From: Peter Zijlstra <peterz@infradead.org>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: linux-kernel@vger.kernel.org, Ingo Molnar <mingo@elte.hu>,
Andrew Morton <akpm@linux-foundation.org>,
Thomas Gleixner <tglx@linutronix.de>,
Gregory Haskins <gregory.haskins@gmail.com>,
Steven Rostedt <srostedt@redhat.com>
Subject: Re: [PATCH 1/2] sched: check for pushing rt tasks after all scheduling
Date: Wed, 29 Jul 2009 10:41:24 +0200 [thread overview]
Message-ID: <1248856884.6987.3043.camel@twins> (raw)
In-Reply-To: <20090729042526.205923666@goodmis.org>
On Wed, 2009-07-29 at 00:21 -0400, Steven Rostedt wrote:
> plain text document attachment
> (0001-sched-check-for-pushing-rt-tasks-after-all-schedulin.patch)
> From: Steven Rostedt <srostedt@redhat.com>
>
> The current method for pushing RT tasks after scheduling only
> happens after a context switch. But we found cases where a task
> is set up on a run queue to be pushed but the push never happens
> because the schedule chooses the same task.
>
> This bug was found with the help of Gregory Haskins and the use of
> ftrace (trace_printk). It tooks several days for both of us analyzing
> the code and the trace output to find this.
> + if (current->sched_class->needs_post_schedule)
> + post_schedule = current->sched_class->needs_post_schedule(rq);
> + if (post_schedule)
> + current->sched_class->post_schedule(rq);
Why can't we omit that first call, and do the second unconditionally,
using storage in the class rq to save state?
next prev parent reply other threads:[~2009-07-29 8:38 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-07-29 4:21 [PATCH 0/2] [GIT PULL] sched: fixes for rt-migration-test failures Steven Rostedt
2009-07-29 4:21 ` [PATCH 1/2] sched: check for pushing rt tasks after all scheduling Steven Rostedt
2009-07-29 8:41 ` Peter Zijlstra [this message]
2009-07-29 13:14 ` Gregory Haskins
2009-07-29 15:08 ` [PATCH] sched: enhance the pre/post scheduling logic Gregory Haskins
2009-07-30 7:36 ` Peter Zijlstra
2009-08-02 13:13 ` [tip:sched/core] sched: Enhance " tip-bot for Gregory Haskins
2009-08-02 13:12 ` [tip:sched/core] sched: Check for pushing rt tasks after all scheduling tip-bot for Steven Rostedt
2009-07-29 4:21 ` [PATCH 2/2] sched: add new prio to cpupri before removing old prio Steven Rostedt
2009-08-02 13:13 ` [tip:sched/core] sched: Add " tip-bot for Steven Rostedt
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