From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tejun Heo Subject: Re: [PATCH 3/3] vhost: apply cpumask and cgroup to vhost workers Date: Tue, 01 Jun 2010 12:56:33 +0200 Message-ID: <4C04E761.4020800@kernel.org> References: <20100527173207.GA21880@redhat.com> <4BFEE216.2070807@kernel.org> <20100528150830.GB21880@redhat.com> <4BFFE742.2060205@kernel.org> <20100530112925.GB27611@redhat.com> <4C02C961.9050606@kernel.org> <20100531152221.GB2987@redhat.com> <4C03D983.9010905@kernel.org> <20100531160020.GC3067@redhat.com> <4C04D453.9040208@kernel.org> <20100601101703.GB9178@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: Oleg Nesterov , Sridhar Samudrala , netdev , lkml , "kvm@vger.kernel.org" , Andrew Morton , Dmitri Vorobiev , Jiri Kosina , Thomas Gleixner , Ingo Molnar , Andi Kleen To: "Michael S. Tsirkin" Return-path: Received: from hera.kernel.org ([140.211.167.34]:41769 "EHLO hera.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753128Ab0FAK5Q (ORCPT ); Tue, 1 Jun 2010 06:57:16 -0400 In-Reply-To: <20100601101703.GB9178@redhat.com> Sender: netdev-owner@vger.kernel.org List-ID: Hello, On 06/01/2010 12:17 PM, Michael S. Tsirkin wrote: > Something that I wanted to figure out - what happens if the > CPU mask limits us to a certain CPU that subsequently goes offline? The thread gets unbound during the last steps of cpu offlining. > Will e.g. flush block forever or until that CPU comes back? > Also, does singlethreaded workqueue behave in the same way? So, things will proceed as usual although the thread will lose its affinity. Singlethread wqs don't bind their workers (and they shouldn't! :-). MT ones explicitly manage workers according to cpu up/down events. Thanks. -- tejun