Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932773AbaBEAGo (ORCPT ); Tue, 4 Feb 2014 19:06:44 -0500 Received: from mail.linuxfoundation.org ([140.211.169.12]:58764 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754888AbaBEAGn (ORCPT ); Tue, 4 Feb 2014 19:06:43 -0500 Date: Tue, 4 Feb 2014 16:06:41 -0800 From: Andrew Morton To: David Rientjes Cc: Holger Kiehl , Christoph Lameter , Rafael Aquini , Vlastimil Babka , Michal Hocko , Mel Gorman , linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [patch] mm, page_alloc: make first_page visible before PageTail Message-Id: <20140204160641.8f5d369eeb2d0318618d6d5f@linux-foundation.org> In-Reply-To: References: <20140203122052.GC2495@dhcp22.suse.cz> <20140203162036.GJ2495@dhcp22.suse.cz> <52EFC93D.3030106@suse.cz> X-Mailer: Sylpheed 3.2.0beta5 (GTK+ 2.24.10; x86_64-pc-linux-gnu) 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 On Tue, 4 Feb 2014 16:02:39 -0800 (PST) David Rientjes wrote: > Commit bf6bddf1924e ("mm: introduce compaction and migration for ballooned > pages") introduces page_count(page) into memory compaction which > dereferences page->first_page if PageTail(page). > > Introduce a store memory barrier to ensure page->first_page is properly > initialized so that code that does page_count(page) on pages off the lru > always have a valid p->first_page. Could we have a code comment please? Even checkpatch knows this rule! > Reported-by: Holger Kiehl What did Holger report? -- 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/