From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from caramon.arm.linux.org.uk ([217.147.92.249]:35293 "EHLO caramon.arm.linux.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750893AbXGQVPW (ORCPT ); Tue, 17 Jul 2007 17:15:22 -0400 Date: Tue, 17 Jul 2007 22:14:45 +0100 From: Russell King Subject: Re: + sparc64-rename-tlb_flush_mmu.patch added to -mm tree Message-ID: <20070717211445.GC16147@flint.arm.linux.org.uk> References: <200707170748.l6H7m1so005969@imap1.linux-foundation.org> <20070717005551.cdb9504e.akpm@linux-foundation.org> <20070717010324.833fee7e.akpm@linux-foundation.org> <1184680583.21357.67.camel@localhost> <20070717181843.GB16147@flint.arm.linux.org.uk> <20070717120820.86a50e75.akpm@linux-foundation.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20070717120820.86a50e75.akpm@linux-foundation.org> Sender: linux-arch-owner@vger.kernel.org To: Andrew Morton Cc: Martin Schwidefsky , linux-arch@vger.kernel.org, davem@davemloft.net, hugh@veritas.com List-ID: On Tue, Jul 17, 2007 at 12:08:20PM -0700, Andrew Morton wrote: > On Tue, 17 Jul 2007 19:18:43 +0100 Russell King wrote: > > > On Tue, Jul 17, 2007 at 03:56:23PM +0200, Martin Schwidefsky wrote: > > > On Tue, 2007-07-17 at 01:03 -0700, Andrew Morton wrote: > > > > OK, I don't understand how this patch works - from a quick glance it > > > > appears to be forgetting to flush stuff altogether on arm and arm26 at > > > > least and I see no sign that Russell, Tony and Ian have even seen it. > > > > > > Added linux-arch so that affected arch-maintainers can comment. > > > > Having a little more information about Andrew's concern would be nice. > > Under what circumstances do you think we're forgetting to flush stuff? > > > > "quick glance". ARM's tlb_flush_mmu() becomes a no-op and I though that > some real tlb_finish_mmu() got replaced by that. But I didn't look very > closely. I don't think ARM will have a problem with this change. In the fullmm case, tlb_finish_mmu() will flush the entire mm, so missing out the flush for each chunk is itself a worthwhile optimisation. In the !fullmm case, tlb_finish_mmu() does nothing as far as flushing is concerned, and in any case does nothing with it's start and end variables. So I think this patch suits us just fine. -- Russell King Linux kernel 2.6 ARM Linux - http://www.arm.linux.org.uk/ maintainer of: