linux.git/kernel/sched_idletask.c, branch master

sched: Move all scheduler bits into kernel/sched/

2011-11-17T11:20:22+00:00

There's too many sched*.[ch] files in kernel/, give them their own
directory.

(No code changed, other than Makefile glue added.)

Signed-off-by: Peter Zijlstra 
Signed-off-by: Ingo Molnar

sched: Make separate sched*.c translation units

2011-11-17T11:20:19+00:00

Since once needs to do something at conferences and fixing compile
warnings doesn't actually require much if any attention I decided
to break up the sched.c #include "*.c" fest.

This further modularizes the scheduler code.

Signed-off-by: Peter Zijlstra 
Link: http://lkml.kernel.org/n/tip-x0fcd3mnp8f9c99grcpewmhi@git.kernel.org
Signed-off-by: Ingo Molnar

sched: Drop the rq argument to sched_class::select_task_rq()

2011-04-14T06:52:36+00:00

In preparation of calling select_task_rq() without rq->lock held, drop
the dependency on the rq argument.

Reviewed-by: Frank Rowand 
Signed-off-by: Peter Zijlstra 
Cc: Mike Galbraith 
Cc: Nick Piggin 
Cc: Linus Torvalds 
Cc: Andrew Morton 
Link: http://lkml.kernel.org/r/20110405152729.031077745@chello.nl
Signed-off-by: Ingo Molnar

sched, doc: Update sched-design-CFS.txt

2011-03-23T13:09:41+00:00

Correct ->dequeue_tree() thinko into sched_class->dequeue_task
and drop all references to ->task_new() since it is obviously
gone.

Signed-off-by: Borislav Petkov 
Cc: Peter Zijlstra 
Cc: Mike Galbraith 
LKML-Reference: <1300815978-16618-1-git-send-email-bp@amd64.org>
Signed-off-by: Ingo Molnar

sched: Fix switch_from_fair()

2011-01-26T11:33:22+00:00

When a task is taken out of the fair class we must ensure the vruntime
is properly normalized because when we put it back in it will assume
to be normalized.

The case that goes wrong is when changing away from the fair class
while sleeping. Sleeping tasks have non-normalized vruntime in order
to make sleeper-fairness work. So treat the switch away from fair as a
wakeup and preserve the relative vruntime.

Also update sysrq-n to call the ->switch_{to,from} methods.

Reported-by: Onkalo Samu 
Signed-off-by: Peter Zijlstra 
LKML-Reference: 
Signed-off-by: Ingo Molnar

sched: Simplify the idle scheduling class

2011-01-26T11:33:22+00:00

Since commit 48c5ccae88dcd (sched: Simplify cpu-hot-unplug task
migration) this should no longer happen, so remove the code.

Signed-off-by: Peter Zijlstra 
LKML-Reference: 
Signed-off-by: Ingo Molnar

sched: Cure load average vs NO_HZ woes

2010-04-23T09:02:02+00:00

Chase reported that due to us decrementing calc_load_task prematurely
(before the next LOAD_FREQ sample), the load average could be scewed
by as much as the number of CPUs in the machine.

This patch, based on Chase's patch, cures the problem by keeping the
delta of the CPU going into NO_HZ idle separately and folding that in
on the next LOAD_FREQ update.

This restores the balance and we get strict LOAD_FREQ period samples.

Signed-off-by: Peter Zijlstra 
Acked-by: Chase Douglas 
LKML-Reference: <1271934490.1776.343.camel@laptop>
Signed-off-by: Ingo Molnar

sched: Add enqueue/dequeue flags

2010-04-02T18:12:05+00:00

In order to reduce the dependency on TASK_WAKING rework the enqueue
interface to support a proper flags field.

Replace the int wakeup, bool head arguments with an int flags argument
and create the following flags:

  ENQUEUE_WAKEUP - the enqueue is a wakeup of a sleeping task,
  ENQUEUE_WAKING - the enqueue has relative vruntime due to
                   having sched_class::task_waking() called,
  ENQUEUE_HEAD - the waking task should be places on the head
                 of the priority queue (where appropriate).

For symmetry also convert sched_class::dequeue() to a flags scheme.

Signed-off-by: Peter Zijlstra 
LKML-Reference: 
Signed-off-by: Ingo Molnar

sched: Fix TASK_WAKING vs fork deadlock

2010-04-02T18:12:03+00:00

Oleg noticed a few races with the TASK_WAKING usage on fork.

 - since TASK_WAKING is basically a spinlock, it should be IRQ safe
 - since we set TASK_WAKING (*) without holding rq->lock it could
   be there still is a rq->lock holder, thereby not actually
   providing full serialization.

(*) in fact we clear PF_STARTING, which in effect enables TASK_WAKING.

Cure the second issue by not setting TASK_WAKING in sched_fork(), but
only temporarily in wake_up_new_task() while calling select_task_rq().

Cure the first by holding rq->lock around the select_task_rq() call,
this will disable IRQs, this however requires that we push down the
rq->lock release into select_task_rq_fair()'s cgroup stuff.

Because select_task_rq_fair() still needs to drop the rq->lock we
cannot fully get rid of TASK_WAKING.

Reported-by: Oleg Nesterov 
Signed-off-by: Peter Zijlstra 
LKML-Reference: 
Signed-off-by: Ingo Molnar

sched: Remove the sched_class load_balance methods

2010-01-21T12:40:09+00:00

Take out the sched_class methods for load-balancing.

Signed-off-by: Peter Zijlstra 
LKML-Reference: 
Signed-off-by: Ingo Molnar