[RFC][PATCH 01/11] sched: Simplify INIT_PREEMPT_COUNT

From	Peter Zijlstra <peterz@infradead.org>
Newsgroups	linux.kernel
Subject	[RFC][PATCH 01/11] sched: Simplify INIT_PREEMPT_COUNT
Date	2015-09-29 11:50 +0200
Message-ID	<qdZHQ-2IS-15@gated-at.bofh.it> (permalink)
References	<qdZHQ-2IS-3@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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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@infradead.org>
---
 include/linux/sched.h |    7 ++-----
 1 file changed, 2 insertions(+), 5 deletions(-)

--- 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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[RFC][PATCH 01/11] sched: Simplify INIT_PREEMPT_COUNT Peter Zijlstra <peterz@infradead.org> - 2015-09-29 11:50 +0200
  [tip:sched/core] sched/core: Simplify INIT_PREEMPT_COUNT tip-bot for Peter Zijlstra <tipbot@zytor.com> - 2015-09-29 12:40 +0200
  Re: [RFC][PATCH 01/11] sched: Simplify INIT_PREEMPT_COUNT Frederic Weisbecker <fweisbec@gmail.com> - 2015-09-29 15:30 +0200
  Re: [RFC][PATCH 01/11] sched: Simplify INIT_PREEMPT_COUNT Steven Rostedt <rostedt@goodmis.org> - 2015-09-29 16:50 +0200
    Re: [RFC][PATCH 01/11] sched: Simplify INIT_PREEMPT_COUNT Peter Zijlstra <peterz@infradead.org> - 2015-09-29 17:00 +0200
  Re: [RFC][PATCH 01/11] sched: Simplify INIT_PREEMPT_COUNT Steven Rostedt <rostedt@goodmis.org> - 2015-09-29 17:10 +0200
    Re: [RFC][PATCH 01/11] sched: Simplify INIT_PREEMPT_COUNT Peter Zijlstra <peterz@infradead.org> - 2015-09-29 17:20 +0200

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