Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S936381Ab3DKPnI (ORCPT ); Thu, 11 Apr 2013 11:43:08 -0400 Received: from aserp1040.oracle.com ([141.146.126.69]:34712 "EHLO aserp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934954Ab3DKPnH (ORCPT ); Thu, 11 Apr 2013 11:43:07 -0400 Date: Thu, 11 Apr 2013 11:42:02 -0400 Subject: Re: [tip:x86/urgent] x86, mm: Patch out arch_flush_lazy_mmu_mode() when running on bare metal Message-ID: From: Konrad Rzeszutek Wilk To: Boris Ostrovsky Cc: "H. Peter Anvin" , mingo@kernel.org, linux-kernel@vger.kernel.org, jwboyer@redhat.com, tglx@linutronix.de, bp@suse.de MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 X-Source-IP: ucsinet21.oracle.com [156.151.31.93] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: 8bit X-MIME-Autoconverted: from base64 to 8bit by mail.home.local id r3BFh9eD004592 Content-Length: 1762 Lines: 41 I am sorry for top posting. Haven't figured out how to reply inline in the Android email client. Boris, could you repost it please? If I recall correctly the only question on that patch was whether to put stable@vger.kernel.org on it and it was decided (by Greg) that was OK. It is not an urgent patch though as it is only exposed with debug kernels. Boris Ostrovsky wrote: >On 04/10/2013 08:30 PM, tip-bot for Boris Ostrovsky wrote: >> Commit-ID: 511ba86e1d386f671084b5d0e6f110bb30b8eeb2 >> Gitweb: http://git.kernel.org/tip/511ba86e1d386f671084b5d0e6f110bb30b8eeb2 >> Author: Boris Ostrovsky >> AuthorDate: Sat, 23 Mar 2013 09:36:36 -0400 >> Committer: H. Peter Anvin >> CommitDate: Wed, 10 Apr 2013 11:25:10 -0700 >> >> x86, mm: Patch out arch_flush_lazy_mmu_mode() when running on bare metal >> >> Invoking arch_flush_lazy_mmu_mode() results in calls to >> preempt_enable()/disable() which may have performance impact. >> >> Since lazy MMU is not used on bare metal we can patch away >> arch_flush_lazy_mmu_mode() so that it is never called in such >> environment. >> >> [ hpa: the previous patch "Fix vmalloc_fault oops during lazy MMU >> updates" may cause a minor performance regression on >> bare metal. This patch resolves that performance regression. It is >> somewhat unclear to me if this is a good -stable candidate. ] > >I think this > > https://lkml.org/lkml/2013/2/26/420 > >was also part of lazy mmu set of patches but is missing in the latest >batch of >commits. > >-boris > ????{.n?+???????+%?????ݶ??w??{.n?+????{??G?????{ay?ʇڙ?,j??f???h?????????z_??(?階?ݢj"???m??????G????????????&???~???iO???z??v?^?m???? ????????I?