From mboxrd@z Thu Jan 1 00:00:00 1970 From: Xiao Guangrong Subject: Re: [PATCH 0/8] KVM: Reduce mmu_lock hold time when zapping mmu pages Date: Wed, 23 Jan 2013 18:44:52 +0800 Message-ID: <50FFBF24.3000203@linux.vnet.ibm.com> References: <20130123191231.d66489d2.yoshikawa_takuya_b1@lab.ntt.co.jp> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Cc: mtosatti@redhat.com, gleb@redhat.com, kvm@vger.kernel.org To: Takuya Yoshikawa Return-path: Received: from e23smtp08.au.ibm.com ([202.81.31.141]:48692 "EHLO e23smtp08.au.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754595Ab3AWKpB (ORCPT ); Wed, 23 Jan 2013 05:45:01 -0500 Received: from /spool/local by e23smtp08.au.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Wed, 23 Jan 2013 20:43:26 +1000 Received: from d23relay04.au.ibm.com (d23relay04.au.ibm.com [9.190.234.120]) by d23dlp02.au.ibm.com (Postfix) with ESMTP id 3475D2BB004E for ; Wed, 23 Jan 2013 21:44:56 +1100 (EST) Received: from d23av02.au.ibm.com (d23av02.au.ibm.com [9.190.235.138]) by d23relay04.au.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id r0NAX9vS15663234 for ; Wed, 23 Jan 2013 21:33:09 +1100 Received: from d23av02.au.ibm.com (loopback [127.0.0.1]) by d23av02.au.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id r0NAist6030602 for ; Wed, 23 Jan 2013 21:44:55 +1100 In-Reply-To: <20130123191231.d66489d2.yoshikawa_takuya_b1@lab.ntt.co.jp> Sender: kvm-owner@vger.kernel.org List-ID: On 01/23/2013 06:12 PM, Takuya Yoshikawa wrote: > This patch set mitigates another mmu_lock hold time issue. Although > this is not enough and I'm thinking of additional work already, this > alone can reduce the lock hold time to some extent. > It is not worth doing this kind of complex thing, usually, only a few pages on the invalid list. The *really* heavily case is kvm_mmu_zap_all() which can be speeded up by using generation number, this is a todo work in kvm wiki: http://www.linux-kvm.org/page/TODO: O(1) mmu invalidation using a generation number I am doing this work for some weeks and will post the patch out during these days.