From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753416Ab2H3JRl (ORCPT ); Thu, 30 Aug 2012 05:17:41 -0400 Received: from mail-pb0-f46.google.com ([209.85.160.46]:51673 "EHLO mail-pb0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753154Ab2H3JRk (ORCPT ); Thu, 30 Aug 2012 05:17:40 -0400 Date: Thu, 30 Aug 2012 02:17:39 -0700 From: Tejun Heo To: Lai Jiangshan Cc: linux-kernel@vger.kernel.org Subject: Re: [PATCH 4/9 V3] workqueue: add non_manager_role_manager_mutex_unlock() Message-ID: <20120830091739.GA10874@dhcp-172-17-108-109.mtv.corp.google.com> References: <1346259120-6216-1-git-send-email-laijs@cn.fujitsu.com> <1346259120-6216-5-git-send-email-laijs@cn.fujitsu.com> <20120829182510.GB2258@dhcp-172-17-108-109.mtv.corp.google.com> <503F2F51.8000301@cn.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <503F2F51.8000301@cn.fujitsu.com> User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello, Lai. On Thu, Aug 30, 2012 at 05:16:01PM +0800, Lai Jiangshan wrote: > gcwq_unbind_fn() is unsafe even it is called from a work item. > so we need non_manager_role_manager_mutex_unlock(). > > If rebind_workers() is called from a work item, it is safe when there is > no CPU_INTENSIVE items. but we can't disable CPU_INTENSIVE items, > so it is still unsafe, we need non_manager_role_manager_mutex_unlock() too. Can you please elaborate? Why is it not safe if there are CPU_INTENSIVE items? Thanks. -- tejun