Commit Graph

3891 Commits

Author SHA1 Message Date
Jiri Slaby
e17ba73b0e x86, generic: mark early_printk as asmlinkage
It's not explicitly marked as asmlinkage, but invoked from x86_32
startup code with parameters on stack.

No other architectures define early_printk and none of them are affected
by this change, since defines asmlinkage as empty token.

Signed-off-by: Jiri Slaby <jirislaby@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-06-18 13:11:01 +02:00
Ingo Molnar
87c8a64475 printk: export console_drivers
this symbol is needed by drivers/video/xen-fbfront.ko.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-06-16 09:15:58 +02:00
Nick Andrew
0915930805 printk: remember the message level for multi-line output
printk(KERN_ALERT "Danger Will Robinson!\nAlien Approaching!\n");

At present this will result in one message at ALERT level and one
at the current default message loglevel (e.g. WARNING). This is
non-intuitive.

Modify vprintk() to remember the message loglevel each time it
is specified and use it for subsequent lines of output which do
not specify one, within the same call to printk.

Signed-off-by: Nick Andrew <nick@nick-andrew.net>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-24 23:15:19 +02:00
Nick Andrew
ac60ad7413 printk: refactor processing of line severity tokens
Restructure the logic of vprintk() so the processing of the leading
3 characters of each input line is in one place, regardless whether
printk_time is enabled. This makes the code smaller and easier to
understand.

size reduction in kernel/printk.o:

   text	   data	    bss	    dec	    hex	filename
   6157	    397	1049804	1056358	 101e66	printk.o.before
   6117	    397	1049804	1056318	 101e3e	printk.o.after

and some style uncleanlinesses removed as well as a side-effect:

 Before:
    total: 19 errors, 22 warnings, 1340 lines checked
 After:
    total: 17 errors, 22 warnings, 1333 lines checked

Signed-off-by: Nick Andrew <nick@nick-andrew.net>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-24 23:15:12 +02:00
Jan Kiszka
cd3a1b8562 printk: don't prefer unsuited consoles on registration
console election: If some console happens to be registered first which does
not provide a tty binding (!console->device), it prevents that more suited
consoles which are registered later on can enter the candidate pool for
console_device().  This is observable with KGDB's console which may already
be registered (and exploited!) during early debugger connections, that is
before any regular console registration.

This patch fixes the issue by postponing the final, automated
preferred_console selection until someone with a non-NULL device handler
comes around.

Signed-off-by: Jan Kiszka <jan.kiszka@web.de>
Cc: Jason Wessel <jason.wessel@windriver.com>
Cc: Gerd Hoffmann <kraxel@suse.de>
Cc: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-24 23:15:07 +02:00
Tejun Heo
3b8945e8d4 printk: clean up recursion check related static variables
Make printk_recursion_bug_msg static and drop printk prefix from recursion
variables.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-24 23:15:02 +02:00
Thomas Gleixner
42fdfa238a namespacecheck: more kernel/printk.c fixes
[ Stephen Rothwell <sfr@canb.auug.org.au>: build fix ]

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-24 23:14:51 +02:00
Thomas Gleixner
7f6f3a39d2 namespacecheck: fix kernel printk.c
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-24 23:12:18 +02:00
Linus Torvalds
16ae527bfa Merge branch 'audit.b51' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/audit-current
* 'audit.b51' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/audit-current:
  [PATCH] list_for_each_rcu must die: audit
  [patch 1/1] audit_send_reply(): fix error-path memory leak
  [PATCH] open sessionid permissions
2008-05-19 16:38:10 -07:00
Paul E. McKenney
6793a051fb [PATCH] list_for_each_rcu must die: audit
All uses of list_for_each_rcu() can be profitably replaced by the
easier-to-use list_for_each_entry_rcu().  This patch makes this change
for the Audit system, in preparation for removing the list_for_each_rcu()
API entirely.  This time with well-formed SOB.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2008-05-17 03:30:23 -04:00
Andrew Morton
fcaf1eb868 [patch 1/1] audit_send_reply(): fix error-path memory leak
Addresses http://bugzilla.kernel.org/show_bug.cgi?id=10663

