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  1. 21 1月, 2010 1 次提交
  3. 23 12月, 2009 1 次提交
  5. 21 12月, 2009 2 次提交
  7. 17 12月, 2009 12 次提交
    • P
      sched: Fix broken assertion · 077614ee
      由 Peter Zijlstra 提交于 
      There's a preemption race in the set_task_cpu() debug check in
that when we get preempted after setting task->state we'd still
be on the rq proper, but fail the test.

Check for preempted tasks, since those are always on the RQ.
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <20091217121830.137155561@chello.nl>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
      077614ee
    • F
      sched: Teach might_sleep() about preemptible RCU · 234da7bc
      由 Frederic Weisbecker 提交于 
      In practice, it is harmless to voluntarily sleep in a
rcu_read_lock() section if we are running under preempt rcu, but
it is illegal if we build a kernel running non-preemptable rcu.

Currently, might_sleep() doesn't notice sleepable operations
under rcu_read_lock() sections if we are running under
preemptable rcu because preempt_count() is left untouched after
rcu_read_lock() in this case. But we want developers who test
their changes under such config to notice the "sleeping while
atomic" issues.

So we add rcu_read_lock_nesting to prempt_count() in
might_sleep() checks.

[ v2: Handle rcu-tiny ]
Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>
Reviewed-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
LKML-Reference: <1260991265-8451-1-git-send-regression-fweisbec@gmail.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
      234da7bc
    • I
      sched: Make warning less noisy · 416eb395
      由 Ingo Molnar 提交于 
      Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
LKML-Reference: <20091216170517.807938893@chello.nl>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
      416eb395
    • P
      sched: Simplify set_task_cpu() · 738d2be4
      由 Peter Zijlstra 提交于 
      Rearrange code a bit now that its a simpler function.
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
LKML-Reference: <20091216170518.269101883@chello.nl>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
      738d2be4
    • P
      sched: Remove the cfs_rq dependency from set_task_cpu() · 88ec22d3
      由 Peter Zijlstra 提交于 
      In order to remove the cfs_rq dependency from set_task_cpu() we
need to ensure the task is cfs_rq invariant for all callsites.

The simple approach is to substract cfs_rq->min_vruntime from
se->vruntime on dequeue, and add cfs_rq->min_vruntime on
enqueue.

However, this has the downside of breaking FAIR_SLEEPERS since
we loose the old vruntime as we only maintain the relative
position.

To solve this, we observe that we only migrate runnable tasks,
we do this using deactivate_task(.sleep=0) and
activate_task(.wakeup=0), therefore we can restrain the
min_vruntime invariance to that state.

The only other case is wakeup balancing, since we want to
maintain the old vruntime we cannot make it relative on dequeue,
but since we don't migrate inactive tasks, we can do so right
before we activate it again.

This is where we need the new pre-wakeup hook, we need to call
this while still holding the old rq->lock. We could fold it into
->select_task_rq(), but since that has multiple callsites and
would obfuscate the locking requirements, that seems like a
fudge.

This leaves the fork() case, simply make sure that ->task_fork()
leaves the ->vruntime in a relative state.

This covers all cases where set_task_cpu() gets called, and
ensures it sees a relative vruntime.
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
LKML-Reference: <20091216170518.191697025@chello.nl>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
      88ec22d3
    • P
      sched: Add pre and post wakeup hooks · efbbd05a
      由 Peter Zijlstra 提交于 
      As will be apparent in the next patch, we need a pre wakeup hook
for sched_fair task migration, hence rename the post wakeup hook
and one pre wakeup.
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
LKML-Reference: <20091216170518.114746117@chello.nl>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
      efbbd05a
    • P
      sched: Move kthread_bind() back to kthread.c · 881232b7
      由 Peter Zijlstra 提交于 
      Since kthread_bind() lost its dependencies on sched.c, move it
back where it came from.
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
LKML-Reference: <20091216170518.039524041@chello.nl>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
      881232b7
    • P
      sched: Fix select_task_rq() vs hotplug issues · 5da9a0fb
      由 Peter Zijlstra 提交于 
      Since select_task_rq() is now responsible for guaranteeing
->cpus_allowed and cpu_active_mask, we need to verify this.

