Commit ce03e413 authored Oct 05, 2015 by Geliang Tang Committed by Ingo Molnar Oct 06, 2015

sched/core: Drop unlikely behind BUG_ON()

(1) For !CONFIG_BUG cases, the bug call is a no-op, so we couldn't care
    less and the change is ok.

(2) PPC and MIPS, which HAVE_ARCH_BUG_ON, do not rely on branch predictions
    as it seems to be pointless [1] and thus callers should not be trying to
    push an optimization in the first place.

(3) For CONFIG_BUG and !HAVE_ARCH_BUG_ON cases, BUG_ON() contains an
    unlikely compiler flag already.

Hence, we can drop unlikely behind BUG_ON().

  [1] http://lkml.iu.edu/hypermail/linux/kernel/1101.3/02289.html



Signed-off-by: Geliang Tang <geliangtang@163.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Link: http://lkml.kernel.org/r/6fa7125979f98bbeac26e268271769b6ca935c8d.1444051018.git.geliangtang@163.com


Signed-off-by: Ingo Molnar <mingo@kernel.org>

parent 1de64443

kernel/sched/core.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -2971,7 +2971,7 @@ static noinline void __schedule_bug(struct task_struct *prev)
		static inline void schedule_debug(struct task_struct *prev)
		{
		#ifdef CONFIG_SCHED_STACK_END_CHECK
		BUG_ON(unlikely(task_stack_end_corrupted(prev)));
		BUG_ON(task_stack_end_corrupted(prev));
		#endif

		if (unlikely(in_atomic_preempt_off())) {

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