Reporter: Daniel Marjamki <danielm77@spray.se>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2008-05-17 03:30:22 -04:00
Al Viro
eceea0b3df [PATCH] avoid multiplication overflows and signedness issues for max_fds
Limit sysctl_nr_open - we don't want ->max_fds to exceed MAX_INT and
we don't want size calculation for ->fd[] to overflow.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2008-05-16 17:22:52 -04:00
Al Viro
02afc6267f [PATCH] dup_fd() fixes, part 1
Move the sucker to fs/file.c in preparation to the rest

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2008-05-16 17:22:26 -04:00
Harvey Harrison
3fc957721d lib: create common ascii hex array
Add a common hex array in hexdump.c so everyone can use it.

Add a common hi/lo helper to avoid the shifting masking that is
done to get the upper and lower nibbles of a byte value.

Pull the pack_hex_byte helper from kgdb as it is opencoded many
places in the tree that will be consolidated.

Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com>
Acked-by: Paul Mundt <lethal@linux-sh.org>
Cc: Jason Wessel <jason.wessel@windriver.com>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-05-14 19:11:14 -07:00
Mirco Tischler
0c70814c31 cgroups: fix compile warning
Return type of cpu_rt_runtime_write() should be int instead of ssize_t.

Signed-off-by: Mirco Tischler <mt-ml@gmx.de>
Acked-by: Paul Menage <menage@google.com>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-05-14 19:11:14 -07:00
Linus Torvalds
c3921ab715 Add new 'cond_resched_bkl()' helper function
It acts exactly like a regular 'cond_resched()', but will not get
optimized away when CONFIG_PREEMPT is set.

Normal kernel code is already preemptable in the presense of
CONFIG_PREEMPT, so cond_resched() is optimized away (see commit
02b67cc3ba "sched: do not do
cond_resched() when CONFIG_PREEMPT").

But when wanting to conditionally reschedule while holding a lock, you
need to use "cond_sched_lock(lock)", and the new function is the BKL
equivalent of that.

Also make fs/locks.c use it.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-05-11 16:04:48 -07:00
Linus Torvalds
8e3e076c5a BKL: revert back to the old spinlock implementation
The generic semaphore rewrite had a huge performance regression on AIM7
(and potentially other BKL-heavy benchmarks) because the generic
semaphores had been rewritten to be simple to understand and fair.  The
latter, in particular, turns a semaphore-based BKL implementation into a
mess of scheduling.

The attempt to fix the performance regression failed miserably (see the
previous commit 00b41ec261 'Revert
"semaphore: fix"'), and so for now the simple and sane approach is to
instead just go back to the old spinlock-based BKL implementation that
never had any issues like this.

This patch also has the advantage of being reported to fix the
regression completely according to Yanmin Zhang, unlike the semaphore
hack which still left a couple percentage point regression.

As a spinlock, the BKL obviously has the potential to be a latency
issue, but it's not really any different from any other spinlock in that
respect.  We do want to get rid of the BKL asap, but that has been the
plan for several years.

These days, the biggest users are in the tty layer (open/release in
particular) and Alan holds out some hope:

  "tty release is probably a few months away from getting cured - I'm
   afraid it will almost certainly be the very last user of the BKL in
   tty to get fixed as it depends on everything else being sanely locked."

so while we're not there yet, we do have a plan of action.

Tested-by: Yanmin Zhang <yanmin_zhang@linux.intel.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Matthew Wilcox <matthew@wil.cx>
Cc: Alexander Viro <viro@ftp.linux.org.uk>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-05-10 20:58:02 -07:00
Linus Torvalds
00b41ec261 Revert "semaphore: fix"
This reverts commit bf726eab37, as it has
been reported to cause a regression with processes stuck in __down(),
apparently because some missing wakeup.

Quoth Sven Wegener:
 "I'm currently investigating a regression that has showed up with my
  last git pull yesterday.  Bisecting the commits showed bf726e
  "semaphore: fix" to be the culprit, reverting it fixed the issue.

