From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail137.messagelabs.com (mail137.messagelabs.com [216.82.249.19]) by kanga.kvack.org (Postfix) with SMTP id 752D16B00B0 for ; Sun, 19 Dec 2010 21:33:23 -0500 (EST) Received: from m1.gw.fujitsu.co.jp ([10.0.50.71]) by fgwmail5.fujitsu.co.jp (Fujitsu Gateway) with ESMTP id oBK2XL79029465 for (envelope-from kamezawa.hiroyu@jp.fujitsu.com); Mon, 20 Dec 2010 11:33:21 +0900 Received: from smail (m1 [127.0.0.1]) by outgoing.m1.gw.fujitsu.co.jp (Postfix) with ESMTP id 3393445DE5E for ; Mon, 20 Dec 2010 11:33:21 +0900 (JST) Received: from s1.gw.fujitsu.co.jp (s1.gw.fujitsu.co.jp [10.0.50.91]) by m1.gw.fujitsu.co.jp (Postfix) with ESMTP id 16C6445DE58 for ; Mon, 20 Dec 2010 11:33:21 +0900 (JST) Received: from s1.gw.fujitsu.co.jp (localhost.localdomain [127.0.0.1]) by s1.gw.fujitsu.co.jp (Postfix) with ESMTP id EF14EE38001 for ; Mon, 20 Dec 2010 11:33:20 +0900 (JST) Received: from ml14.s.css.fujitsu.com (ml14.s.css.fujitsu.com [10.249.87.104]) by s1.gw.fujitsu.co.jp (Postfix) with ESMTP id BB28FE08001 for ; Mon, 20 Dec 2010 11:33:20 +0900 (JST) Date: Mon, 20 Dec 2010 11:27:33 +0900 From: KAMEZAWA Hiroyuki Subject: Re: [RFC 5/5] truncate: Remove unnecessary page release Message-Id: <20101220112733.064f2fe3.kamezawa.hiroyu@jp.fujitsu.com> In-Reply-To: <20101220112227.E566.A69D9226@jp.fujitsu.com> References: <02ab98b3a1450f7a1c31edc48ccc57e887cee900.1292604746.git.minchan.kim@gmail.com> <20101220112227.E566.A69D9226@jp.fujitsu.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org To: KOSAKI Motohiro Cc: Minchan Kim , Andrew Morton , linux-mm , LKML , Nick Piggin , Al Viro List-ID: On Mon, 20 Dec 2010 11:21:52 +0900 (JST) KOSAKI Motohiro wrote: > > This patch series changes remove_from_page_cache's page ref counting > > rule. page cache ref count is decreased in remove_from_page_cache. > > So we don't need call again in caller context. > > > > Cc: Nick Piggin > > Cc: Al Viro > > Cc: linux-mm@kvack.org > > Signed-off-by: Minchan Kim > > --- > > mm/truncate.c | 1 - > > 1 files changed, 0 insertions(+), 1 deletions(-) > > > > diff --git a/mm/truncate.c b/mm/truncate.c > > index 9ee5673..8decb93 100644 > > --- a/mm/truncate.c > > +++ b/mm/truncate.c > > @@ -114,7 +114,6 @@ truncate_complete_page(struct address_space *mapping, struct page *page) > > * calls cleancache_put_page (and note page->mapping is now NULL) > > */ > > cleancache_flush_page(mapping, page); > > - page_cache_release(page); /* pagecache ref */ > > return 0; > > Do we _always_ have stable page reference here? IOW, I can assume > cleancache_flush_page() doesn't cause NULL deref? > Hmm, my review was bad. I think cleancache_flush_page() here should eat (mapping, index) as argument rather than "page". BTW, I can't understand == void __cleancache_flush_page(struct address_space *mapping, struct page *page) { /* careful... page->mapping is NULL sometimes when this is called */ int pool_id = mapping->host->i_sb->cleancache_poolid; struct cleancache_filekey key = { .u.key = { 0 } }; == Why above is safe... I think (mapping,index) should be passed instead of page. -Kame -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom policy in Canada: sign http://dissolvethecrtc.ca/ Don't email: email@kvack.org