Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756553Ab2BNHWI (ORCPT ); Tue, 14 Feb 2012 02:22:08 -0500 Received: from mail-vw0-f46.google.com ([209.85.212.46]:39050 "EHLO mail-vw0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751317Ab2BNHWF convert rfc822-to-8bit (ORCPT ); Tue, 14 Feb 2012 02:22:05 -0500 MIME-Version: 1.0 In-Reply-To: <20120214121314.6216e0aa.kamezawa.hiroyu@jp.fujitsu.com> References: <20120214120414.025625c2.kamezawa.hiroyu@jp.fujitsu.com> <20120214121314.6216e0aa.kamezawa.hiroyu@jp.fujitsu.com> From: Greg Thelen Date: Mon, 13 Feb 2012 23:21:45 -0800 Message-ID: Subject: Re: [PATCH 3/6 v4] memcg: remove PCG_MOVE_LOCK flag from page_cgroup. To: KAMEZAWA Hiroyuki Cc: "linux-mm@kvack.org" , "linux-kernel@vger.kernel.org" , "hannes@cmpxchg.org" , Michal Hocko , "akpm@linux-foundation.org" , Ying Han , Hugh Dickins Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8BIT X-System-Of-Record: true Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1358 Lines: 32 On Mon, Feb 13, 2012 at 7:13 PM, KAMEZAWA Hiroyuki wrote: > From ffd1b013fe294a80c12e3f30e85386135a6fb284 Mon Sep 17 00:00:00 2001 > From: KAMEZAWA Hiroyuki > 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() > > Signed-off-by: KAMEZAWA Hiroyuki Seems good. Thanks. Acked-by: Greg Thelen -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/