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From: Balbir Singh <balbir@linux.vnet.ibm.com>
To: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: "linux-mm@kvack.org" <linux-mm@kvack.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"menage@google.com" <menage@google.com>,
	"nishimura@mxp.nes.nec.co.jp" <nishimura@mxp.nes.nec.co.jp>
Subject: Re: [RFC][PATCH 0/6] memcg updates (05/Nov)
Date: Thu, 06 Nov 2008 12:24:11 +0530	[thread overview]
Message-ID: <49129493.9070103@linux.vnet.ibm.com> (raw)
In-Reply-To: <20081105171637.1b393333.kamezawa.hiroyu@jp.fujitsu.com>

KAMEZAWA Hiroyuki wrote:
> Weekly (RFC) update for memcg.
> 
> This set includes
> 
> 1. change force_empty to do move account rather than forget all

I would like this to be selectable, please. We don't want to break behaviour and
not everyone would like to pay the cost of movement.

> 2. swap cache handling
> 3. mem+swap controller kconfig
> 4. swap_cgroup for rememver swap account information
> 5. mem+swap controller core
> 6. synchronize memcg's LRU and global LRU.
> 
> "1" is already sent, "6" is a newcomer.
> I'd like to push out "2" or "2-5" in the next week (if no bugs.)
> 
> after 6, next candidates are
>   - dirty_ratio handler
>   - account move at task move.
> 
> Some more explanation about purpose of "6". (see details in patch itself)
> Now, one of complicated logic in memcg is LRU handling. Because the place of
> lru_head depends on page_cgroup->mem_cgroup pointer, we have to take
> lock as following even under zone->lru_lock.
> ==
>   pc = lookup_page_cgroup(page);
>   if (!trylock_page_cgroup(pc))
>   	return -EBUSY;
> 
>    if (PageCgroupUsed(pc)) {
> 	struct mem_cgroup_per_zone *mz = page_cgroup_zoneinfo(pc);
> 	spin_lock_irqsave(&mz->lru_lock, flags);
> 	....some operation on LRU.
> 	spin_unlock_irqrestore(&mz->lru_lock, flags);
>    }
>    unlock_page_cgroup(pc);
> ==
> Sigh..
> 
> After "6", page_cgroup's LRU management can be done independently to some extent.
> == as
>   (zone->lru_lock is held here)
>   pc = lookup_page_cgroup(page);
>   list operation on pc.
>   (unlock zone->lru_lock)
> ==
> Maybe good for maintainance and as a bonus, we can make use of isolate_lru_page() when
> doing some racy operation.
> 
> 	isolate_lru_page(page);
> 	pc = lookup_page_cgroup(page);
> 	do some jobs.
> 	putback_lru_page(page);
> 
> Maybe this will be a help to implement "account move at task move".

Sounds promising!

-- 
	Balbir

  parent reply	other threads:[~2008-11-06  6:58 UTC|newest]

Thread overview: 27+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-11-05  8:16 KAMEZAWA Hiroyuki
2008-11-05  8:18 ` [RFC][PATCH 1/6] memcg: move all accounts to parent at rmdir() KAMEZAWA Hiroyuki
2008-11-05  8:20 ` [RFC][PATCH 2/6] memcg: handle swap cache KAMEZAWA Hiroyuki
2008-11-07  8:53   ` Daisuke Nishimura
2008-11-07  9:13     ` KAMEZAWA Hiroyuki
2008-11-05  8:20 ` [RFC][PATCH 3/6] memcg : mem+swap controller kconfig KAMEZAWA Hiroyuki
2008-11-06 11:07   ` Daisuke Nishimura
2008-11-05  8:21 ` [RFC][PATCH 4/6] memcg : swap cgroup KAMEZAWA Hiroyuki
2008-11-06 11:25   ` Daisuke Nishimura
2008-11-06 12:44     ` KAMEZAWA Hiroyuki
2008-11-07  1:19       ` Daisuke Nishimura
2008-11-05  8:23 ` [RFC][PATCH 5/6] memcg: mem+swap controller KAMEZAWA Hiroyuki
2008-11-07  9:02   ` Daisuke Nishimura
2008-11-07  9:19     ` KAMEZAWA Hiroyuki
2008-11-07 13:30       ` Daisuke Nishimura
2008-11-07 13:21   ` Daisuke Nishimura
2008-11-10  4:30   ` Daisuke Nishimura
2008-11-10  7:03     ` KAMEZAWA Hiroyuki
2008-11-05  8:24 ` [RFC][PATCH 6/6] memcg: synchronized LRU KAMEZAWA Hiroyuki
2008-11-06  6:54 ` Balbir Singh [this message]
2008-11-06  7:03   ` [RFC][PATCH 0/6] memcg updates (05/Nov) KAMEZAWA Hiroyuki
2008-11-06 10:41   ` [RFC][PATCH 7/6] memcg: add atribute (for change bahavior of rmdir) KAMEZAWA Hiroyuki
2008-11-06 11:59     ` Hugh Dickins
2008-11-06 12:47       ` [RFC][PATCH 7/6] memcg: add atribute (for change bahavior ofrmdir) KAMEZAWA Hiroyuki
2008-11-06 13:46     ` [RFC][PATCH 7/6] memcg: add atribute (for change bahavior of rmdir) Balbir Singh
2008-11-06 14:30       ` [RFC][PATCH 7/6] memcg: add atribute (for change bahavior ofrmdir) KAMEZAWA Hiroyuki
2008-11-07  1:12         ` KAMEZAWA Hiroyuki

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