From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756077AbZJAM5Q (ORCPT ); Thu, 1 Oct 2009 08:57:16 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755524AbZJAM5M (ORCPT ); Thu, 1 Oct 2009 08:57:12 -0400 Received: from mx1.redhat.com ([209.132.183.28]:58088 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755376AbZJAM5L (ORCPT ); Thu, 1 Oct 2009 08:57:11 -0400 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: <1254384558-1018-1-git-send-email-tj@kernel.org> References: <1254384558-1018-1-git-send-email-tj@kernel.org> To: Tejun Heo Cc: jeff@garzik.org, mingo@elte.hu, linux-kernel@vger.kernel.org, akpm@linux-foundation.org, jens.axboe@oracle.com, rusty@rustcorp.com.au, cl@linux-foundation.org, dhowells@redhat.com, arjan@linux.intel.com Subject: Re: [RFC PATCHSET] workqueue: implement concurrency managed workqueue Date: Thu, 01 Oct 2009 13:53:49 +0100 Message-ID: <9942.1254401629@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Sounds interesting as a replacement for slow-work. Some thoughts for you: The most important features of slow-work are: (1) Work items are not re-entered whilst they are executing. (2) The slow-work facility keeps references on its work items by asking the client to get and put on the client's refcount. (3) The slow-work facility can create a lot more threads than the number of CPUs on a system, and the system doesn't grind to a halt if they're all taken up with long term I/O (performing several mkdirs for example). I think you have (1) and (3) covered, but I'm unsure about (2). Also, does it actually make sense to bind threads that are performing long-term I/O to particular CPUs? Threads that are going to spend a lot more time sleeping on disk I/O than actually running on a CPU? David