From: tip-bot for Geliang Tang <tipbot@zytor.com>
To: linux-tip-commits@vger.kernel.org
Cc: efault@gmx.de, peterz@infradead.org, hpa@zytor.com,
linux-kernel@vger.kernel.org, torvalds@linux-foundation.org,
geliangtang@163.com, mingo@kernel.org, tglx@linutronix.de
Subject: [tip:sched/core] sched/core: Drop unlikely behind BUG_ON()
Date: Tue, 6 Oct 2015 09:17:45 -0700 [thread overview]
Message-ID: <tip-ce03e4137bb22fc560ad7a07cf4138ae2cd59f65@git.kernel.org> (raw)
In-Reply-To: <6fa7125979f98bbeac26e268271769b6ca935c8d.1444051018.git.geliangtang@163.com>
Commit-ID: ce03e4137bb22fc560ad7a07cf4138ae2cd59f65
Gitweb: http://git.kernel.org/tip/ce03e4137bb22fc560ad7a07cf4138ae2cd59f65
Author: Geliang Tang <geliangtang@163.com>
AuthorDate: Mon, 5 Oct 2015 21:26:05 +0800
Committer: Ingo Molnar <mingo@kernel.org>
CommitDate: Tue, 6 Oct 2015 17:08:22 +0200
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>
---
kernel/sched/core.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index fb14a01..a395db1 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -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())) {
prev parent reply other threads:[~2015-10-06 16:18 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-10-05 13:26 [PATCH v2 1/3] scsi: drop unlikely behind BUG_ON() Geliang Tang
2015-10-05 13:26 ` [PATCH v2 2/3] sched/core: " Geliang Tang
2015-10-05 13:26 ` [PATCH v2 3/3] mm/nommu: " Geliang Tang
2015-10-06 16:17 ` tip-bot for Geliang Tang [this message]
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