From: Peter Zijlstra <a.p.zijlstra@chello.nl>
To: Mel Gorman <mgorman@suse.de>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Miao Xie <miaox@cn.fujitsu.com>, Christoph Lameter <cl@linux.com>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] cpuset: mm: Remove memory barrier damage from the page allocator
Date: Fri, 02 Mar 2012 22:21:02 +0100 [thread overview]
Message-ID: <1330723262.11248.233.camel@twins> (raw)
In-Reply-To: <20120302112358.GA3481@suse.de>
On Fri, 2012-03-02 at 11:23 +0000, Mel Gorman wrote:
> For extra style points, the commit introduced the use of yield() in an
> implementation of what looks like a spinning mutex.
Andrew, could you simply say no to any patch adding a yield()? There's a
99% chance its a bug, as was this.
This code would life-lock when cpuset_change_task_nodemask() would be
called by the highest priority FIFO task on UP or when pinned to the
same cpu the task doing get_mems_allowed().
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WARNING: multiple messages have this Message-ID (diff)
From: Peter Zijlstra <a.p.zijlstra@chello.nl>
To: Mel Gorman <mgorman@suse.de>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Miao Xie <miaox@cn.fujitsu.com>, Christoph Lameter <cl@linux.com>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] cpuset: mm: Remove memory barrier damage from the page allocator
Date: Fri, 02 Mar 2012 22:21:02 +0100 [thread overview]
Message-ID: <1330723262.11248.233.camel@twins> (raw)
In-Reply-To: <20120302112358.GA3481@suse.de>
On Fri, 2012-03-02 at 11:23 +0000, Mel Gorman wrote:
> For extra style points, the commit introduced the use of yield() in an
> implementation of what looks like a spinning mutex.
Andrew, could you simply say no to any patch adding a yield()? There's a
99% chance its a bug, as was this.
This code would life-lock when cpuset_change_task_nodemask() would be
called by the highest priority FIFO task on UP or when pinned to the
same cpu the task doing get_mems_allowed().
next prev parent reply other threads:[~2012-03-02 21:21 UTC|newest]
Thread overview: 44+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-03-02 11:23 [PATCH] cpuset: mm: Remove memory barrier damage from the page allocator Mel Gorman
2012-03-02 11:23 ` Mel Gorman
2012-03-02 16:19 ` Christoph Lameter
2012-03-02 16:19 ` Christoph Lameter
2012-03-02 17:43 ` Mel Gorman
2012-03-02 17:43 ` Mel Gorman
2012-03-02 19:53 ` Christoph Lameter
2012-03-02 19:53 ` Christoph Lameter
2012-03-02 21:25 ` Peter Zijlstra
2012-03-02 21:25 ` Peter Zijlstra
2012-03-02 23:47 ` David Rientjes
2012-03-02 23:47 ` David Rientjes
2012-03-05 9:44 ` Mel Gorman
2012-03-05 9:44 ` Mel Gorman
2012-03-06 23:31 ` David Rientjes
2012-03-06 23:31 ` David Rientjes
2012-03-05 9:35 ` Mel Gorman
2012-03-05 9:35 ` Mel Gorman
2012-03-02 21:21 ` Peter Zijlstra [this message]
2012-03-02 21:21 ` Peter Zijlstra
2012-03-05 20:18 ` Andrew Morton
2012-03-05 20:18 ` Andrew Morton
2012-03-06 2:01 ` [RFC PATCH] checkpatch: Warn on use of yield() Joe Perches
2012-03-06 2:01 ` Joe Perches
2012-03-06 12:45 ` Peter Zijlstra
2012-03-06 12:45 ` Peter Zijlstra
2012-03-06 13:14 ` Glauber Costa
2012-03-06 13:14 ` Glauber Costa
2012-03-06 13:25 ` Peter Zijlstra
2012-03-06 13:25 ` Peter Zijlstra
2012-03-06 13:27 ` Glauber Costa
2012-03-06 13:27 ` Glauber Costa
2012-03-06 17:41 ` Joe Perches
2012-03-06 17:41 ` Joe Perches
2012-03-06 17:54 ` Peter Zijlstra
2012-03-06 17:54 ` Peter Zijlstra
2012-03-06 18:00 ` Joe Perches
2012-03-06 18:00 ` Joe Perches
2012-03-06 18:17 ` Joe Perches
2012-03-06 18:17 ` Joe Perches
2012-03-06 19:31 ` [PATCH 1/2] " Joe Perches
2012-03-06 19:31 ` [PATCH 2/2] checkpatch: whitespace - add/remove blank lines Joe Perches
2012-03-08 15:56 ` [PATCH 1/2 V2] checkpatch: Warn on use of yield() Joe Perches
2012-03-13 4:47 ` [tip:sched/core] sched: Update yield() docs tip-bot for Peter Zijlstra
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