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From: Minchan Kim <minchan@kernel.org>
To: KOSAKI Motohiro <kosaki.motohiro@gmail.com>
Cc: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
	Aaditya Kumar <aaditya.kumar.30@gmail.com>,
	Mel Gorman <mel@csn.ul.ie>,
	"linux-mm@kvack.org" <linux-mm@kvack.org>,
	LKML <linux-kernel@vger.kernel.org>
Subject: Re: Accounting problem of MIGRATE_ISOLATED freed page
Date: Mon, 25 Jun 2012 10:19:41 +0900	[thread overview]
Message-ID: <4FE7BCAD.4090002@kernel.org> (raw)
In-Reply-To: <4FE530F7.1060108@gmail.com>

On 06/23/2012 11:59 AM, KOSAKI Motohiro wrote:

> 
> One more.
> 
> 
>> +/*
>> + * NOTE:
>> + * Don't use set_pageblock_migratetype(page, MIGRATE_ISOLATE) direclty.
>> + * Instead, use {un}set_pageblock_isolate.
>> + */
>>  void set_pageblock_migratetype(struct page *page, int migratetype)
>>  {
>>         if (unlikely(page_group_by_mobility_disabled))
> 
> I don't think we need this comment. please just add BUG_ON.


It adds new condition check in __rmqueue_fallback.
If it's okay, no problem.

But as you know, calling MIGRATE_ISOLATE is very very rare and we can
make sure it's no problem on existing code. So the problem is future
user and I hope they can look at the code comment before using and we mm
have strong review system rather than other subsystem, I believe. :)

If you can't agree, I am willing to add BUG_ON but not sure others
like it. (Especially, Mel).



-- 
Kind regards,
Minchan Kim

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  reply	other threads:[~2012-06-25  1:19 UTC|newest]

Thread overview: 28+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-06-20  6:12 Accounting problem of MIGRATE_ISOLATED freed page Minchan Kim
2012-06-20  6:32 ` KOSAKI Motohiro
2012-06-20  7:53   ` Minchan Kim
2012-06-20 12:44     ` Hillf Danton
2012-06-20 23:58       ` Minchan Kim
2012-06-20 20:19     ` KOSAKI Motohiro
2012-06-21  0:01       ` Minchan Kim
2012-06-21  1:39         ` KOSAKI Motohiro
2012-06-21  1:55           ` Minchan Kim
2012-06-21  2:45             ` KOSAKI Motohiro
2012-06-21  4:55               ` Minchan Kim
2012-06-21 10:52                 ` Kamezawa Hiroyuki
2012-06-21 17:22                   ` KOSAKI Motohiro
2012-06-22  1:05                   ` Minchan Kim
2012-06-22  6:45                     ` Minchan Kim
2012-06-23  2:56                       ` KOSAKI Motohiro
2012-06-25  1:10                         ` Minchan Kim
2012-06-23  2:59                       ` KOSAKI Motohiro
2012-06-25  1:19                         ` Minchan Kim [this message]
2012-06-23  4:38                       ` Kamezawa Hiroyuki
2012-06-25  1:01                         ` Minchan Kim
2012-06-25  4:18                           ` Minchan Kim
2012-06-22  7:22                     ` KOSAKI Motohiro
2012-06-22  7:56                       ` Aaditya Kumar
2012-06-22  8:13                         ` KOSAKI Motohiro
2012-06-21 11:02                 ` Aaditya Kumar
2012-06-22  1:20                   ` Minchan Kim
2012-06-22  2:08                     ` Aaditya Kumar

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