Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751751Ab0LTC1u (ORCPT ); Sun, 19 Dec 2010 21:27:50 -0500 Received: from mail-iw0-f174.google.com ([209.85.214.174]:42515 "EHLO mail-iw0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751160Ab0LTC1t convert rfc822-to-8bit (ORCPT ); Sun, 19 Dec 2010 21:27:49 -0500 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type:content-transfer-encoding; b=F/wscQrjO3R55u6QS3gmJqnuKHdKoChGXpRzE7E9VqaZCU/wh0tE9Oi62/TAyWvDt4 lkklFIeW+/XqeTB2YOz+vp7ty70BgODkGCJMfa9h0YApdrvmBLQLzShqERQdcwSJDcDz Hgwj0DL84uAtEPhzn68ChlVKLvpdC9p0tpdsQ= MIME-Version: 1.0 In-Reply-To: <20101220112227.E566.A69D9226@jp.fujitsu.com> References: <02ab98b3a1450f7a1c31edc48ccc57e887cee900.1292604746.git.minchan.kim@gmail.com> <20101220112227.E566.A69D9226@jp.fujitsu.com> Date: Mon, 20 Dec 2010 11:27:48 +0900 Message-ID: Subject: Re: [RFC 5/5] truncate: Remove unnecessary page release From: Minchan Kim To: KOSAKI Motohiro Cc: Andrew Morton , linux-mm , LKML , Nick Piggin , Al Viro Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1461 Lines: 46 On Mon, Dec 20, 2010 at 11:21 AM, 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 I think so. Because the page is locked so caller have to hold a ref to unlock it. > cleancache_flush_page() doesn't cause NULL deref? > > > > -- Kind regards, Minchan Kim -- 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/