From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx128.postini.com [74.125.245.128]) by kanga.kvack.org (Postfix) with SMTP id 4A9B56B0002 for ; Mon, 1 Apr 2013 20:37:48 -0400 (EDT) Date: Tue, 2 Apr 2013 09:37:46 +0900 From: Minchan Kim Subject: Re: [PATCH] THP: Use explicit memory barrier Message-ID: <20130402003746.GA30444@blaptop> References: <1364773535-26264-1-git-send-email-minchan@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: owner-linux-mm@kvack.org List-ID: To: David Rientjes Cc: Andrew Morton , linux-kernel@vger.kernel.org, linux-mm@kvack.org, Mel Gorman , Andrea Arcangeli , Hugh Dickins On Mon, Apr 01, 2013 at 04:35:38PM -0700, David Rientjes wrote: > On Mon, 1 Apr 2013, 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. > > > > Is this the same issue that Andrea responded to in the "thp and memory > barrier assumptions" thread at http://marc.info/?t=134333512700004 ? Yes and Peter pointed out further step. Thanks for pointing out. Not that I know that Andrea alreay noticed it, I don't care about this patch. Remaining question is Kame's one. Isn't there anyone could answer it? > > -- > 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 -- 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/ . Don't email: email@kvack.org