From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757815AbZJPJXq (ORCPT ); Fri, 16 Oct 2009 05:23:46 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1757465AbZJPJXq (ORCPT ); Fri, 16 Oct 2009 05:23:46 -0400 Received: from eddie.linux-mips.org ([78.24.191.182]:34985 "EHLO eddie.linux-mips.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753388AbZJPJXp (ORCPT ); Fri, 16 Oct 2009 05:23:45 -0400 Date: Fri, 16 Oct 2009 11:24:18 +0200 From: Ralf Baechle To: Minchan Kim Cc: Atsushi Nemoto , lkml , linux-mips , Chungki woo Subject: Re: BUG? linux-mips flush_dcache_page Message-ID: <20091016092418.GA3686@linux-mips.org> References: <20091016141719.de606482.minchan.kim@barrios-desktop> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20091016141719.de606482.minchan.kim@barrios-desktop> User-Agent: Mutt/1.5.19 (2009-01-05) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Oct 16, 2009 at 02:17:19PM +0900, Minchan Kim wrote: > Many code of kernel fs usually allocate high page and flush. > But flush_dcache_page of mips checks PageHighMem to avoid flush > so that data consistency is broken, I think. What processor and cache configuration? > I found it's by you and Atsushi-san on 585fa724. > Why do we need the check? > Could you elaborte please? The if statement exists because __flush_dcache_page would crash if a page is not mapped. This of course isn't correct but that wasn't a problem since highmem still is only supported on machines that don't have aliases. Ralf