Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751952Ab0LTCdX (ORCPT ); Sun, 19 Dec 2010 21:33:23 -0500 Received: from fgwmail6.fujitsu.co.jp ([192.51.44.36]:54011 "EHLO fgwmail6.fujitsu.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751160Ab0LTCdW (ORCPT ); Sun, 19 Dec 2010 21:33:22 -0500 X-SecurityPolicyCheck-FJ: OK by FujitsuOutboundMailChecker v1.3.1 Date: Mon, 20 Dec 2010 11:27:33 +0900 From: KAMEZAWA Hiroyuki To: KOSAKI Motohiro Cc: Minchan Kim , Andrew Morton , linux-mm , LKML , Nick Piggin , Al Viro 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> Organization: FUJITSU Co. LTD. X-Mailer: Sylpheed 3.0.3 (GTK+ 2.10.14; 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: 1870 Lines: 54 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 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/