From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jan Kiszka Subject: Re: [PATCH 2/2] KVM: Convert read-only users of vm_list to RCU Date: Tue, 15 Feb 2011 15:08:12 +0100 Message-ID: <4D5A88CC.8020707@siemens.com> References: <4D512EF7.8040409@siemens.com> <4D512F3B.1080107@siemens.com> <20110215123202.GA3731@amt.cnet> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: Avi Kivity , kvm , Zachary Amsden To: Marcelo Tosatti Return-path: Received: from goliath.siemens.de ([192.35.17.28]:23929 "EHLO goliath.siemens.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754988Ab1BOOI2 (ORCPT ); Tue, 15 Feb 2011 09:08:28 -0500 In-Reply-To: <20110215123202.GA3731@amt.cnet> Sender: kvm-owner@vger.kernel.org List-ID: On 2011-02-15 13:32, Marcelo Tosatti wrote: > On Tue, Feb 08, 2011 at 12:55:39PM +0100, Jan Kiszka wrote: >> Only for walking the list of VMs, we do not need to hold the preemption >> disabling kvm_lock. Convert stat services, the cpufreq callback and >> mmu_shrink to RCU. For the latter, special care is required to >> synchronize its list_move_tail with kvm_destroy_vm. >> >> Signed-off-by: Jan Kiszka > > Jan, > > What is the motivation for this change? > See http://thread.gmane.org/gmane.linux.kernel/1097043 However, this proposal turned out to be incorrect. The strategy is now to remove the stats users and reduce the lock-holding time of mmu_shrink differently. Jan -- Siemens AG, Corporate Technology, CT T DE IT 1 Corporate Competence Center Embedded Linux