From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from caramon.arm.linux.org.uk ([217.147.92.249]:33559 "EHLO caramon.arm.linux.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755172AbXGQSTS (ORCPT ); Tue, 17 Jul 2007 14:19:18 -0400 Date: Tue, 17 Jul 2007 19:18:43 +0100 From: Russell King Subject: Re: + sparc64-rename-tlb_flush_mmu.patch added to -mm tree Message-ID: <20070717181843.GB16147@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> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1184680583.21357.67.camel@localhost> Sender: linux-arch-owner@vger.kernel.org To: Martin Schwidefsky Cc: Andrew Morton , linux-arch@vger.kernel.org, davem@davemloft.net, hugh@veritas.com List-ID: 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? > > And it should have been loudly pointed out to various arch maintainers so > > they have an opportunity to implement the optimisation which it offers. > > The idea behind the optimization of this patch is that for a full mm > flush (tlb_gather_mmu called with full_mm_flush==1) a single > flush_tlb_mm is enough to remove all TLBs of the mm. New ones cannot be > created since full_mm_flush==1 only for exit_mmap. The same is true for > a normal unmap if there is only one user of the mm and the mm is the > currently active mm. > > -- > blue skies, > Martin. > > "Reality continues to ruin my life." - Calvin. > > --- > Subject: [PATCH] avoid tlb gather restarts. > > From: Martin Schwidefsky > > If need_resched() is false in the inner loop of unmap_vmas it is > unnecessary to do a full blown tlb_finish_mmu / tlb_gather_mmu for > each ZAP_BLOCK_SIZE ptes. Do a tlb_flush_mmu() instead. That gives > architectures with a non-generic tlb flush implementation room for > optimization. The tlb_flush_mmu primitive is a available with the > generic tlb flush code, the ia64_tlb_flush_mm needs to be renamed > and a dummy function is added to arm and arm26. This description sounds sane. Nothing really jumps out as a problem from reading the patch. -- Russell King Linux kernel 2.6 ARM Linux - http://www.arm.linux.org.uk/ maintainer of: