Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S935013AbaLLQFq (ORCPT ); Fri, 12 Dec 2014 11:05:46 -0500 Received: from mail-oi0-f43.google.com ([209.85.218.43]:64666 "EHLO mail-oi0-f43.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933666AbaLLQFo (ORCPT ); Fri, 12 Dec 2014 11:05:44 -0500 MIME-Version: 1.0 In-Reply-To: <1418379595-6281-6-git-send-email-laijs@cn.fujitsu.com> References: <1418379595-6281-1-git-send-email-laijs@cn.fujitsu.com> <1418379595-6281-6-git-send-email-laijs@cn.fujitsu.com> From: KOSAKI Motohiro Date: Fri, 12 Dec 2014 11:05:24 -0500 Message-ID: Subject: Re: [PATCH 5/5] workqueue: retry on NUMA_NO_NODE when create_worker() fails To: Lai Jiangshan Cc: LKML , Tejun Heo , Yasuaki Ishimatsu , "Gu, Zheng" , tangchen , Hiroyuki KAMEZAWA Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Dec 12, 2014 at 5:19 AM, Lai Jiangshan wrote: > A pwq bound to a specified node might be last long or even forever after > the node was offline. Especially when this pwq has some back-to-back work > items which requeue themselves and cause the pwq can't quit. > > This kinds of pwqs will cause their own pools busy and maybe create workers. > This pools will fail on create_worker() since the node is offline. > > This case is extremely rare, but it is possible. And we hope create_worker() > to be fault-tolerant in this case and other different cases when the node > is lack of memory, for example, create_worker() can try to allocate memory > from the whole system rather than only the target node, the most important > thing is making some progress. > > So the solution is that, when the create_worker() fails on a specified node, > it will retry with NUMA_NO_NODE for further allocation. The code looks correct. But I don't think this issue depend on node offlining. The allocation may also fail if node has no memory. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/