linux-kernel - [tip:sched/core] sched: Allow SCHED_BATCH to preempt SCHED

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <tip-a2f5c9ab79f78e8b91ac993e0543d65b661dd19b@git.kernel.org>
Date:	Fri, 4 Mar 2011 11:49:24 GMT
From:	tip-bot for Darren Hart <dvhart@...ux.intel.com>
To:	linux-tip-commits@...r.kernel.org
Cc:	linux-kernel@...r.kernel.org, hpa@...or.com, mingo@...hat.com,
	a.p.zijlstra@...llo.nl, dvhart@...ux.intel.com, efault@....de,
	richard.purdie@...uxfoundation.org, tglx@...utronix.de,
	mingo@...e.hu
Subject: [tip:sched/core] sched: Allow SCHED_BATCH to preempt SCHED_IDLE tasks

Commit-ID:  a2f5c9ab79f78e8b91ac993e0543d65b661dd19b
Gitweb:     http://git.kernel.org/tip/a2f5c9ab79f78e8b91ac993e0543d65b661dd19b
Author:     Darren Hart <dvhart@...ux.intel.com>
AuthorDate: Tue, 22 Feb 2011 13:04:33 -0800
Committer:  Ingo Molnar <mingo@...e.hu>
CommitDate: Fri, 4 Mar 2011 11:14:29 +0100

sched: Allow SCHED_BATCH to preempt SCHED_IDLE tasks

Perform the test for SCHED_IDLE before testing for SCHED_BATCH (and
ensure idle tasks don't preempt idle tasks) so the non-interactive,
but still important, SCHED_BATCH tasks will run in favor of the very
low priority SCHED_IDLE tasks.

Signed-off-by: Darren Hart <dvhart@...ux.intel.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@...llo.nl>
Acked-by: Mike Galbraith <efault@....de>
Cc: Richard Purdie <richard.purdie@...uxfoundation.org>
LKML-Reference: <1298408674-3130-2-git-send-email-dvhart@...ux.intel.com>
Signed-off-by: Ingo Molnar <mingo@...e.hu>
---
 kernel/sched_fair.c |   12 +++++++-----
 1 files changed, 7 insertions(+), 5 deletions(-)

diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c
index 3a88dee..1438e13 100644
--- a/kernel/sched_fair.c
+++ b/kernel/sched_fair.c
@@ -1870,16 +1870,18 @@ static void check_preempt_wakeup(struct rq *rq, struct task_struct *p, int wake_
 	if (test_tsk_need_resched(curr))
 		return;
 
+	/* Idle tasks are by definition preempted by non-idle tasks. */
+	if (unlikely(curr->policy == SCHED_IDLE) &&
+	    likely(p->policy != SCHED_IDLE))
+		goto preempt;
+
 	/*
-	 * Batch and idle tasks do not preempt (their preemption is driven by
-	 * the tick):
+	 * Batch and idle tasks do not preempt non-idle tasks (their preemption
+	 * is driven by the tick):
 	 */
 	if (unlikely(p->policy != SCHED_NORMAL))
 		return;
 
-	/* Idle tasks are by definition preempted by everybody. */
-	if (unlikely(curr->policy == SCHED_IDLE))
-		goto preempt;
 
 	if (!sched_feat(WAKEUP_PREEMPT))
 		return;
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/