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Date: Fri, 21 Jan 2011 09:21:18 +0900
From: nishimura@mxp.nes.nec.co.jp
Subject: Re: [PATCH 4/4] memcg: fix rmdir, force_empty with THP
To: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
        Johannes Weiner <hannes@cmpxchg.org>
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>> > @@ -2278,17 +2287,23 @@ static int mem_cgroup_move_parent(struct
>> >  		goto out;
>> >  	if (isolate_lru_page(page))
>> >  		goto put;
>> > +	/* The page is isolated from LRU and we have no race with splitting */
>> > +	charge = PAGE_SIZE << compound_order(page);
>> 
>> Why is LRU isolation preventing the splitting?
>> 
Oops! It seems that this comment made me confuse 'split' and 'collapse'.
Yes, it's 'collapse', not 'split', that is prevented by isolation.

> I use compound_lock now. I'll post clean up.
> 
I'll wait for your patch.

Thanks,
Daisuke Nishimura.