Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757422AbYGDJDi (ORCPT ); Fri, 4 Jul 2008 05:03:38 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753519AbYGDJDa (ORCPT ); Fri, 4 Jul 2008 05:03:30 -0400 Received: from fgwmail6.fujitsu.co.jp ([192.51.44.36]:52301 "EHLO fgwmail6.fujitsu.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753507AbYGDJD2 (ORCPT ); Fri, 4 Jul 2008 05:03:28 -0400 Date: Fri, 4 Jul 2008 18:09:13 +0900 From: KAMEZAWA Hiroyuki To: Andrew Morton Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, "hugh@veritas.com" , "balbir@linux.vnet.ibm.com" , "nishimura@mxp.nes.nec.co.jp" , "yamamoto@valinux.co.jp" Subject: [PATCH] memcg: handle shmem's swap cache (Was 2.6.26-rc8-mm1 Message-Id: <20080704180913.bb1a3fc6.kamezawa.hiroyu@jp.fujitsu.com> In-Reply-To: <20080703020236.adaa51fa.akpm@linux-foundation.org> References: <20080703020236.adaa51fa.akpm@linux-foundation.org> Organization: Fujitsu X-Mailer: Sylpheed 2.4.2 (GTK+ 2.10.11; i686-pc-mingw32) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3031 Lines: 81 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 Index: test-2.6.26-rc8-mm1/mm/memcontrol.c =================================================================== --- test-2.6.26-rc8-mm1.orig/mm/memcontrol.c +++ test-2.6.26-rc8-mm1/mm/memcontrol.c @@ -687,11 +687,45 @@ __mem_cgroup_uncharge_common(struct page VM_BUG_ON(pc->page != page); - if ((ctype == MEM_CGROUP_CHARGE_TYPE_MAPPED) - && ((pc->flags & PAGE_CGROUP_FLAG_CACHE) - || page_mapped(page) - || PageSwapCache(page))) + /* + * File Cache + * If called with MEM_CGROUP_CHARGE_TYPE_MAPPED, check page->mapping. + * add_to_page_cache() .... charged before inserting radix-tree. + * remove_from_page_cache() .... uncharged at removing from radix-tree. + * page->mapping && !PageAnon(page) catches file cache. + * + * Anon/Shmem.....We check PageSwapCache(page). + * Anon .... charged before mapped. + * Shmem .... charged at add_to_page_cache() as usual File Cache. + * + * This page will be finally uncharged when removed from swap-cache + * + * we treat 2 cases here. + * A. anonymous page B. shmem. + * We never uncharge if page is marked as SwapCache. + * add_to_swap_cache() have nothing to do with charge/uncharge. + * SwapCache flag is deleted before delete_from_swap_cache() calls this + * + * shmem's behavior is following. (see shmem.c/swap_state.c also) + * at swap-out: + * 0. add_to_page_cache()//charged at page creation. + * 1. add_to_swap_cache() (marked as SwapCache) + * 2. remove_from_page_cache(). (calls this.) + * (finally) delete_from_swap_cache(). (calls this.) + * at swap-in: + * 3. add_to_swap_cache() (no charge here.) + * 4. add_to_page_cache() (charged here.) + * 5. delete_from_swap_cache() (calls this.) + * PageSwapCache(page) catches "2". + * page->mapping && !PageAnon() catches "5" and avoid uncharging. + */ + if (PageSwapCache(page)) goto unlock; + /* called from unmap or delete_from_swap_cache() */ + if ((ctype == MEM_CGROUP_CHARGE_TYPE_MAPPED) + && (page_mapped(page) + || (page->mapping && !PageAnon(page))))/* alive cache ? */ + goto unlock; mz = page_cgroup_zoneinfo(pc); spin_lock_irqsave(&mz->lru_lock, flags); -- 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/