  Symptoms: During heavy filesystem usage (e.g.  a kernel compile) I get
  several compiler processes in uninterruptible sleep, blocking all i/o
  on the filesystem.  System is an Intel Core 2 Quad running a 64bit
  kernel and userspace.  Filesystem is xfs on top of lvm.  See below for
  the output of sysrq-w."

See

	http://lkml.org/lkml/2008/5/10/45

for full report.

In the meantime, we can just fix the BKL performance regression by
reverting back to the good old BKL spinlock implementation instead,
since any sleeping lock will generally perform badly, especially if it
tries to be fair.

Reported-by: Sven Wegener <sven.wegener@stealer.net>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-05-10 20:43:22 -07:00
Rusty Russell
91e37a793b module: don't ignore vermagic string if module doesn't have modversions
Linus found a logic bug: we ignore the version number in a module's
vermagic string if we have CONFIG_MODVERSIONS set, but modversions
also lets through a module with no __versions section for modprobe
--force (with tainting, but still).

We should only ignore the start of the vermagic string if the module
actually *has* crcs to check.  Rather than (say) having an
entertaining hissy fit and creating a config option to work around the
buggy code.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-05-09 07:45:18 -07:00
Rusty Russell
a5dd697074 module: be more picky about allowing missing module versions
We allow missing __versions sections, because modprobe --force strips
it.  It makes less sense to allow sections where there's no version
for a specific symbol the module uses, so disallow that.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-05-09 07:45:18 -07:00
Linus Torvalds
c4f51b4662 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mingo/linux-2.6-sched-fixes
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mingo/linux-2.6-sched-fixes:
  sched: fix weight calculations
  semaphore: fix
2008-05-08 11:31:07 -07:00
Linus Torvalds
7a34912d90 Merge branch 'for-linus' of git://git.kernel.dk/linux-2.6-block
* 'for-linus' of git://git.kernel.dk/linux-2.6-block:
  Revert "relay: fix splice problem"
  docbook: fix bio missing parameter
  block: use unitialized_var() in bio_alloc_bioset()
  block: avoid duplicate calls to get_part() in disk stat code
  cfq-iosched: make io priorities inherit CPU scheduling class as well as nice
  block: optimize generic_unplug_device()
  block: get rid of likely/unlikely predictions in merge logic
  vfs: splice remove_suid() cleanup
  cfq-iosched: fix RCU race in the cfq io_context destructor handling
  block: adjust tagging function queue bit locking
  block: sysfs store function needs to grab queue_lock and use queue_flag_*()
2008-05-08 10:48:36 -07:00
Paul Menage
5be7a4792a Fix cpuset sched_relax_domain_level control file
Due to a merge conflict, the sched_relax_domain_level control file was marked
as being handled by cpuset_read/write_u64, but the code to handle it was
actually in cpuset_common_file_read/write.

Since the value being written/read is in fact a signed integer, it should be
treated as such; this patch adds cpuset_read/write_s64 functions, and uses
them to handle the sched_relax_domain_level file.

With this patch, the sched_relax_domain_level can be read and written, and the
correct contents seen/updated.

Signed-off-by: Paul Menage <menage@google.com>
Cc: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Cc: Paul Jackson <pj@sgi.com>
Cc: Ingo Molnar <mingo@elte.hu>
Reviewed-by: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-05-08 10:46:56 -07:00
Mike Galbraith
46151122e0 sched: fix weight calculations
The conversion between virtual and real time is as follows:

  dvt = rw/w * dt <=> dt = w/rw * dvt

Since we want the fair sleeper granularity to be in real time, we actually
need to do:

  dvt = - rw/w * l

This bug could be related to the regression reported by Yanmin Zhang:

| Comparing with kernel 2.6.25, sysbench+mysql(oltp, readonly) has lots
| of regressions with 2.6.26-rc1:
|
| 1) 8-core stoakley: 28%;
| 2) 16-core tigerton: 20%;
| 3) Itanium Montvale: 50%.

