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Date: Wed, 02 Jul 2008 12:30:39 +0900
From: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
To: "MinChan Kim" <minchan.kim@gmail.com>
Subject: Re: [resend][PATCH -mm] split_lru: fix pagevec_move_tail() doesn't treat unevictable page
Cc: kosaki.motohiro@jp.fujitsu.com, "Rik van Riel" <riel@redhat.com>,
       LKML <linux-kernel@vger.kernel.org>, linux-mm <linux-mm@kvack.org>,
       "Lee Schermerhorn" <Lee.Schermerhorn@hp.com>,
       "Andrew Morton" <akpm@linux-foundation.org>
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Hi Kim-san,

> Hi, Rik and Kosaki-san
> 
> I want to know exact race situation for remaining git log.
> As you know, git log is important for me who is newbie to understand source
> 
> There are many possibility in this race problem.
> 
> Did you use hugepage in this test ?
> I think that If you used hugepage, it seems to happen following race.

I don't use hugepage. but use SYSV-shmem.
so following scenario is very reasonable.

OK.
I resend my patch with following description.


> 
> --------------
> 
> CPU1                                                           CPU2
> 
> shm_unlock
> scan_mapping_unevictable_pages
> check_move_unevictable_page
> ClearPageUnevictable                                 rotate_reclaimable_page
> 
> PageUnevictable(page) return 0
> SetPageUnevictable
> list_move(LRU_UNEVICTABLE)
> 
> local_irq_save
> 
> pagevec_move_tail
> 
> Do you think it is possible ?