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From: Andi Kleen <andi@firstfloor.org>
To: linux-kernel@vger.kernel.org
Cc: x86@kernel.org, peterz@infradead.org, akpm@linux-foundation.org,
	Andi Kleen <ak@linux.intel.com>
Subject: [PATCH 6/6] sched: Inline the need_resched test into the caller for _cond_resched
Date: Fri, 16 Aug 2013 14:17:24 -0700
Message-ID: <1376687844-19857-7-git-send-email-andi@firstfloor.org> (raw)
In-Reply-To: <1376687844-19857-1-git-send-email-andi@firstfloor.org>

From: Andi Kleen <ak@linux.intel.com>

_cond_resched does at least two explicit calls just to decide to do
nothing: _cond_resched and should_resched(). Inline a need_resched()
into the caller to avoid these calls in the common case of no reschedule
being needed.

Signed-off-by: Andi Kleen <ak@linux.intel.com>
---
 include/linux/sched.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/linux/sched.h b/include/linux/sched.h
index 97f4b78..dd3fafc 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -2435,7 +2435,7 @@ extern int __cond_resched_softirq(void);
 
 #ifdef CONFIG_PREEMPT_VOLUNTARY
 extern int _cond_resched(void);
-# define might_resched() _cond_resched()
+# define might_resched() (need_resched() ? _cond_resched() : 0)
 #else
 # define might_resched() do { } while (0)
 #endif
-- 
1.8.3.1


  parent reply index

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-08-16 21:17 Improve preempt-scheduling and x86 user access v3 Andi Kleen
2013-08-16 21:17 ` [PATCH 1/6] x86: Add 1/2/4/8 byte optimization to 64bit __copy_{from,to}_user_inatomic Andi Kleen
2013-09-10 23:30   ` [tip:x86/uaccess] x86: Add 1/2/4/ 8 " tip-bot for Andi Kleen
2013-08-16 21:17 ` [PATCH 2/6] x86: Include linux/sched.h in asm/uaccess.h Andi Kleen
2013-08-16 21:17 ` [PATCH 3/6] tree-sweep: Include linux/sched.h for might_sleep users Andi Kleen
2013-08-31 18:22   ` Geert Uytterhoeven
2013-09-10 23:52     ` Andrew Morton
2013-09-11  4:51       ` Andi Kleen
2013-09-11  5:36         ` Ingo Molnar
2013-08-16 21:17 ` [PATCH 4/6] Move might_sleep and friends from kernel.h to sched.h Andi Kleen
2013-08-27 23:50   ` Andrew Morton
2013-08-16 21:17 ` [PATCH 5/6] sched: mark should_resched() __always_inline Andi Kleen
2013-08-16 21:17 ` Andi Kleen [this message]
2013-08-28  9:29 ` Improve preempt-scheduling and x86 user access v3 Ingo Molnar

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