Re: [PATCH 3/6] memcg: remove PCG_MOVE_LOCK flag from page_cgroup

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From: Johannes Weiner <hannes@cmpxchg.org>
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>,
	"akpm@linux-foundation.org" <akpm@linux-foundation.org>,
	Michal Hocko <mhocko@suse.cz>, Hugh Dickins <hughd@google.com>,
	Greg Thelen <gthelen@google.com>, Ying Han <yinghan@google.com>
Subject: Re: [PATCH 3/6] memcg: remove PCG_MOVE_LOCK flag from page_cgroup
Date: Mon, 20 Feb 2012 09:56:17 +0100	[thread overview]
Message-ID: <20120220085617.GC1677@cmpxchg.org> (raw)
In-Reply-To: <20120217182651.c12bfc5e.kamezawa.hiroyu@jp.fujitsu.com>

On Fri, Feb 17, 2012 at 06:26:51PM +0900, KAMEZAWA Hiroyuki wrote:
> >From 62a96c625be0c30fc5828d88685b6873ed254060 Mon Sep 17 00:00:00 2001
> From: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
> Date: Thu, 2 Feb 2012 11:49:59 +0900
> Subject: [PATCH 3/6] memcg: remove PCG_MOVE_LOCK flag from page_cgroup.
> 
> PCG_MOVE_LOCK is used for bit spinlock to avoid race between overwriting
> pc->mem_cgroup and page statistics accounting per memcg.
> This lock helps to avoid the race but the race is very rare because moving
> tasks between cgroup is not a usual job.
> So, it seems using 1bit per page is too costly.
> 
> This patch changes this lock as per-memcg spinlock and removes PCG_MOVE_LOCK.
> 
> If smaller lock is required, we'll be able to add some hashes but
> I'd like to start from this.
> 
> Changelog:
>   - fixed to pass memcg as an argument rather than page_cgroup.
>     and renamed from move_lock_page_cgroup() to move_lock_mem_cgroup()
> 
> Acked-by: Greg Thelen <gthelen@google.com>
> Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>

Acked-by: Johannes Weiner <hannes@cmpxchg.org>

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WARNING: multiple messages have this Message-ID (diff)

From: Johannes Weiner <hannes@cmpxchg.org>
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>,
	"akpm@linux-foundation.org" <akpm@linux-foundation.org>,
	Michal Hocko <mhocko@suse.cz>, Hugh Dickins <hughd@google.com>,
	Greg Thelen <gthelen@google.com>, Ying Han <yinghan@google.com>
Subject: Re: [PATCH 3/6] memcg: remove PCG_MOVE_LOCK flag from page_cgroup
Date: Mon, 20 Feb 2012 09:56:17 +0100	[thread overview]
Message-ID: <20120220085617.GC1677@cmpxchg.org> (raw)
In-Reply-To: <20120217182651.c12bfc5e.kamezawa.hiroyu@jp.fujitsu.com>

On Fri, Feb 17, 2012 at 06:26:51PM +0900, KAMEZAWA Hiroyuki wrote:
> >From 62a96c625be0c30fc5828d88685b6873ed254060 Mon Sep 17 00:00:00 2001
> From: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
> Date: Thu, 2 Feb 2012 11:49:59 +0900
> Subject: [PATCH 3/6] memcg: remove PCG_MOVE_LOCK flag from page_cgroup.
> 
> PCG_MOVE_LOCK is used for bit spinlock to avoid race between overwriting
> pc->mem_cgroup and page statistics accounting per memcg.
> This lock helps to avoid the race but the race is very rare because moving
> tasks between cgroup is not a usual job.
> So, it seems using 1bit per page is too costly.
> 
> This patch changes this lock as per-memcg spinlock and removes PCG_MOVE_LOCK.
> 
> If smaller lock is required, we'll be able to add some hashes but
> I'd like to start from this.
> 
> Changelog:
>   - fixed to pass memcg as an argument rather than page_cgroup.
>     and renamed from move_lock_page_cgroup() to move_lock_mem_cgroup()
> 
> Acked-by: Greg Thelen <gthelen@google.com>
> Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>

Acked-by: Johannes Weiner <hannes@cmpxchg.org>

next prev parent reply	other threads:[~2012-02-20  8:56 UTC|newest]

Thread overview: 35+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-02-17  9:24 [PATCH 0/6] page cgroup diet v5 KAMEZAWA Hiroyuki
2012-02-17  9:24 ` KAMEZAWA Hiroyuki
2012-02-17  9:25 ` [PATCH 1/6] memcg: remove EXPORT_SYMBOL(mem_cgroup_update_page_stat) KAMEZAWA Hiroyuki
2012-02-17  9:25   ` KAMEZAWA Hiroyuki
2012-02-20  8:54   ` Johannes Weiner
2012-02-20  8:54     ` Johannes Weiner
2012-02-17  9:26 ` [PATCH 2/6] memcg: simplify move_account() check KAMEZAWA Hiroyuki
2012-02-17  9:26   ` KAMEZAWA Hiroyuki
2012-02-20  8:55   ` Johannes Weiner
2012-02-20  8:55     ` Johannes Weiner
2012-02-17  9:26 ` [PATCH 3/6] memcg: remove PCG_MOVE_LOCK flag from page_cgroup KAMEZAWA Hiroyuki
2012-02-17  9:26   ` KAMEZAWA Hiroyuki
2012-02-20  8:56   ` Johannes Weiner [this message]
2012-02-20  8:56     ` Johannes Weiner
2012-02-17  9:27 ` [PATCH 4/6] memcg: use new logic for page stat accounting KAMEZAWA Hiroyuki
2012-02-17  9:27   ` KAMEZAWA Hiroyuki
2012-02-28 12:22   ` Johannes Weiner
2012-02-28 12:22     ` Johannes Weiner
2012-02-17  9:28 ` [PATCH 5/6] memcg: remove PCG_FILE_MAPPED KAMEZAWA Hiroyuki
2012-02-17  9:28   ` KAMEZAWA Hiroyuki
2012-02-18 13:39   ` Johannes Weiner
2012-02-18 13:39     ` Johannes Weiner
2012-02-18 14:43     ` Hillf Danton
2012-02-18 14:43       ` Hillf Danton
2012-02-19 23:52       ` KAMEZAWA Hiroyuki
2012-02-19 23:52         ` KAMEZAWA Hiroyuki
2012-02-17  9:28 ` [PATCH 6/6] memcg: fix performance of mem_cgroup_begin_update_page_stat() KAMEZAWA Hiroyuki
2012-02-17  9:28   ` KAMEZAWA Hiroyuki
2012-02-28 12:25   ` Johannes Weiner
2012-02-28 12:25     ` Johannes Weiner
2012-02-17 10:04 ` [PATCH 0/6] page cgroup diet v5 KAMEZAWA Hiroyuki
2012-02-17 21:45 ` Andrew Morton
2012-02-17 21:45   ` Andrew Morton
  -- strict thread matches above, loose matches on Subject: below --
2012-02-06 10:06 [RFC] [PATCH 0/6 v3] memcg: page cgroup diet KAMEZAWA Hiroyuki
2012-02-06 10:09 ` [PATCH 3/6] memcg: remove PCG_MOVE_LOCK flag from page_cgroup KAMEZAWA Hiroyuki
2012-02-06 10:09   ` KAMEZAWA Hiroyuki

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