From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx162.postini.com [74.125.245.162]) by kanga.kvack.org (Postfix) with SMTP id C54B26B0002 for ; Sun, 31 Mar 2013 21:02:23 -0400 (EDT) Received: from m4.gw.fujitsu.co.jp (unknown [10.0.50.74]) by fgwmail6.fujitsu.co.jp (Postfix) with ESMTP id E18F83EE0C5 for ; Mon, 1 Apr 2013 10:02:20 +0900 (JST) Received: from smail (m4 [127.0.0.1]) by outgoing.m4.gw.fujitsu.co.jp (Postfix) with ESMTP id C47DF45DE50 for ; Mon, 1 Apr 2013 10:02:20 +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 A816945DE4F for ; Mon, 1 Apr 2013 10:02:20 +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 999C91DB803B for ; Mon, 1 Apr 2013 10:02:20 +0900 (JST) Received: from ml14.s.css.fujitsu.com (ml14.s.css.fujitsu.com [10.240.81.134]) by s4.gw.fujitsu.co.jp (Postfix) with ESMTP id 4B3BF1DB803F for ; Mon, 1 Apr 2013 10:02:20 +0900 (JST) Message-ID: <5158DC7D.2040607@jp.fujitsu.com> Date: Mon, 01 Apr 2013 10:01:49 +0900 From: Kamezawa Hiroyuki MIME-Version: 1.0 Subject: Re: [PATCH] THP: Use explicit memory barrier References: <1364773535-26264-1-git-send-email-minchan@kernel.org> In-Reply-To: <1364773535-26264-1-git-send-email-minchan@kernel.org> Content-Type: text/plain; charset=ISO-2022-JP Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Minchan Kim Cc: Andrew Morton , linux-kernel@vger.kernel.org, linux-mm@kvack.org, Mel Gorman , Andrea Arcangeli , Hugh Dickins (2013/04/01 8:45), Minchan Kim wrote: > __do_huge_pmd_anonymous_page depends on page_add_new_anon_rmap's > spinlock for making sure that clear_huge_page write become visible > after set set_pmd_at() write. > > But lru_cache_add_lru uses pagevec so it could miss spinlock > easily so above rule was broken so user may see inconsistent data. > This patch fixes it with using explict barrier rather than depending > on lru spinlock. > Hmm...how about do_anonymous_page() ? there are no comments/locks/barriers. Users can see non-zero value after page fault in theory ? Thanks, -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/ . Don't email: email@kvack.org