Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753880AbYGEFl0 (ORCPT ); Sat, 5 Jul 2008 01:41:26 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752133AbYGEFlS (ORCPT ); Sat, 5 Jul 2008 01:41:18 -0400 Received: from E23SMTP05.au.ibm.com ([202.81.18.174]:52018 "EHLO e23smtp05.au.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752088AbYGEFlR (ORCPT ); Sat, 5 Jul 2008 01:41:17 -0400 Message-ID: <486F0976.7010104@linux.vnet.ibm.com> Date: Sat, 05 Jul 2008 11:11:10 +0530 From: Balbir Singh Reply-To: balbir@linux.vnet.ibm.com Organization: IBM User-Agent: Thunderbird 2.0.0.14 (X11/20080515) MIME-Version: 1.0 To: KAMEZAWA Hiroyuki CC: Andrew Morton , linux-kernel@vger.kernel.org, linux-mm@kvack.org, "hugh@veritas.com" , "nishimura@mxp.nes.nec.co.jp" , "yamamoto@valinux.co.jp" Subject: Re: [PATCH] memcg: handle shmem's swap cache (Was 2.6.26-rc8-mm1 References: <20080703020236.adaa51fa.akpm@linux-foundation.org> <20080704180913.bb1a3fc6.kamezawa.hiroyu@jp.fujitsu.com> In-Reply-To: <20080704180913.bb1a3fc6.kamezawa.hiroyu@jp.fujitsu.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1337 Lines: 38 KAMEZAWA Hiroyuki wrote: > My swapcache accounting under memcg patch failed to catch tmpfs(shmem)'s one. > Can I test this under -mm tree ? > (If -mm is busy, I'm not in hurry.) > This patch works well in my box. > = > SwapCache handling fix. > > shmem's swapcache behavior is a little different from anonymous's one and > memcg failed to handle it. This patch tries to fix it. > > After this: > > Any page marked as SwapCache is not uncharged. (delelte_from_swap_cache() > delete the SwapCache flag.) > > To check a shmem-page-cache is alive or not we use > page->mapping && !PageAnon(page) instead of > pc->flags & PAGE_CGROUP_FLAG_CACHE. > > Signed-off-by: KAMEZAWA Hiroyuki Though I am not opposed to this, I do sit up and think if keeping the reference count around could avoid this complexity and from my point, the maintenance overhead of this logic/code (I fear there might be more special cases :( ) The trade-off is complexity versus the overhead of reference counting. -- Warm Regards, Balbir Singh Linux Technology Center IBM, ISTL -- 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/