linux-kernel - Re: [BUGFIX][PATCH 1/4] memcg: fix limit estimation at reclaim for hugepage

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Message-ID: <AANLkTikCjKCtjhRH-ZVsEQN-Luz==8g8e60uxhCTeD2w@mail.gmail.com>
Date:	Fri, 28 Jan 2011 17:04:16 +0900
From:	Minchan Kim <minchan.kim@...il.com>
To:	KAMEZAWA Hiroyuki <kamezawa.hiroyu@...fujitsu.com>
Cc:	Daisuke Nishimura <nishimura@....nes.nec.co.jp>,
	"linux-mm@...ck.org" <linux-mm@...ck.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"hannes@...xchg.org" <hannes@...xchg.org>,
	"balbir@...ux.vnet.ibm.com" <balbir@...ux.vnet.ibm.com>
Subject: Re: [BUGFIX][PATCH 1/4] memcg: fix limit estimation at reclaim for hugepage

Hi Kame,

On Fri, Jan 28, 2011 at 1:58 PM, KAMEZAWA Hiroyuki
<kamezawa.hiroyu@...fujitsu.com> wrote:
> How about this ?
> ==
> From: KAMEZAWA Hiroyuki <kamezawa.hiroyu@...fujitsu.com>
>
> Current memory cgroup's code tends to assume page_size == PAGE_SIZE
> and arrangement for THP is not enough yet.
>
> This is one of fixes for supporing THP. This adds
> mem_cgroup_check_margin() and checks whether there are required amount of
> free resource after memory reclaim. By this, THP page allocation
> can know whether it really succeeded or not and avoid infinite-loop
> and hangup.
>
> Total fixes for do_charge()/reclaim memory will follow this patch.

If this patch is only related to THP, I think patch order isn't good.
Before applying [2/4], huge page allocation will retry without
reclaiming and loop forever by below part.

@@ -1854,9 +1858,6 @@ static int __mem_cgroup_do_charge(struct
 	} else
 		mem_over_limit = mem_cgroup_from_res_counter(fail_res, res);

-	if (csize > PAGE_SIZE) /* change csize and retry */
-		return CHARGE_RETRY;
-
 	if (!(gfp_mask & __GFP_WAIT))
 		return CHARGE_WOULDBLOCK;

Am I missing something?

-- 
Kind regards,
Minchan Kim
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