From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S964868AbbEAPrY (ORCPT ); Fri, 1 May 2015 11:47:24 -0400 Received: from mail-qk0-f174.google.com ([209.85.220.174]:35653 "EHLO mail-qk0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S964852AbbEAPrR (ORCPT ); Fri, 1 May 2015 11:47:17 -0400 Date: Fri, 1 May 2015 11:47:13 -0400 From: Tejun Heo To: Christoph Hellwig Cc: Ming Lei , Jens Axboe , Linux Kernel Mailing List , "Justin M. Forbes" , Jeff Moyer , "v4.0" Subject: Re: [PATCH v6] block: loop: avoiding too many pending per work I/O Message-ID: <20150501154713.GD1949@htj.duckdns.org> References: <1430450881-10881-1-git-send-email-ming.lei@canonical.com> <20150501101737.GA18577@infradead.org> <20150501142221.GC1949@htj.duckdns.org> <20150501150545.GA10705@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20150501150545.GA10705@infradead.org> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, May 01, 2015 at 08:05:45AM -0700, Christoph Hellwig wrote: > > Maybe just cap max_active to NR_OF_LOOP_DEVS * 16 or sth? But idk, > > how many concurrent workers are we talking about and why are we > > capping per-queue concurrency from worker pool side instead of command > > tag side? > > Also we probably should have per device workqueues to start with.. Yeah, that's an option. The only thing is that each workqueue would have to be tagged WQ_RESCUER and end up with separate rescuer task, which usually isn't big a deal but there are setups where a lot of loop devices are used and it may sting a bit. Thanks. -- tejun