From: Peter Zijlstra <peterz@infradead.org>
To: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Cc: linux-kernel@vger.kernel.org, stable@kernel.org,
Ingo Molnar <mingo@elte.hu>
Subject: Re: [PATCH] posixtimers: Fix posix clock monotonicity v2
Date: Wed, 18 Mar 2009 11:58:07 +0100 [thread overview]
Message-ID: <1237373887.5069.203.camel@laptop> (raw)
In-Reply-To: <49C0CFC2.7080604@jp.fujitsu.com>
On Wed, 2009-03-18 at 19:41 +0900, Hidetoshi Seto wrote:
> Impact: Regression fix (against clock_gettime() backwarding bug)
>
> This patch re-introduces a couple of function, task_sched_runtime
> and thread_group_sched_runtime, which was once removed at the
> time of 2.6.28-rc1.
>
> These functions protect the sampling of thread/process clock with
> rq lock. This rq lock is required not to update rq->clock durling
> the sampling.
> i.e.
> The clock_gettime() may return
> ((accounted runtime before update) + (delta after update))
> that is less than what it should be.
>
> v1 -> v2:
> - Revises comments for functions and patch description.
> - Add note about accuracy of thread group's runtime.
>
> Signed-off-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
> Cc: Peter Zijlstra <peterz@infradead.org>
> Cc: Ingo Molnar <mingo@elte.hu>
> Cc: stable@kernel.org [2.6.28.x]
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Thanks Hidetoshi-san.
next prev parent reply other threads:[~2009-03-18 10:58 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-03-17 6:13 [PATCH] posixtimers: Fix posix clock monotonicity Hidetoshi Seto
2009-03-17 6:16 ` KAMEZAWA Hiroyuki
2009-03-17 6:31 ` Hidetoshi Seto
2009-03-18 10:41 ` [PATCH] posixtimers: Fix posix clock monotonicity v2 Hidetoshi Seto
2009-03-18 10:58 ` Peter Zijlstra [this message]
2009-03-18 11:34 ` Ingo Molnar
2009-03-23 5:07 ` Hidetoshi Seto
2009-03-23 5:11 ` [PATCH 1/2] x86: Rename __task_delta_exec() to task_delta_exec_locked() Hidetoshi Seto
2009-03-23 7:57 ` Peter Zijlstra
2009-03-23 9:13 ` Hidetoshi Seto
2009-03-23 9:40 ` [PATCH] posixtimers: Fix posix clock monotonicity v3 Hidetoshi Seto
2009-03-23 9:42 ` Peter Zijlstra
2009-03-23 5:13 ` [PATCH 2/2] posixtimers: Fix posix clock monotonicity v2 Hidetoshi Seto
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