From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail202.messagelabs.com (mail202.messagelabs.com [216.82.254.227]) by kanga.kvack.org (Postfix) with SMTP id 8652D6B004F for ; Tue, 12 May 2009 04:15:17 -0400 (EDT) Received: from mt1.gw.fujitsu.co.jp ([10.0.50.74]) by fgwmail7.fujitsu.co.jp (Fujitsu Gateway) with ESMTP id n4C8FQIx021642 for (envelope-from kamezawa.hiroyu@jp.fujitsu.com); Tue, 12 May 2009 17:15:29 +0900 Received: from smail (m4 [127.0.0.1]) by outgoing.m4.gw.fujitsu.co.jp (Postfix) with ESMTP id BF12D45DE55 for ; Tue, 12 May 2009 17:15:26 +0900 (JST) Received: from s4.gw.fujitsu.co.jp (s4.gw.fujitsu.co.jp [10.0.50.94]) by m4.gw.fujitsu.co.jp (Postfix) with ESMTP id 9E38145DE54 for ; Tue, 12 May 2009 17:15:26 +0900 (JST) Received: from s4.gw.fujitsu.co.jp (localhost.localdomain [127.0.0.1]) by s4.gw.fujitsu.co.jp (Postfix) with ESMTP id 883861DB8037 for ; Tue, 12 May 2009 17:15:26 +0900 (JST) Received: from ml14.s.css.fujitsu.com (ml14.s.css.fujitsu.com [10.249.87.104]) by s4.gw.fujitsu.co.jp (Postfix) with ESMTP id 2C1811DB8043 for ; Tue, 12 May 2009 17:15:26 +0900 (JST) Date: Tue, 12 May 2009 17:13:56 +0900 From: KAMEZAWA Hiroyuki Subject: [PATCH][BUGFIX] memcg: fix for deadlock between lock_page_cgroup and mapping tree_lock Message-Id: <20090512171356.3d3a7554.kamezawa.hiroyu@jp.fujitsu.com> In-Reply-To: <20090512170007.ad7f5c7b.nishimura@mxp.nes.nec.co.jp> References: <20090512104401.28edc0a8.kamezawa.hiroyu@jp.fujitsu.com> <20090512140648.0974cb10.nishimura@mxp.nes.nec.co.jp> <20090512160901.8a6c5f64.kamezawa.hiroyu@jp.fujitsu.com> <20090512170007.ad7f5c7b.nishimura@mxp.nes.nec.co.jp> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org To: Daisuke Nishimura Cc: "linux-mm@kvack.org" , "balbir@linux.vnet.ibm.com" , "akpm@linux-foundation.org" , mingo@elte.hu, "linux-kernel@vger.kernel.org" List-ID: On Tue, 12 May 2009 17:00:07 +0900 Daisuke Nishimura wrote: > hmm, I see. > cache_charge is outside of tree_lock, so moving uncharge would make sense. > IMHO, we should make the period of spinlock as small as possible, > and charge/uncharge of pagecache/swapcache is protected by page lock, not tree_lock. > How about this ? == From: KAMEZAWA Hiroyuki As Nishimura pointed out, mapping->tree_lock can be aquired from interrupt context. Then, following dead lock can occur. Assume "A" as a page. CPU0: lock_page_cgroup(A) interrupted -> take mapping->tree_lock. CPU1: take mapping->tree_lock -> lock_page_cgroup(A) This patch tries to fix above deadlock by moving memcg's hook to out of mapping->tree_lock. After this patch, lock_page_cgroup() is not called under mapping->tree_lock. Making Nishimura's first fix more fundamanetal for avoiding to add special case. Reported-by: Daisuke Nishimura Signed-off-by: KAMEZAWA Hiroyuki --- mm/filemap.c | 6 +++--- mm/swap_state.c | 2 +- mm/truncate.c | 1 + mm/vmscan.c | 2 ++ 4 files changed, 7 insertions(+), 4 deletions(-) Index: mmotm-2.6.30-May07/mm/filemap.c =================================================================== --- mmotm-2.6.30-May07.orig/mm/filemap.c +++ mmotm-2.6.30-May07/mm/filemap.c @@ -121,7 +121,6 @@ void __remove_from_page_cache(struct pag 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 @@ -145,6 +144,7 @@ void remove_from_page_cache(struct page spin_lock_irq(&mapping->tree_lock); __remove_from_page_cache(page); spin_unlock_irq(&mapping->tree_lock); + mem_cgroup_uncharge_cache_page(page); } static int sync_page(void *word) @@ -476,13 +476,13 @@ int add_to_page_cache_locked(struct page if (likely(!error)) { mapping->nrpages++; __inc_zone_page_state(page, NR_FILE_PAGES); + spin_unlock_irq(&mapping->tree_lock); } else { page->mapping = NULL; + spin_unlock_irq(&mapping->tree_lock); mem_cgroup_uncharge_cache_page(page); page_cache_release(page); } - - spin_unlock_irq(&mapping->tree_lock); radix_tree_preload_end(); } else mem_cgroup_uncharge_cache_page(page); Index: mmotm-2.6.30-May07/mm/swap_state.c =================================================================== --- mmotm-2.6.30-May07.orig/mm/swap_state.c +++ mmotm-2.6.30-May07/mm/swap_state.c @@ -121,7 +121,6 @@ void __delete_from_swap_cache(struct pag total_swapcache_pages--; __dec_zone_page_state(page, NR_FILE_PAGES); INC_CACHE_INFO(del_total); - mem_cgroup_uncharge_swapcache(page, ent); } /** @@ -191,6 +190,7 @@ void delete_from_swap_cache(struct page __delete_from_swap_cache(page); spin_unlock_irq(&swapper_space.tree_lock); + mem_cgroup_uncharge_swapcache(page, ent); swap_free(entry); page_cache_release(page); } Index: mmotm-2.6.30-May07/mm/truncate.c =================================================================== --- mmotm-2.6.30-May07.orig/mm/truncate.c +++ mmotm-2.6.30-May07/mm/truncate.c @@ -359,6 +359,7 @@ invalidate_complete_page2(struct address BUG_ON(page_has_private(page)); __remove_from_page_cache(page); spin_unlock_irq(&mapping->tree_lock); + mem_cgroup_uncharge_cache_page(page); page_cache_release(page); /* pagecache ref */ return 1; failed: Index: mmotm-2.6.30-May07/mm/vmscan.c =================================================================== --- mmotm-2.6.30-May07.orig/mm/vmscan.c +++ mmotm-2.6.30-May07/mm/vmscan.c @@ -477,10 +477,12 @@ static int __remove_mapping(struct addre swp_entry_t swap = { .val = page_private(page) }; __delete_from_swap_cache(page); spin_unlock_irq(&mapping->tree_lock); + mem_cgroup_uncharge_swapcache(page); swap_free(swap); } else { __remove_from_page_cache(page); spin_unlock_irq(&mapping->tree_lock); + mem_cgroup_uncharge_cache_page(page); } return 1; -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. 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