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 ESMTP id 455926B00AC for ; Sun, 19 Dec 2010 21:27:53 -0500 (EST) Received: by iwn40 with SMTP id 40so2790796iwn.14 for ; Sun, 19 Dec 2010 18:27:48 -0800 (PST) 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 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Sender: owner-linux-mm@kvack.org To: KOSAKI Motohiro Cc: Andrew Morton , linux-mm , LKML , Nick Piggin , Al Viro List-ID: 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 >> --- >> =A0mm/truncate.c | =A0 =A01 - >> =A01 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) >> =A0 =A0 =A0 =A0* calls cleancache_put_page (and note page->mapping is no= w NULL) >> =A0 =A0 =A0 =A0*/ >> =A0 =A0 =A0 cleancache_flush_page(mapping, page); >> - =A0 =A0 page_cache_release(page); =A0 =A0 =A0 /* pagecache ref */ >> =A0 =A0 =A0 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? > > > > --=20 Kind regards, Minchan Kim -- 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