From mboxrd@z Thu Jan 1 00:00:00 1970 Received: with ECARTIS (v1.0.0; list linux-mips); Fri, 16 Oct 2009 11:23:06 +0200 (CEST) Received: from localhost.localdomain ([127.0.0.1]:52558 "EHLO h5.dl5rb.org.uk" rhost-flags-OK-OK-OK-FAIL) by ftp.linux-mips.org with ESMTP id S1492190AbZJPJXD (ORCPT ); Fri, 16 Oct 2009 11:23:03 +0200 Received: from h5.dl5rb.org.uk (localhost.localdomain [127.0.0.1]) by h5.dl5rb.org.uk (8.14.3/8.14.3) with ESMTP id n9G9OLLR004090; Fri, 16 Oct 2009 11:24:21 +0200 Received: (from ralf@localhost) by h5.dl5rb.org.uk (8.14.3/8.14.3/Submit) id n9G9OJpM004088; Fri, 16 Oct 2009 11:24:19 +0200 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) Return-Path: X-Envelope-To: <"|/home/ecartis/ecartis -s linux-mips"> (uid 0) X-Orcpt: rfc822;linux-mips@linux-mips.org Original-Recipient: rfc822;linux-mips@linux-mips.org X-archive-position: 24361 X-ecartis-version: Ecartis v1.0.0 Sender: linux-mips-bounce@linux-mips.org Errors-to: linux-mips-bounce@linux-mips.org X-original-sender: ralf@linux-mips.org Precedence: bulk X-list: linux-mips 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