From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S964810AbXBYMHJ (ORCPT ); Sun, 25 Feb 2007 07:07:09 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S964821AbXBYMHJ (ORCPT ); Sun, 25 Feb 2007 07:07:09 -0500 Received: from smtp.osdl.org ([65.172.181.24]:33845 "EHLO smtp.osdl.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S964810AbXBYMHI (ORCPT ); Sun, 25 Feb 2007 07:07:08 -0500 Date: Sun, 25 Feb 2007 04:06:57 -0800 From: Andrew Morton To: Nick Piggin Cc: linux-kernel@vger.kernel.org, npiggin@suse.de, linux-mm@kvack.org Subject: Re: [patch 3/3] mm: fix PageUptodate memorder Message-Id: <20070225040657.eb4fc159.akpm@linux-foundation.org> In-Reply-To: <20070215051851.7443.65811.sendpatchset@linux.site> References: <20070215051822.7443.30110.sendpatchset@linux.site> <20070215051851.7443.65811.sendpatchset@linux.site> X-Mailer: Sylpheed version 2.2.4 (GTK+ 2.8.19; i686-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 X-Mailing-List: linux-kernel@vger.kernel.org What an unpleasing patchset. I really really hope we really have a bug in there, and that all this crap isn't pointless uglification. We _do_ need a flush_dcaceh_page() in all cases which you're concerned about. Perhaps we should stick the appropriate barriers in there. > On Thu, 15 Feb 2007 08:31:31 +0100 (CET) Nick Piggin wrote: > +static inline void SetNewPageUptodate(struct page *page) > +{ > + /* > + * S390 sets page dirty bit on IO operations, which is why it is > + * cleared in SetPageUptodate. This is not an issue for newly > + * allocated pages that are brought uptodate by zeroing memory. > + */ > + smp_wmb(); > + __set_bit(PG_uptodate, &(page)->flags); > +} __SetPageUptodate() might be more conventional. Boy we'd better get the callers of this little handgrenade right.