From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932691Ab0CLL0F (ORCPT ); Fri, 12 Mar 2010 06:26:05 -0500 Received: from mx1.redhat.com ([209.132.183.28]:16134 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932219Ab0CLL0B (ORCPT ); Fri, 12 Mar 2010 06:26:01 -0500 Organization: Red Hat UK Ltd. Registered Address: Red Hat UK Ltd, Amberley Place, 107-111 Peascod Street, Windsor, Berkshire, SI4 1TE, United Kingdom. Registered in England and Wales under Company Registration No. 3798903 From: David Howells In-Reply-To: <4B99CB0F.1090505@kernel.org> References: <4B99CB0F.1090505@kernel.org> <1267187000-18791-1-git-send-email-tj@kernel.org> <29029.1268232771@redhat.com> To: Tejun Heo Cc: dhowells@redhat.com, torvalds@linux-foundation.org, mingo@elte.hu, peterz@infradead.org, awalls@radix.net, linux-kernel@vger.kernel.org, jeff@garzik.org, akpm@linux-foundation.org, jens.axboe@oracle.com, rusty@rustcorp.com.au, cl@linux-foundation.org, arjan@linux.intel.com, avi@redhat.com, johannes@sipsolutions.net, andi@firstfloor.org, oleg@redhat.com Subject: Re: [PATCHSET] workqueue: concurrency managed workqueue, take#4 Date: Fri, 12 Mar 2010 11:23:55 +0000 Message-ID: <3491.1268393035@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Tejun Heo wrote: > > So when a work item is running on a CPU, any work items it queues > > (including requeueing itself) will be queued upon that CPU for attention > > only by that CPU (assuming that CPU doesn't get pulled out)? > > Yes, that's the one of the characteristics of workqueue. For IO bound > stuff, it usually is a plus. Hmmm. So when, say, an FS-Cache index object finishes creating itself on disk and then releases all the several thousand data objects waiting on that event so that they can then create themselves, it will do this by calling queue_work() on each of them in turn. I take it this will stack them all up on that one CPU's work queue. David