Reported-by: "Zhang, Yanmin" <yanmin_zhang@linux.intel.com>
Signed-off-by: Mike Galbraith <efault@gmx.de>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-05-08 17:00:42 +02:00
Ingo Molnar
bf726eab37 semaphore: fix
Yanmin Zhang reported:

| Comparing with kernel 2.6.25, AIM7 (use tmpfs) has more th
| regression under 2.6.26-rc1 on my 8-core stoakley, 16-core tigerton,
| and Itanium Montecito. Bisect located the patch below:
|
| 64ac24e738 is first bad commit
| commit 64ac24e738
| Author: Matthew Wilcox <matthew@wil.cx>
| Date:   Fri Mar 7 21:55:58 2008 -0500
|
|     Generic semaphore implementation
|
| After I manually reverted the patch against 2.6.26-rc1 while fixing
| lots of conflicts/errors, aim7 regression became less than 2%.

i reproduced the AIM7 workload and can confirm Yanmin's findings that
-.26-rc1 regresses over .25 - by over 67% here.

Looking at the workload i found and fixed what i believe to be the real
bug causing the AIM7 regression: it was inefficient wakeup / scheduling
/ locking behavior of the new generic semaphore code, causing suboptimal
performance.

The problem comes from the following code. The new semaphore code does
this on down():

        spin_lock_irqsave(&sem->lock, flags);
        if (likely(sem->count > 0))
                sem->count--;
        else
                __down(sem);
        spin_unlock_irqrestore(&sem->lock, flags);

and this on up():

        spin_lock_irqsave(&sem->lock, flags);
        if (likely(list_empty(&sem->wait_list)))
                sem->count++;
        else
                __up(sem);
        spin_unlock_irqrestore(&sem->lock, flags);

where __up() does:

        list_del(&waiter->list);
        waiter->up = 1;
        wake_up_process(waiter->task);

and where __down() does this in essence:

        list_add_tail(&waiter.list, &sem->wait_list);
        waiter.task = task;
        waiter.up = 0;
        for (;;) {
                [...]
                spin_unlock_irq(&sem->lock);
                timeout = schedule_timeout(timeout);
                spin_lock_irq(&sem->lock);
                if (waiter.up)
                        return 0;
        }

the fastpath looks good and obvious, but note the following property of
the contended path: if there's a task on the ->wait_list, the up() of
the current owner will "pass over" ownership to that waiting task, in a
wake-one manner, via the waiter->up flag and by removing the waiter from
the wait list.

That is all and fine in principle, but as implemented in
kernel/semaphore.c it also creates a nasty, hidden source of contention!

The contention comes from the following property of the new semaphore
code: the new owner owns the semaphore exclusively, even if it is not
running yet.

So if the old owner, even if just a few instructions later, does a
down() [lock_kernel()] again, it will be blocked and will have to wait
on the new owner to eventually be scheduled (possibly on another CPU)!
Or if another task gets to lock_kernel() sooner than the "new owner"
scheduled, it will be blocked unnecessarily and for a very long time
when there are 2000 tasks running.

I.e. the implementation of the new semaphores code does wake-one and
lock ownership in a very restrictive way - it does not allow
opportunistic re-locking of the lock at all and keeps the scheduler from
picking task order intelligently.

This kind of scheduling, with 2000 AIM7 processes running, creates awful
cross-scheduling between those 2000 tasks, causes reduced parallelism, a
throttled runqueue length and a lot of idle time. With increasing number
of CPUs it causes an exponentially worse behavior in AIM7, as the chance
for a newly woken new-owner task to actually run anytime soon is less
and less likely.

Note that it takes just a tiny bit of contention for the 'new-semaphore
catastrophy' to happen: the wakeup latencies get added to whatever small
contention there is, and quickly snowball out of control!

I believe Yanmin's findings and numbers support this analysis too.

The best fix for this problem is to use the same scheduling logic that
the kernel/mutex.c code uses: keep the wake-one behavior (that is OK and
wanted because we do not want to over-schedule), but also allow
opportunistic locking of the lock even if a wakee is already "in
flight".

