From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tejun Heo Subject: Re: [PATCH 2/3] workqueue: Add an API to create a singlethread workqueue attached to the current task's cgroup Date: Thu, 27 May 2010 18:56:20 +0200 Message-ID: <4BFEA434.6080405@kernel.org> References: <1274227491.2370.110.camel@w-sridhar.beaverton.ibm.com> <20100527091426.GA6308@redhat.com> <20100527124448.GA4241@redhat.com> <20100527131254.GB7974@redhat.com> <4BFE9ABA.6030907@kernel.org> <20100527163954.GA21710@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]:35418 "EHLO hera.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757964Ab0E0Q5r (ORCPT ); Thu, 27 May 2010 12:57:47 -0400 In-Reply-To: <20100527163954.GA21710@redhat.com> Sender: netdev-owner@vger.kernel.org List-ID: Hello, On 05/27/2010 06:39 PM, Michael S. Tsirkin wrote: >> Unless you're gonna convert every driver to use this >> special kind of workqueue (and what happens when multiple tasks from >> different cgroups share the driver?), > > We'll then create a workqueue per task. Each workqueue will have the > right cgroup. But we are not trying to selve the problem for > every driver. Ah... I see. You're gonna use multiple workqueues. Once concern that I have is that this is abuse of workqueue interface to certain level and depends on the implementation detail of workqueue rather than its intended usage model. stop_machine() was a similar case and in the end it was better served by a different mechanism built on kthread directly (cpu_stop). Wouldn't it be cleaner to use kthread directly for your case too? You're basically trying to use workqueue as a frontend to kthread, so... Thanks. -- tejun