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From: Steven Rostedt <rostedt@goodmis.org>
To: linux-kernel@vger.kernel.org
Cc: Ingo Molnar <mingo@elte.hu>,
	Andrew Morton <akpm@linux-foundation.org>,
	Peter Zijlstra <a.p.zijlstra@chello.nl>,
	Gregory Haskins <ghaskins@novell.com>
Subject: [RFC][PATCH 01/10] sched: Change rt_task(prev) in pre_schedule_rt to likely
Date: Mon, 06 Dec 2010 20:58:35 -0500	[thread overview]
Message-ID: <20101207021328.207196531@goodmis.org> (raw)
In-Reply-To: 20101207015834.196176991@goodmis.org

[-- Attachment #1: 0001-sched-Change-rt_task-prev-in-pre_schedule_rt-to-like.patch --]
[-- Type: text/plain, Size: 1048 bytes --]

From: Steven Rostedt <srostedt@redhat.com>

As found with the branch annotation profiler, the unlikely(rt_task(prev))
in pre_schedule_rt() is always wrong. In fact it should be likely due to
the fact that we got to this function because we used prev's scheduling
class (which had to be rt).

Change the unlikely(rt_task(prev)) to likely(rt_task(prev))

Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Gregory Haskins <ghaskins@novell.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 kernel/sched_rt.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/kernel/sched_rt.c b/kernel/sched_rt.c
index bea7d79..7a5c4db 100644
--- a/kernel/sched_rt.c
+++ b/kernel/sched_rt.c
@@ -1474,7 +1474,7 @@ skip:
 static void pre_schedule_rt(struct rq *rq, struct task_struct *prev)
 {
 	/* Try to pull RT tasks here if we lower this rq's prio */
-	if (unlikely(rt_task(prev)) && rq->rt.highest_prio.curr > prev->prio)
+	if (likely(rt_task(prev)) && rq->rt.highest_prio.curr > prev->prio)
 		pull_rt_task(rq);
 }
 
-- 
1.7.2.3



  reply	other threads:[~2010-12-07  2:15 UTC|newest]

Thread overview: 31+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-12-07  1:58 [RFC][PATCH 00/10] incorrect unlikely() and likely() cleanups Steven Rostedt
2010-12-07  1:58 ` Steven Rostedt [this message]
2010-12-07  3:25   ` [RFC][PATCH 01/10] sched: Change rt_task(prev) in pre_schedule_rt to likely Yong Zhang
2010-12-07  3:32     ` Steven Rostedt
2010-12-07  1:58 ` [RFC][PATCH 02/10] mm: Remove likely() from mapping_unevictable() Steven Rostedt
2010-12-07  2:22   ` Steven Rostedt
2010-12-07  7:02     ` Nick Piggin
2010-12-07 13:06       ` Steven Rostedt
2010-12-07 16:26     ` Rik van Riel
2010-12-10  7:00     ` KOSAKI Motohiro
2010-12-10  7:06       ` Joe Perches
2010-12-10  8:08         ` Miles Bader
2010-12-11  0:09           ` Steven Rostedt
2010-12-07  1:58 ` [RFC][PATCH 03/10] workqueue: It is likely that WORKER_NOT_RUNNING is true Steven Rostedt
2010-12-07  9:49   ` Tejun Heo
2010-12-07 13:07     ` Steven Rostedt
2010-12-11  0:08     ` Steven Rostedt
2010-12-11  0:09       ` Tejun Heo
2010-12-11  0:12         ` Steven Rostedt
2010-12-07  1:58 ` [RFC][PATCH 04/10] sched: Change pick_next_task_rt from unlikely to likely Steven Rostedt
2010-12-07  2:46   ` Gregory Haskins
2010-12-07  2:59     ` Steven Rostedt
2010-12-11  0:07     ` Steven Rostedt
2010-12-07  1:58 ` [RFC][PATCH 05/10] mm: Remove likely() from grab_cache_page_write_begin() Steven Rostedt
2010-12-07  2:24   ` Steven Rostedt
2010-12-07  6:56     ` Nick Piggin
2010-12-07  1:58 ` [RFC][PATCH 06/10] sched: Remove unlikely() from rt_policy() in sched.c Steven Rostedt
2010-12-07  1:58 ` [RFC][PATCH 07/10] x86: Remove unlikey()s from sched_switch segment tests Steven Rostedt
2010-12-07  1:58 ` [RFC][PATCH 08/10] fs: Remove unlikely() from fput_light() Steven Rostedt
2010-12-07  1:58 ` [RFC][PATCH 09/10] fs: Remove unlikely() from fget_light() Steven Rostedt
2010-12-07  1:58 ` [RFC][PATCH 10/10] sched: Remove unlikely() from ttwu_post_activation Steven Rostedt

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