The patch below implements this new logic. With this patch applied the
AIM7 regression is largely fixed on my quad testbox:

  # v2.6.25 vanilla:
  ..................
  Tasks   Jobs/Min        JTI     Real    CPU     Jobs/sec/task
  2000    56096.4         91      207.5   789.7   0.4675
  2000    55894.4         94      208.2   792.7   0.4658

  # v2.6.26-rc1-166-gc0a1811 vanilla:
  ...................................
  Tasks   Jobs/Min        JTI     Real    CPU     Jobs/sec/task
  2000    33230.6         83      350.3   784.5   0.2769
  2000    31778.1         86      366.3   783.6   0.2648

  # v2.6.26-rc1-166-gc0a1811 + semaphore-speedup:
  ...............................................
  Tasks   Jobs/Min        JTI     Real    CPU     Jobs/sec/task
  2000    55707.1         92      209.0   795.6   0.4642
  2000    55704.4         96      209.0   796.0   0.4642

i.e. a 67% speedup. We are now back to within 1% of the v2.6.25
performance levels and have zero idle time during the test, as expected.

Btw., interactivity also improved dramatically with the fix - for
example console-switching became almost instantaneous during this
workload (which after all is running 2000 tasks at once!), without the
patch it was stuck for a minute at times.

There's another nice side-effect of this speedup patch, the new generic
semaphore code got even smaller:

   text    data     bss     dec     hex filename
   1241       0       0    1241     4d9 semaphore.o.before
   1207       0       0    1207     4b7 semaphore.o.after

(because the waiter.up complication got removed.)

Longer-term we should look into using the mutex code for the generic
semaphore code as well - but i's not easy due to legacies and it's
outside of the scope of v2.6.26 and outside the scope of this patch as
well.

Bisected-by: "Zhang, Yanmin" <yanmin_zhang@linux.intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-05-08 17:00:42 +02:00
Jens Axboe
75065ff619 Revert "relay: fix splice problem"
This reverts commit c3270e577c.
2008-05-08 14:06:19 +02:00
Peter Zijlstra
3e51f33fcc sched: add optional support for CONFIG_HAVE_UNSTABLE_SCHED_CLOCK
this replaces the rq->clock stuff (and possibly cpu_clock()).

 - architectures that have an 'imperfect' hardware clock can set
   CONFIG_HAVE_UNSTABLE_SCHED_CLOCK

 - the 'jiffie' window might be superfulous when we update tick_gtod
   before the __update_sched_clock() call in sched_clock_tick()

 - cpu_clock() might be implemented as:

     sched_clock_cpu(smp_processor_id())

   if the accuracy proves good enough - how far can TSC drift in a
   single jiffie when considering the filtering and idle hooks?

[ mingo@elte.hu: various fixes and cleanups ]

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-05-05 23:56:18 +02:00
Ingo Molnar
dfbf4a1bc3 sched: fix cpu clock
David Miller pointed it out that nothing in cpu_clock() sets
prev_cpu_time. This caused __sync_cpu_clock() to be called
all the time - against the intention of this code.

The result was that in practice we hit a global spinlock every
time cpu_clock() is called - which - even though cpu_clock()
is used for tracing and debugging, is suboptimal.

While at it, also:

- move the irq disabling to the outest layer,
  this should make cpu_clock() warp-free when called with irqs
  enabled.

- use long long instead of cycles_t - for platforms where cycles_t
  is 32-bit.

Reported-by: David Miller <davem@davemloft.net>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-05-05 23:56:18 +02:00
Miao Xie
cb4ad1ffc7 sched: fair-group: fix a Div0 error of the fair group scheduler
When I echoed 0 into the "cpu.shares" file, a Div0 error occured.

We found it is caused by the following calling.

   sched_group_set_shares(tg, shares)
       set_se_shares(tg->se[i], shares/nr_cpu_ids)
           __set_se_shares(se, shares)
               div64_64((1ULL<<32), shares)

When the echoed value was less than the number of processores, the result of the
sentence "shares/nr_cpu_ids" was 0, and then the system called div64() to divide
the result, the Div0 error occured.

