From: Steven Rostedt <rostedt@goodmis.org>
To: linux-kernel@vger.kernel.org,
linux-rt-users <linux-rt-users@vger.kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>,
Carsten Emde <C.Emde@osadl.org>, John Kacur <jkacur@redhat.com>,
Peter Zijlstra <peterz@infradead.org>,
Clark Williams <clark.williams@gmail.com>,
Ingo Molnar <mingo@kernel.org>,
Frank Rowand <frank.rowand@am.sony.com>,
Mike Galbraith <bitbucket@online.de>
Subject: [RFC][PATCH RT 3/4 v2] sched/rt: Initiate a pull when the priority of a task is lowered
Date: Wed, 12 Dec 2012 14:27:36 -0500 [thread overview]
Message-ID: <20121212193920.669763727@goodmis.org> (raw)
In-Reply-To: 20121212192733.221810086@goodmis.org
[-- Attachment #1: rt-migrate-redo.patch --]
[-- Type: text/plain, Size: 897 bytes --]
If a task lowers its priority (say by losing priority inheritance)
if a higher priority task is waiting on another CPU, initiate a pull.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Index: linux-rt.git/kernel/sched/rt.c
===================================================================
--- linux-rt.git.orig/kernel/sched/rt.c
+++ linux-rt.git/kernel/sched/rt.c
@@ -997,6 +997,8 @@ inc_rt_prio(struct rt_rq *rt_rq, int pri
inc_rt_prio_smp(rt_rq, prio, prev_prio);
}
+static int pull_rt_task(struct rq *this_rq);
+
static void
dec_rt_prio(struct rt_rq *rt_rq, int prio)
{
@@ -1021,6 +1023,10 @@ dec_rt_prio(struct rt_rq *rt_rq, int pri
rt_rq->highest_prio.curr = MAX_RT_PRIO;
dec_rt_prio_smp(rt_rq, prio, prev_prio);
+
+ /* Try to pull RT tasks here if we lower this rq's prio */
+ if (prev_prio < rt_rq->highest_prio.curr)
+ pull_rt_task(rq_of_rt_rq(rt_rq));
}
#else
next prev parent reply other threads:[~2012-12-12 19:27 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-12-12 19:27 [RFC][PATCH RT 0/4 v2] sched/rt: Lower rq lock contention latencies on many CPU boxes Steven Rostedt
2012-12-12 19:27 ` [RFC][PATCH RT 1/4 v2] sched/rt: Fix push_rt_task() to have the same checks as the caller did Steven Rostedt
2012-12-12 19:27 ` [RFC][PATCH RT 2/4 v2] sched/rt: Try to migrate task if preempting pinned rt task Steven Rostedt
2012-12-12 19:27 ` Steven Rostedt [this message]
2012-12-12 19:27 ` [RFC][PATCH RT 4/4 v2] sched/rt: Use IPI to trigger RT task push migration instead of pulling Steven Rostedt
2012-12-12 20:44 ` Steven Rostedt
2012-12-13 19:53 ` Steven Rostedt
2012-12-21 15:42 ` Mike Galbraith
2013-02-13 16:49 ` John Kacur
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