From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751824AbdGRTgV (ORCPT ); Tue, 18 Jul 2017 15:36:21 -0400 Received: from mail-qt0-f170.google.com ([209.85.216.170]:36100 "EHLO mail-qt0-f170.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751532AbdGRTgT (ORCPT ); Tue, 18 Jul 2017 15:36:19 -0400 Date: Tue, 18 Jul 2017 15:36:15 -0400 From: Tejun Heo To: Christoph Hellwig Cc: Alexei Potashnik , linux-kernel@vger.kernel.org Subject: Re: [PATCH] workqueue: doc change for ST behavior on NUMA systems Message-ID: <20170718193615.GB3365493@devbig577.frc2.facebook.com> References: <20170718191829.GA11583@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20170718191829.GA11583@infradead.org> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jul 18, 2017 at 12:18:29PM -0700, Christoph Hellwig wrote: > On Tue, Jul 18, 2017 at 11:12:53AM -0700, Alexei Potashnik wrote: > > NUMA rework of workqueue made the combination of max_active of 1 and > > WQ_UNBOUND insufficient to guarantee ST behavior system wide. > > > > alloc_ordered_queue should now be used instead. > > Eww. And how many existing users might be broken by that? Good point. create_singlethread_workqueue() maps to alloc_ordered_workqueue(), so they're all good. Only the ones which got converted to the new interface incorrectly would be broken. I probably should make WQ_UNBOUND / 1 behave as ordered. I'll think more about it. Thanks! -- tejun