It is unnecessary that the shares value is divided by nr_cpu_ids, I think.
Because in the function  __update_group_shares_cpu() and init_tg_cfs_entry(),
the shares value isn't divided by nr_cpu_ids when setting shares of the sched
entity.

This patch fixes this bug. And echoing ULONG_MAX value into cpu.shares also
causes Div0 error, so we set a macro MAX_SHARES to limit the max value of
shares.

Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-05-05 23:56:18 +02:00
Heiko Carstens
712555ee4f sched: fix missing locking in sched_domains code
Concurrent calls to detach_destroy_domains and arch_init_sched_domains
were prevented by the old scheduler subsystem cpu hotplug mutex. When
this got converted to get_online_cpus() the locking got broken.
Unlike before now several processes can concurrently enter the critical
sections that were protected by the old lock.

So use the already present doms_cur_mutex to protect these sections again.

Cc: Gautham R Shenoy <ego@in.ibm.com>
Cc: Paul Jackson <pj@sgi.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-05-05 23:56:18 +02:00
Ingo Molnar
690229a091 sched: make clock sync tunable by architecture code
make time_sync_thresh tunable to architecture code.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-05-05 23:56:18 +02:00
Mike Galbraith
d7dcdc11cf sched: fix debugging
Revert debugging commit 7ba2e74ab5.
print_cfs_rq_tasks() can induce live-lock if a task is dequeued
during list traversal.

Signed-off-by: Mike Galbraith <efault@gmx.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-05-05 23:56:18 +02:00
David Simner
673a90a1e0 sched: fix sched_info_switch not being called according to documentation
http://bugzilla.kernel.org/show_bug.cgi?id=10545

sched_stats.h says that __sched_info_switch is "called when prev !=
next" in the comment.  sched.c should therefore do that.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-05-05 23:56:18 +02:00
Peter Zijlstra
b328ca182f sched: fix hrtick_start_fair and CPU-Hotplug
Gautham R Shenoy reported:

 > While running the usual CPU-Hotplug stress tests on linux-2.6.25,
 > I noticed the following in the console logs.
 >
 > This is a wee bit difficult to reproduce. In the past 10 runs I hit this
 > only once.
 >
 > ------------[ cut here ]------------
 >
 > WARNING: at kernel/sched.c:962 hrtick+0x2e/0x65()
 >
 > Just wondering if we are doing a good job at handling the cancellation
 > of any per-cpu scheduler timers during CPU-Hotplug.

This looks like its indeed not cancelled at all and migrates the it to
another cpu. Fix it via a proper hotplug notifier mechanism.

Reported-by: Gautham R Shenoy <ego@in.ibm.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: stable@kernel.org
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-05-05 23:56:18 +02:00
Gregory Haskins
104f64549c sched: fix SCHED_FAIR wake-idle logic error
We currently use an optimization to skip the overhead of wake-idle
processing if more than one task is assigned to a run-queue.  The
assumption is that the system must already be load-balanced or we
wouldnt be overloaded to begin with.

The problem is that we are looking at rq->nr_running, which may include
RT tasks in addition to CFS tasks.  Since the presence of RT tasks
really has no bearing on the balance status of CFS tasks, this throws
the calculation off.

This patch changes the logic to only consider the number of CFS tasks
when making the decision to optimze the wake-idle.

Signed-off-by: Gregory Haskins <ghaskins@novell.com>
CC: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-05-05 23:56:18 +02:00
Gregory Haskins
8ae121ac86 sched: fix RT task-wakeup logic
Dmitry Adamushko pointed out a logic error in task_wake_up_rt() where we
will always evaluate to "true".  You can find the thread here:

http://lkml.org/lkml/2008/4/22/296

In reality, we only want to try to push tasks away when a wake up request is
not going to preempt the current task.  So lets fix it.

Note: We introduce test_tsk_need_resched() instead of open-coding the flag
check so that the merge-conflict with -rt should help remind us that we
may need to support NEEDS_RESCHED_DELAYED in the future, too.

