From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934135AbeEWSvt (ORCPT ); Wed, 23 May 2018 14:51:49 -0400 Received: from mail-yw0-f194.google.com ([209.85.161.194]:39041 "EHLO mail-yw0-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933928AbeEWSvq (ORCPT ); Wed, 23 May 2018 14:51:46 -0400 X-Google-Smtp-Source: AB8JxZphDC1cj42Db3ZuZu3o2gDBKzv7BfuMza1dubJYH0VGB+SSXn/q2F0mzHBBZ9D0nYumUt3wEw== Date: Wed, 23 May 2018 11:51:43 -0700 From: Tejun Heo To: "Paul E. McKenney" Cc: Jens Axboe , linux-kernel@vger.kernel.org, Jan Kara , Andrew Morton , kernel-team@fb.com Subject: Re: [PATCH] bdi: Move cgroup bdi_writeback to a dedicated low concurrency workqueue Message-ID: <20180523185143.GS1718769@devbig577.frc2.facebook.com> References: <20180523175632.GO1718769@devbig577.frc2.facebook.com> <20180523183907.GZ3803@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180523183907.GZ3803@linux.vnet.ibm.com> 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 Wed, May 23, 2018 at 11:39:07AM -0700, Paul E. McKenney wrote: > > While this resolves the problem at hand, it might be a good idea to > > isolate rcu_exp_work to its own workqueue too as it can be used from > > various paths and is prone to this sort of indirect A-A deadlocks. > > Commit ad7c946b35ad4 ("rcu: Create RCU-specific workqueues with rescuers") > was accepted into mainline this past merge window. Does that do what > you want, or are you looking for something else? Ah, that does it. Sorry, was looking at an older kernel. Thanks. -- tejun