[tip:sched/core] sched/core: Simplify INIT_PREEMPT_COUNT

[tip-bot for Peter Zijlstra]

Commit-ID:  aed586c2f11e5cddd52c180ccde651d0d35b736b
Gitweb:     http://git.kernel.org/tip/aed586c2f11e5cddd52c180ccde651d0d35b736b
Author:     Peter Zijlstra <peterz@xxxxxxxxxxxxx>
AuthorDate: Tue, 29 Sep 2015 11:28:26 +0200
Committer:  Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Tue, 29 Sep 2015 12:27:39 +0200

sched/core: Simplify INIT_PREEMPT_COUNT

As per commit d86ee4809d03 ("sched: optimize cond_resched()") we
need PREEMPT_ACTIVE to avoid cond_resched() from working before
the scheduler is setup.

However, keeping preemption disabled should do the same thing
already, making the PREEMPT_ACTIVE part entirely redundant.

Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Mike Galbraith <efault@xxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: fweisbec@xxxxxxxxx
Cc: linux-kernel@xxxxxxxxxxxxxxx
Cc: oleg@xxxxxxxxxx
Cc: rostedt@xxxxxxxxxxx
Cc: umgwanakikbuti@xxxxxxxxx
Link: http://lkml.kernel.org/r/20150929093519.706413197@xxxxxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
 include/linux/sched.h | 7 ++-----
 1 file changed, 2 insertions(+), 5 deletions(-)

diff --git a/include/linux/sched.h b/include/linux/sched.h
index 699228b..5ef9e2c 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -608,17 +608,14 @@ struct task_cputime_atomic {
 /*
  * Disable preemption until the scheduler is running.
  * Reset by start_kernel()->sched_init()->init_idle().
- *
- * We include PREEMPT_ACTIVE to avoid cond_resched() from working
- * before the scheduler is active -- see should_resched().
  */
-#define INIT_PREEMPT_COUNT	(PREEMPT_DISABLED + PREEMPT_ACTIVE)
+#define INIT_PREEMPT_COUNT	PREEMPT_DISABLED
 
 /**
  * struct thread_group_cputimer - thread group interval timer counts
  * @cputime_atomic:	atomic thread group interval timers.
  * @running:		non-zero when there are timers running and
- * 			@cputime receives updates.
+ *			@cputime receives updates.
  *
  * This structure contains the version of task_cputime, above, that is
  * used for thread group CPU timer calculations.
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