11-13 12:09:12 +09:00
dma.c
elfcore.c switch elf_core_write_extra_phdrs() to dump_emit() 2013-11-09 00:16:23 -05:00
exec_domain.c
exit.c introduce for_each_thread() to replace the buggy while_each_thread() 2014-01-21 16:19:46 -08:00
extable.c kernel/extable: fix address-checks for core_kernel and init areas 2013-11-28 09:49:41 -08:00
fork.c exec: kill task_struct->did_exec 2014-01-23 16:37:02 -08:00
freezer.c libata, freezer: avoid block device removal while system is frozen 2013-12-19 13:50:32 -05:00
futex_compat.c
futex.c futex: Allow architectures to skip futex_atomic_cmpxchg_inatomic() test 2014-03-03 11:32:08 +01:00
groups.c userns: Kill nsown_capable it makes the wrong thing easy 2013-08-30 23:44:11 -07:00
hrtimer.c sched/deadline: Add SCHED_DEADLINE structures & implementation 2014-01-13 13:41:06 +01:00
hung_task.c hung_task: Display every hung task warning 2014-01-25 12:13:33 +01:00
irq_work.c
itimer.c
jump_label.c static_key: WARN on usage before jump_label_init was called 2013-10-19 19:45:35 -04:00
kallsyms.c
kcmp.c
Kconfig.freezer
Kconfig.hz kernel: remove CONFIG_USE_GENERIC_SMP_HELPERS 2013-11-15 09:32:22 +09:00
Kconfig.locks
Kconfig.preempt
kexec.c kernel/kexec.c: use vscnprintf() instead of vsnprintf() in vmcoreinfo_append_str() 2014-01-27 21:02:40 -08:00
kmod.c kernel/kmod.c: check for NULL in call_usermodehelper_exec() 2013-09-30 14:31:02 -07:00
kprobes.c kprobes: use KSYM_NAME_LEN to size identifier buffers 2013-11-13 12:09:26 +09:00
ksysfs.c kdump: fix exported size of vmcoreinfo note 2014-01-23 16:37:03 -08:00
kthread.c kthread: make kthread_create() killable 2013-11-13 12:08:59 +09:00
latencytop.c
Makefile KEYS: Remove files generated when SYSTEM_TRUSTED_KEYRING=y 2013-12-13 15:59:11 +00:00
module_signing.c keys: change asymmetric keys to use common hash definitions 2013-10-25 17:15:18 -04:00
module-internal.h KEYS: Separate the kernel signature checking keyring from module signing 2013-09-25 17:17:01 +01:00
module.c module: Add missing newline in printk call. 2014-01-21 09:59:16 +10:30
notifier.c
nsproxy.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace 2013-09-07 14:35:32 -07:00
padata.c padata: Fix wrong usage of rcu_dereference() 2013-12-05 21:28:42 +08:00
panic.c panic: Make panic_timeout configurable 2013-11-26 12:12:26 +01:00
params.c params: improve standard definitions 2013-12-04 14:09:46 +10:30
pid_namespace.c pid_namespace: make freeing struct pid_namespace rcu-delayed 2013-10-24 23:43:29 -04:00
pid.c pidns: fix free_pid() to handle the first fork failure 2013-09-30 14:31:03 -07:00
posix-cpu-timers.c posix-timers: Convert abuses of BUG_ON to WARN_ON 2013-12-09 16:56:29 +01:00
posix-timers.c
profile.c kernel: delete __cpuinit usage from all core kernel files 2013-07-14 19:36:59 -04:00
ptrace.c exec/ptrace: fix get_dumpable() incorrect tests 2013-11-13 12:09:33 +09:00
range.c
reboot.c kexec: migrate to reboot cpu 2013-12-18 19:04:50 -08:00
relay.c kernel: delete __cpuinit usage from all core kernel files 2013-07-14 19:36:59 -04:00
res_counter.c memcg: reduce function dereference 2013-09-12 15:38:02 -07:00
resource.c kernel/resource.c: remove the unneeded assignment in function __find_resource 2013-07-03 16:08:06 -07:00
seccomp.c
signal.c kernel/signal.c: change do_signal_stop/do_sigaction to use while_each_thread() 2014-01-23 16:37:02 -08:00
smp.c kernel/smp.c: remove cpumask_ipi 2014-01-30 16:56:54 -08:00
smpboot.c kernel: delete __cpuinit usage from all core kernel files 2013-07-14 19:36:59 -04:00
smpboot.h
softirq.c Merge branch 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2014-01-31 09:02:51 -08:00
stacktrace.c
stop_machine.c stop_machine: Fix race between stop_two_cpus() and stop_cpus() 2013-11-11 12:43:38 +01:00
sys_ni.c
sys.c kernel/sys.c: k_getrusage() can use while_each_thread() 2014-01-23 16:37:02 -08:00
sysctl_binary.c kernel/sysctl_binary.c: use scnprintf() instead of snprintf() 2013-11-13 12:09:33 +09:00
sysctl.c Merge branch 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2014-01-31 08:59:46 -08:00
system_certificates.S KEYS: correct alignment of system_certificate_list content in assembly file 2013-12-10 18:25:28 +00:00
system_keyring.c KEYS: correct alignment of system_certificate_list content in assembly file 2013-12-10 18:25:28 +00:00
task_work.c task_work: documentation 2013-09-11 15:58:27 -07:00
taskstats.c genetlink: only pass array to genl_register_family_with_ops() 2013-11-19 16:39:05 -05:00
test_kprobes.c
time.c
timeconst.bc
timer.c timer: Convert kmalloc_node(...GFP_ZERO...) to kzalloc_node(...) 2013-11-19 14:59:50 +01:00
tracepoint.c
tsacct.c
uid16.c userns: Kill nsown_capable it makes the wrong thing easy 2013-08-30 23:44:11 -07:00
up.c kernel: provide a __smp_call_function_single stub for !CONFIG_SMP 2013-11-15 09:32:22 +09:00
user_namespace.c KEYS: Add per-user_namespace registers for persistent per-UID kerberos caches 2013-09-24 10:35:19 +01:00
user-return-notifier.c
user.c KEYS: fix uninitialized persistent_keyring_register_sem 2013-12-13 15:59:11 +00:00
utsname_sysctl.c
utsname.c userns: Kill nsown_capable it makes the wrong thing easy 2013-08-30 23:44:11 -07:00
watchdog.c watchdog: update watchdog_thresh properly 2013-09-24 17:00:25 -07:00
workqueue_internal.h
workqueue.c Merge branch 'for-3.14' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq 2014-01-21 17:46:31 -08:00