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From: Greg KH <gregkh@suse.de>
To: linux-kernel@vger.kernel.org, stable@kernel.org
Cc: stable-review@kernel.org, torvalds@linux-foundation.org,
	akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk,
	Lennart Poettering <lennart@poettering.net>,
	Linus Walleij <linus.walleij@stericsson.com>,
	Peter Zijlstra <a.p.zijlstra@chello.nl>,
	Ingo Molnar <mingo@elte.hu>
Subject: [08/82] sched: Drop all load weight manipulation for RT tasks
Date: Fri, 19 Nov 2010 13:55:29 -0800	[thread overview]
Message-ID: <20101119215639.401285027@clark.site> (raw)
In-Reply-To: <20101119215658.GA7804@kroah.com

2.6.35-stable review patch.  If anyone has any objections, please let us know.

------------------

From: Linus Walleij <linus.walleij@stericsson.com>

commit 17bdcf949d03306b308c5fb694849cd35f119807 upstream.

Load weights are for the CFS, they do not belong in the RT task. This makes all
RT scheduling classes leave the CFS weights alone.

This fixes a real bug as well: I noticed the following phonomena: a process
elevated to SCHED_RR forks with SCHED_RESET_ON_FORK set, and the child is
indeed SCHED_OTHER, and the niceval is indeed reset to 0. However the weight
inserted by set_load_weight() remains at 0, giving the task insignificat
priority.

With this fix, the weight is reset to what the task had before being elevated
to SCHED_RR/SCHED_FIFO.

Cc: Lennart Poettering <lennart@poettering.net>
Signed-off-by: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <1286807811-10568-1-git-send-email-linus.walleij@stericsson.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
 kernel/sched.c |    6 ------
 1 file changed, 6 deletions(-)

--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -1830,12 +1830,6 @@ static void dec_nr_running(struct rq *rq
 
 static void set_load_weight(struct task_struct *p)
 {
-	if (task_has_rt_policy(p)) {
-		p->se.load.weight = 0;
-		p->se.load.inv_weight = WMULT_CONST;
-		return;
-	}
-
 	/*
 	 * SCHED_IDLE tasks get minimal weight:
 	 */



                 reply	other threads:[~2010-11-19 22:34 UTC|newest]

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