[PATCH v2] sched: unlikely corrupted stack end

From: WANG Chao <wcwxyz@gmail.com>
To: Ingo Molnar <mingo@redhat.com>, Peter Zijlstra <peterz@infradead.org>
Cc: linux-kernel@vger.kernel.org
Subject: [PATCH v2] sched: unlikely corrupted stack end
Date: Tue, 14 Jun 2016 16:24:23 +0800	[thread overview]
Message-ID: <20160614082423.6068-1-wcwxyz@gmail.com> (raw)
In-Reply-To: <20160614064306.48035-1-wcwxyz@gmail.com>

unlikely() was dropped in commit ce03e4137bb2 ("sched/core: Drop
unlikely behind BUG_ON()"), but commit 29d6455178a0 ("sched: panic on
corrupted stack end") dropped BUG_ON() and called panic directly.

Now we should bring unlikely() back for branch prediction. While we're
at it, it's better and cleaner to turn task_stack_end_corrupted() into
inline function.

Signed-off-by: WANG Chao <wcwxyz@gmail.com>
---
 include/linux/sched.h | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/include/linux/sched.h b/include/linux/sched.h
index 6e42ada26345..797ca1975431 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -2997,8 +2997,11 @@ static inline unsigned long *end_of_stack(struct task_struct *p)
 }
 
 #endif
-#define task_stack_end_corrupted(task) \
-		(*(end_of_stack(task)) != STACK_END_MAGIC)
+
+static inline int task_stack_end_corrupted(struct task_struct *p)
+{
+	return unlikely(*(end_of_stack(p)) != STACK_END_MAGIC);
+}
 
 static inline int object_is_on_stack(void *obj)
 {
-- 
2.8.4