Signed-off-by: Gregory Haskins <ghaskins@novell.com>
CC: Dmitry Adamushko <dmitry.adamushko@gmail.com>
CC: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-05-05 23:56:18 +02:00
Harvey Harrison
983ed7a66b sched: add statics, don't return void expressions
Noticed by sparse:
kernel/sched.c:760:20: warning: symbol 'sched_feat_names' was not declared. Should it be static?
kernel/sched.c:767:5: warning: symbol 'sched_feat_open' was not declared. Should it be static?
kernel/sched_fair.c:845:3: warning: returning void-valued expression
kernel/sched.c:4386:3: warning: returning void-valued expression

Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-05-05 23:56:17 +02:00
Andrew Morton
d478c2cfaa sched: add debug checks to idle functions
Cc: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Cc: "Justin Mattock" <justinmattock@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-05-05 23:56:17 +02:00
Harvey Harrison
2abdad0a4c sched: make rt_sched_class, idle_sched_class static
The C files are included directly in sched.c, so they are
effectively static.

Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-05-05 23:56:17 +02:00
Peter Zijlstra
e05510d01a sched: optimize calc_delta_mine()
Joel noticed that the !lw->inv_weight contition isn't unlikely anymore so
remove the unlikely annotation. Also, remove the two div64_u64() inv_weight
calculations, which makes them rely on the calc_delta_mine() path as well.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
CC: Joel Schopp <jschopp@austin.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-05-05 23:56:17 +02:00
Peter Zijlstra
a992241de6 sched: fix normalized sleeper
Normalized sleeper uses calc_delta*() which requires that the rq load is
already updated, so move account_entity_enqueue() before place_entity()

Tested-by: Frans Pop <elendil@planet.nl>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-05-05 23:56:17 +02:00
Linus Torvalds
5717922a1b Merge branch 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jwessel/linux-2.6-kgdb
* 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jwessel/linux-2.6-kgdb:
  kgdb: kconfig fix xconfig/menuconfig element
  kgdb: fix signedness mixmatches, add statics, add declaration to header
  kgdb: 1000 loops for the single step test in kgdbts
  kgdb: trivial sparse fixes in kgdb test-suite
  kgdb: minor documentation fixes
2008-05-05 10:17:30 -07:00
Eric Sesterhenn
82af7aca56 Removal of FUTEX_FD
Since FUTEX_FD was scheduled for removal in June 2007 lets remove it.

Google Code search found no users for it and NGPT was abandoned in 2003
according to IBM.  futex.h is left untouched to make sure the id does
not get reassigned.  Since queue_me() has no users left it is commented
out to avoid a warning, i didnt remove it completely since it is part of
the internal api (matching unqueue_me())

Signed-off-by: Eric Sesterhenn <snakebyte@gmx.de>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> (removed rest)
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-05-05 08:18:45 -07:00
Harvey Harrison
688b744d8b kgdb: fix signedness mixmatches, add statics, add declaration to header
Noticed by sparse:
arch/x86/kernel/kgdb.c:556:15: warning: symbol 'kgdb_arch_pc' was not declared. Should it be static?
kernel/kgdb.c:149:8: warning: symbol 'kgdb_do_roundup' was not declared. Should it be static?
kernel/kgdb.c:193:22: warning: symbol 'kgdb_arch_pc' was not declared. Should it be static?
kernel/kgdb.c:712:5: warning: symbol 'remove_all_break' was not declared. Should it be static?

