From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752769AbZHXQvO (ORCPT ); Mon, 24 Aug 2009 12:51:14 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752456AbZHXQvO (ORCPT ); Mon, 24 Aug 2009 12:51:14 -0400 Received: from srv5.dvmed.net ([207.36.208.214]:58419 "EHLO mail.dvmed.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752154AbZHXQvN (ORCPT ); Mon, 24 Aug 2009 12:51:13 -0400 Message-ID: <4A92C500.4030109@garzik.org> Date: Mon, 24 Aug 2009 12:51:12 -0400 From: Jeff Garzik User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1.1) Gecko/20090814 Fedora/3.0-2.6.b3.fc11 Thunderbird/3.0b3 MIME-Version: 1.0 To: Jens Axboe CC: linux-kernel@vger.kernel.org, benh@kernel.crashing.org, htejun@gmail.com, bzolnier@gmail.com, alan@lxorguk.ukuu.org.uk, akpm@linux-foundation.org Subject: Re: [PATCH 4/7] libata: use lazy workqueues for the pio task References: <1251100616-28604-1-git-send-email-jens.axboe@oracle.com> <1251100616-28604-5-git-send-email-jens.axboe@oracle.com> <4A92C081.50207@garzik.org> <20090824164214.GO12579@kernel.dk> In-Reply-To: <20090824164214.GO12579@kernel.dk> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-Spam-Score: -4.4 (----) X-Spam-Report: SpamAssassin version 3.2.5 on srv5.dvmed.net summary: Content analysis details: (-4.4 points, 5.0 required) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 08/24/2009 12:42 PM, Jens Axboe wrote: > On Mon, Aug 24 2009, Jeff Garzik wrote: >> No objections to the code, operationally... >> >> But it is disappointing that the "1 thread on UP" problem is not solved >> while changing this libata area. Is there no way to specify a minimum >> lazy-thread count? >> >> A key problem continues to be tying to the number of CPUs, which is >> quite inappropriate for libata. > > We'll solve that next, the first problem is reducing the per-cpu > threads. Lots of places use per-cpu workqueues because that is what is > available, not necessarily because it's an appropriate choice. Like the > ata_wq above, it's not even a good fit. Agreed + sounds great. Thanks -- both for hacking libata for this, and more generally, for attacking the too-many-kthreads problem! :) It's just sad how many unused workqueue threads hang about, on every modern Linux box. Jeff