select_task_rq_rt() can blindly return
smp_processor_id()/task_cpu() without checking the valid masks,
select_task_rq_fair() can do the same in the rare case that all
SD_flags are disabled.
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
LKML-Reference: <20091216170517.961475466@chello.nl>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
      5da9a0fb
    • P
      sched: Fix sched_exec() balancing · 38022906
      由 Peter Zijlstra 提交于 
      Since we access ->cpus_allowed without holding rq->lock we need
a retry loop to validate the result, this comes for near free
when we merge sched_migrate_task() into sched_exec() since that
already does the needed check.
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
LKML-Reference: <20091216170517.884743662@chello.nl>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
      38022906
    • P
      sched: Ensure set_task_cpu() is never called on blocked tasks · e2912009
      由 Peter Zijlstra 提交于 
      In order to clean up the set_task_cpu() rq dependencies we need
to ensure it is never called on blocked tasks because such usage
does not pair with consistent rq->lock usage.

This puts the migration burden on ttwu().

Furthermore we need to close a race against changing
->cpus_allowed, since select_task_rq() runs with only preemption
disabled.

For sched_fork() this is safe because the child isn't in the
tasklist yet, for wakeup we fix this by synchronizing
set_cpus_allowed_ptr() against TASK_WAKING, which leaves
sched_exec to be a problem

This also closes a hole in (6ad4c188 sched: Fix balance vs
hotplug race) where ->select_task_rq() doesn't validate the
result against the sched_domain/root_domain.
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
LKML-Reference: <20091216170517.807938893@chello.nl>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
      e2912009
    • P
      sched: Use TASK_WAKING for fork wakups · 06b83b5f
      由 Peter Zijlstra 提交于 
      For later convenience use TASK_WAKING for fresh tasks.
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
LKML-Reference: <20091216170517.732561278@chello.nl>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
      06b83b5f
    • P
      sched: Fix task_hot() test order · e6c8fba7
      由 Peter Zijlstra 提交于 
      Make sure not to access sched_fair fields before verifying it is
indeed a sched_fair task.
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
CC: stable@kernel.org
LKML-Reference: <20091216170517.577998058@chello.nl>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
      e6c8fba7
  9. 15 12月, 2009 8 次提交
  11. 13 12月, 2009 2 次提交
    • J
      sched: Use pr_fmt() and pr_<level>() · 663997d4
      由 Joe Perches 提交于 
      - Convert printk(KERN_<level> to pr_<level> (not KERN_DEBUG)
 - Add #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 - Coalesce long format strings
 - Add missing \n to "ERROR: !SD_LOAD_BALANCE domain has parent"
Signed-off-by: NJoe Perches <joe@perches.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <1260655047.2637.7.camel@Joe-Laptop.home>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
      663997d4
    • R
      sched: Make wakeup side and atomic variants of completion API irq safe · 7539a3b3
      由 Rafael J. Wysocki 提交于 
      Alan Stern noticed that all the wakeup side (and atomic) variants of the
completion APIs should be irq safe, but the newly introduced
completion_done() and try_wait_for_completion() aren't. The use of the
irq unsafe variants in IRQ contexts can cause crashes/hangs.

Fix the problem by making them use spin_lock_irqsave() and
spin_lock_irqrestore().
Reported-by: NAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: NRafael J. Wysocki <rjw@sisk.pl>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Zhang Rui <rui.zhang@intel.com>
Cc: pm list <linux-pm@lists.linux-foundation.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: David Chinner <david@fromorbit.com>
Cc: Lachlan McIlroy <lachlan@sgi.com>
LKML-Reference: <200912130007.30541.rjw@sisk.pl>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
      7539a3b3
  13. 11 12月, 2009 1 次提交
    • I
      sched: Remove forced2_migrations stats · b9889ed1
      由 Ingo Molnar 提交于 
      This build warning:

 kernel/sched.c: In function 'set_task_cpu':
 kernel/sched.c:2070: warning: unused variable 'old_rq'

Made me realize that the forced2_migrations stat looks pretty
pointless (and a misnomer) - remove it.

Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
LKML-Reference: <new-submission>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
      b9889ed1
  15. 10 12月, 2009 2 次提交
  17. 09 12月, 2009 11 次提交