linux-toradex.git/kernel/sched, branch v3.2-rc2-rt4

sched/rt: Fix wait_task_interactive() to test rt_spin_lock state

2012-04-13T16:01:53+00:00

The wait_task_interactive() will have a task sleep waiting for another
task to have a certain state. But it ignores the rt_spin_locks state
and can return with an incorrect result if the task it is waiting
for is blocked on a rt_spin_lock() and is waking up.

The rt_spin_locks save the tasks state in the saved_state field
and the wait_task_interactive() must also test that state.

Signed-off-by: Steven Rostedt 
Cc: Carsten Emde 
Cc: John Kacur 
Cc: Peter Zijlstra 
Cc: Clark Williams 
Cc: stable-rt@vger.kernel.org
Link: http://lkml.kernel.org/r/20120301190345.979435764@goodmis.org
Signed-off-by: Thomas Gleixner

sched-clear-pf-thread-bound-on-fallback-rq.patch

2012-04-13T16:01:38+00:00

Signed-off-by: Thomas Gleixner

sched: Have migrate_disable ignore bounded threads

2012-04-13T16:01:38+00:00

Signed-off-by: Peter Zijlstra 
Cc: Peter Zijlstra 
Cc: Clark Williams 
Link: http://lkml.kernel.org/r/20110927124423.567944215@goodmis.org
Signed-off-by: Thomas Gleixner

sched: Do not compare cpu masks in scheduler

2012-04-13T16:01:37+00:00

Signed-off-by: Peter Zijlstra 
Cc: Peter Zijlstra 
Cc: Clark Williams 
Link: http://lkml.kernel.org/r/20110927124423.128129033@goodmis.org
Signed-off-by: Thomas Gleixner

sched: Postpone actual migration disalbe to schedule

2012-04-13T16:01:37+00:00

The migrate_disable() can cause a bit of a overhead to the RT kernel,
as changing the affinity is expensive to do at every lock encountered.
As a running task can not migrate, the actual disabling of migration
does not need to occur until the task is about to schedule out.

In most cases, a task that disables migration will enable it before
it schedules making this change improve performance tremendously.

[ Frank Rowand: UP compile fix ]

Signed-off-by: Steven Rostedt 
Cc: Peter Zijlstra 
Cc: Clark Williams 
Link: http://lkml.kernel.org/r/20110927124422.779693167@goodmis.org
Signed-off-by: Thomas Gleixner

sched: teach migrate_disable about atomic contexts

2012-04-13T16:01:37+00:00

   [] spin_bug+0x94/0xa8
 [] do_raw_spin_lock+0x43/0xea
 [] _raw_spin_lock_irqsave+0x6b/0x85
 [] ? migrate_disable+0x75/0x12d
 [] ? pin_current_cpu+0x36/0xb0
 [] migrate_disable+0x75/0x12d
 [] pagefault_disable+0xe/0x1f
 [] copy_from_user_nmi+0x74/0xe6
 [] perf_callchain_user+0xf3/0x135

Now clearly we can't go around taking locks from NMI context, cure
this by short-circuiting migrate_disable() when we're in an atomic
context already.

Add some extra debugging to avoid things like:

  preempt_disable()
  migrate_disable();

  preempt_enable();
  migrate_enable();

Signed-off-by: Peter Zijlstra 
Link: http://lkml.kernel.org/r/1314967297.1301.14.camel@twins
Signed-off-by: Thomas Gleixner 
Link: http://lkml.kernel.org/n/tip-wbot4vsmwhi8vmbf83hsclk6@git.kernel.org

sched, rt: Fix migrate_enable() thinko

2012-04-13T16:01:37+00:00

Assigning mask = tsk_cpus_allowed(p) after p->migrate_disable = 0 ensures
that we won't see a mask change.. no push/pull, we stack tasks on one CPU.

Also add a couple fields to sched_debug for the next guy.

[ Build fix from Stratos Psomadakis  ]

Signed-off-by: Mike Galbraith 
Cc: Paul E. McKenney 
Cc: Peter Zijlstra 
Link: http://lkml.kernel.org/r/1314108763.6689.4.camel@marge.simson.net
Signed-off-by: Thomas Gleixner

sched: Generic migrate_disable

2012-04-13T16:01:37+00:00

Make migrate_disable() be a preempt_disable() for !rt kernels. This
allows generic code to use it but still enforces that these code
sections stay relatively small.

A preemptible migrate_disable() accessible for general use would allow
people growing arbitrary per-cpu crap instead of clean these things
up.

Signed-off-by: Peter Zijlstra 
Link: http://lkml.kernel.org/n/tip-275i87sl8e1jcamtchmehonm@git.kernel.org

sched: Optimize migrate_disable

2012-04-13T16:01:36+00:00

Change from task_rq_lock() to raw_spin_lock(&rq->lock) to avoid a few
atomic ops. See comment on why it should be safe.

Signed-off-by: Peter Zijlstra 
Link: http://lkml.kernel.org/n/tip-cbz6hkl5r5mvwtx5s3tor2y6@git.kernel.org

sched-migrate-disable.patch

2012-04-13T16:01:36+00:00

Signed-off-by: Thomas Gleixner