Related to kgdb_hex2long:
arch/x86/kernel/kgdb.c:371:28: warning: incorrect type in argument 2 (different signedness)
arch/x86/kernel/kgdb.c:371:28:    expected long *long_val
arch/x86/kernel/kgdb.c:371:28:    got unsigned long *<noident>
kernel/kgdb.c:469:27: warning: incorrect type in argument 2 (different signedness)
kernel/kgdb.c:469:27:    expected long *long_val
kernel/kgdb.c:469:27:    got unsigned long *<noident>
kernel/kgdb.c:470:27: warning: incorrect type in argument 2 (different signedness)
kernel/kgdb.c:470:27:    expected long *long_val
kernel/kgdb.c:470:27:    got unsigned long *<noident>
kernel/kgdb.c:894:27: warning: incorrect type in argument 2 (different signedness)
kernel/kgdb.c:894:27:    expected long *long_val
kernel/kgdb.c:894:27:    got unsigned long *<noident>
kernel/kgdb.c:895:27: warning: incorrect type in argument 2 (different signedness)
kernel/kgdb.c:895:27:    expected long *long_val
kernel/kgdb.c:895:27:    got unsigned long *<noident>
kernel/kgdb.c:1127:28: warning: incorrect type in argument 2 (different signedness)
kernel/kgdb.c:1127:28:    expected long *long_val
kernel/kgdb.c:1127:28:    got unsigned long *<noident>
kernel/kgdb.c:1132:25: warning: incorrect type in argument 2 (different signedness)
kernel/kgdb.c:1132:25:    expected long *long_val
kernel/kgdb.c:1132:25:    got unsigned long *<noident>

Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com>
Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
2008-05-05 07:13:21 -05:00
Linus Torvalds
826e4506a0 Make forced module loading optional
The kernel module loader used to be much too happy to allow loading of
modules for the wrong kernel version by default.  For example, if you
had MODVERSIONS enabled, but tried to load a module with no version
info, it would happily load it and taint the kernel - whether it was
likely to actually work or not!

Generally, such forced module loading should be considered a really
really bad idea, so make it conditional on a new config option
(MODULE_FORCE_LOAD), and make it default to off.

If somebody really wants to force module loads, that's their problem,
but we should not encourage it.  Especially as it happened to me by
mistake (ie regular unversioned Fedora modules getting loaded) causing
lots of strange behavior.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-05-04 17:04:16 -07:00
Linus Torvalds
afa26be86b Merge git://git.kernel.org/pub/scm/linux/kernel/git/tglx/linux-2.6-hrt
* git://git.kernel.org/pub/scm/linux/kernel/git/tglx/linux-2.6-hrt:
  clocksource: allow read access to available/current_clocksource
  clocksource: Fix permissions for available_clocksource
  hrtimer: remove duplicate helper function
2008-05-03 13:51:10 -07:00
Heiko Carstens
4f95f81a48 clocksource: allow read access to available/current_clocksource
There is no harm, when users can read the info and we ask often enough
during debugging for this kind of information.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: John Stultz <johnstul@us.ibm.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-03 18:11:48 +02:00
Heiko Carstens
4359a023a8 clocksource: Fix permissions for available_clocksource
File permissions for
/sys/devices/system/clocksource/clocksource0/available_clocksource
are 600 which allows write access. But this is in fact a read only
file. So change permissions to 400.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: John Stultz <johnstul@us.ibm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-03 18:11:48 +02:00
Oliver Hartkopp
4346f65426 hrtimer: remove duplicate helper function
The helper function hrtimer_callback_running() is used in
kernel/hrtimer.c as well as in the updated net/can/bcm.c which now
supports hrtimers. Moving the helper function to hrtimer.h removes the
duplicate definition in the C-files.

Signed-off-by: Oliver Hartkopp <oliver@hartkopp.net>
Cc: David Miller <davem@davemloft.net>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-03 18:11:48 +02:00
H. Peter Anvin
b9095fd8a7 Make constants in kernel/timeconst.h fixed 64 bits
Force constants in kernel/timeconst.h (except shift counts) to be 64 bits,
using U64_C() constructor macros, and eliminate constants that cannot
be represented at all in 64 bits.  This avoids warnings with some gcc
versions.

Drop generating 64-bit constants, since we have no real hope of
getting a full set (operation on 64-bit values requires a 128-bit
intermediate result, which gcc only supports on 64-bit platforms, and
only with libgcc support on some.)  Note that the use of these
constants does not depend on if we are on a 32- or 64-bit architecture.

This resolves Bugzilla 10153.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2008-05-02 16:18:42 -07:00