Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755499Ab2BFUQQ (ORCPT ); Mon, 6 Feb 2012 15:16:16 -0500 Received: from casper.infradead.org ([85.118.1.10]:55087 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754175Ab2BFUQP (ORCPT ); Mon, 6 Feb 2012 15:16:15 -0500 Message-ID: <4F303506.9000201@kernel.dk> Date: Mon, 06 Feb 2012 21:16:06 +0100 From: Jens Axboe MIME-Version: 1.0 To: Tejun Heo CC: Linus Torvalds , Vivek Goyal , Shaohua Li , lkml , Knut Petersen , mroos@linux.ee Subject: Re: [patch]block: fix ioc locking warning References: <1328514611.21268.66.camel@sli10-conroe> <20120206151219.GC30752@redhat.com> <4F2FFB21.9000202@kernel.dk> <20120206163721.GF30752@redhat.com> <20120206164428.GA21292@google.com> <20120206172706.GB21292@google.com> In-Reply-To: <20120206172706.GB21292@google.com> X-Enigmail-Version: 1.3.5 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1286 Lines: 35 On 2012-02-06 18:27, Tejun Heo wrote: > Hello, > > On Mon, Feb 06, 2012 at 08:58:49AM -0800, Linus Torvalds wrote: >> On Mon, Feb 6, 2012 at 8:44 AM, Tejun Heo wrote: >>> >>> Yeah, this seems better to me. Jens, if you're gonna amend the >>> commit, please consider collapsing the following patch into the >>> original patch too. Thanks. >> >> Guys, is it *really* worth it to do all these crazy games? >> >> How bad is it to just always use the async freeing, instead of this >> clearly very fragile crazy direct-freeing-with-serious-locking-issues >> thing? > > It's one wq scheduling on exit for any task which has issued an IO. I > don't think it would matter except for task fork/exit microbenchs (or > workloads which approximate to that). I'll get some measurements and > strip the optimization if it doesn't really show up. One (arguably stupid) thing that some users do do is something like: $ find . -exec grep foo '{}' \; So that would probably be a good pathological test case for this. -- Jens Axboe -- 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/