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From: Konstantin Khlebnikov <khlebnikov@openvz.org>
To: Oleg Nesterov <oleg@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
	Hugh Dickins <hughd@google.com>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"linux-mm@kvack.org" <linux-mm@kvack.org>,
	Markus Trippelsdorf <markus@trippelsdorf.de>,
	KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Subject: Re: [PATCH v2] mm: correctly synchronize rss-counters at exit/exec
Date: Wed, 11 Apr 2012 00:09:14 +0400	[thread overview]
Message-ID: <4F84936A.1060708@openvz.org> (raw)
In-Reply-To: <20120410191059.GA5678@redhat.com>

Oleg Nesterov wrote:
> On 04/10, Konstantin Khlebnikov wrote:
>>
>> This patch moves sync_mm_rss() into mm_release(), and moves mm_release() out of
>> do_exit() and calls it earlier. After mm_release() there should be no page-faults.
>
> Can't prove, but I feel there should be a simpler fix...
>
> Anyway, this patch is not exactly correct.
>
>> @@ -959,9 +959,10 @@ void do_exit(long code)
>>   				preempt_count());
>>
>>   	acct_update_integrals(tsk);
>> -	/* sync mm's RSS info before statistics gathering */
>> -	if (tsk->mm)
>> -		sync_mm_rss(tsk->mm);
>> +
>> +	/* Release mm and sync mm's RSS info before statistics gathering */
>> +	mm_release(tsk, tsk->mm);
>
> This breaks kthread_stop() at least.
>
> The exiting kthread shouldn't do complete_vfork_done() until it
> sets ->exit_code.

Ouch, I was afraid something like that.

>
> Oleg.
>

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  reply	other threads:[~2012-04-10 20:09 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-04-09 20:03 [PATCH] mm: sync rss-counters at the end of exit_mm() Konstantin Khlebnikov
2012-04-09 21:04 ` KOSAKI Motohiro
2012-04-09 22:03   ` Hugh Dickins
2012-04-10  0:33     ` KAMEZAWA Hiroyuki
2012-04-10  6:34     ` Konstantin Khlebnikov
2012-04-10 16:04       ` Markus Trippelsdorf
2012-04-10  0:35 ` KAMEZAWA Hiroyuki
2012-04-10  5:43   ` Konstantin Khlebnikov
2012-04-10 17:07 ` [PATCH v2] mm: correctly synchronize rss-counters at exit/exec Konstantin Khlebnikov
2012-04-10 18:43   ` Andrew Morton
2012-04-10 19:52     ` Konstantin Khlebnikov
2012-04-10 19:10   ` Oleg Nesterov
2012-04-10 20:09     ` Konstantin Khlebnikov [this message]
2012-04-12  8:09 ` [PATCH 1/2] mm: set task exit code before complete_vfork_done() Konstantin Khlebnikov
2012-04-12 23:35   ` Andrew Morton
2012-04-12 23:54   ` Oleg Nesterov
2012-04-20 17:59     ` Oleg Nesterov
2012-04-20 19:23       ` Konstantin Khlebnikov
2012-04-20 20:41         ` Oleg Nesterov
2012-04-25 20:01           ` Andrew Morton
2012-04-12  8:09 ` [PATCH 2/2] mm: call complete_vfork_done() after clearing child_tid and flushing rss-counters Konstantin Khlebnikov
2012-04-12 23:39   ` Andrew Morton
2012-04-13  6:43     ` Konstantin Khlebnikov

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