From mboxrd@z Thu Jan 1 00:00:00 1970 From: KAMEZAWA Hiroyuki Subject: [PATCH 4/12] memcg make page->mapping NULL before calling uncharge Date: Thu, 25 Sep 2008 15:16:39 +0900 Message-ID: <20080925151639.5e2ddea4.kamezawa.hiroyu@jp.fujitsu.com> References: <20080925151124.25898d22.kamezawa.hiroyu@jp.fujitsu.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20080925151124.25898d22.kamezawa.hiroyu@jp.fujitsu.com> Sender: linux-kernel-owner@vger.kernel.org To: KAMEZAWA Hiroyuki Cc: "linux-mm@kvack.org" , "balbir@linux.vnet.ibm.com" , "nishimura@mxp.nes.nec.co.jp" , "xemul@openvz.org" , Andrew Morton , LKML , Dave Hansen , ryov@valinux.co.jp List-Id: linux-mm.kvack.org This patch tries to make page->mapping to be NULL before mem_cgroup_uncharge_cache_page() is called. "page->mapping == NULL" is a good check for "whether the page is still radix-tree or not". This patch also adds BUG_ON() to mem_cgroup_uncharge_cache_page(); Signed-off-by: KAMEZAWA Hiroyuki mm/filemap.c | 2 +- mm/memcontrol.c | 1 + mm/migrate.c | 12 +++++++++--- 3 files changed, 11 insertions(+), 4 deletions(-) Index: mmotm-2.6.27-rc7+/mm/filemap.c =================================================================== --- mmotm-2.6.27-rc7+.orig/mm/filemap.c +++ mmotm-2.6.27-rc7+/mm/filemap.c @@ -116,12 +116,12 @@ void __remove_from_page_cache(struct pag { struct address_space *mapping = page->mapping; - mem_cgroup_uncharge_cache_page(page); radix_tree_delete(&mapping->page_tree, page->index); page->mapping = NULL; mapping->nrpages--; __dec_zone_page_state(page, NR_FILE_PAGES); BUG_ON(page_mapped(page)); + mem_cgroup_uncharge_cache_page(page); /* * Some filesystems seem to re-dirty the page even after Index: mmotm-2.6.27-rc7+/mm/memcontrol.c =================================================================== --- mmotm-2.6.27-rc7+.orig/mm/memcontrol.c +++ mmotm-2.6.27-rc7+/mm/memcontrol.c @@ -737,6 +737,7 @@ void mem_cgroup_uncharge_page(struct pag void mem_cgroup_uncharge_cache_page(struct page *page) { VM_BUG_ON(page_mapped(page)); + VM_BUG_ON(page->mapping); __mem_cgroup_uncharge_common(page, MEM_CGROUP_CHARGE_TYPE_CACHE); } Index: mmotm-2.6.27-rc7+/mm/migrate.c =================================================================== --- mmotm-2.6.27-rc7+.orig/mm/migrate.c +++ mmotm-2.6.27-rc7+/mm/migrate.c @@ -330,8 +330,6 @@ static int migrate_page_move_mapping(str __inc_zone_page_state(newpage, NR_FILE_PAGES); spin_unlock_irq(&mapping->tree_lock); - if (!PageSwapCache(newpage)) - mem_cgroup_uncharge_cache_page(page); return 0; } @@ -378,7 +376,15 @@ static void migrate_page_copy(struct pag #endif ClearPagePrivate(page); set_page_private(page, 0); - page->mapping = NULL; + /* page->mapping contains a flag for PageAnon() */ + if (PageAnon(page)) { + /* This page is uncharged at try_to_unmap(). */ + page->mapping = NULL; + } else { + /* Obsolete file cache should be uncharged */ + page->mapping = NULL; + mem_cgroup_uncharge_cache_page(page); + } /* * If any waiters have accumulated on the new page then