From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1161926Ab2CPBjl (ORCPT ); Thu, 15 Mar 2012 21:39:41 -0400 Received: from wolverine02.qualcomm.com ([199.106.114.251]:61311 "EHLO wolverine02.qualcomm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1161704Ab2CPBji (ORCPT ); Thu, 15 Mar 2012 21:39:38 -0400 X-IronPort-AV: E=McAfee;i="5400,1158,6650"; a="170654284" Message-ID: <4F6299D9.9000004@codeaurora.org> Date: Thu, 15 Mar 2012 18:39:37 -0700 From: Stephen Boyd User-Agent: Mozilla/5.0 (X11; Linux i686 on x86_64; rv:8.0) Gecko/20111105 Thunderbird/8.0 MIME-Version: 1.0 To: "Rafael J. Wysocki" CC: Christian Lamparter , linux-kernel@vger.kernel.org, Linux PM mailing list , "Srivatsa S. Bhat" , alan@lxorguk.ukuu.org.uk, Linus Torvalds , Saravana Kannan , Greg Kroah-Hartman , Kay Sievers Subject: Re: [PATCH] firmware_class: Move request_firmware_nowait() to workqueues References: <1331841015-26684-1-git-send-email-sboyd@codeaurora.org> <201203152107.57501.chunkeey@googlemail.com> <4F624D32.9030801@codeaurora.org> <201203152331.14314.rjw@sisk.pl> In-Reply-To: <201203152331.14314.rjw@sisk.pl> Content-Type: text/plain; charset=ISO-8859-15 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 03/15/12 15:31, Rafael J. Wysocki wrote: > On Thursday, March 15, 2012, Stephen Boyd wrote: >> On 03/15/12 13:07, Christian Lamparter wrote: >>> On Thursday, March 15, 2012 08:50:15 PM Stephen Boyd wrote: >>>> Oddly enough a work_struct was already part of the firmware_work >>>> structure but nobody was using it. Instead of creating a new >>>> kthread for each request_firmware_nowait() just schedule the work >>>> on the system workqueue. This should avoid some overhead in >>>> forking new threads when they're not strictly necessary if >>>> workqueues are available. >>>> >>>> Signed-off-by: Stephen Boyd >>>> Cc: Greg Kroah-Hartman >>>> Cc: Kay Sievers >>>> Cc: Rafael J. Wysocki >>>> --- >>>> >>>> I saw this while looking at this problem we're having. >>> Correct me if I'm wrong, but wouldn't that stall all other >>> global workqueue tasks for up to 60 seconds [in worst case]? >>> >>> But I think we can get rid of the firmware_work work struct... >>> >> My understanding is that with concurrency managed workqueues when the >> work item blocks another will be scheduled to run almost immediately. So >> before that change by Tejun workqueues would have been a bad idea >> because it could have blocked up to 60 second but now it should be fine >> because that work item will just be put to sleep and another request >> will run. > Please read the description of system_wq in workqueue.h. > > You should have used either system_long_wq or system_nrt_wq (depending on > what you really need). > > Thanks. I think we can use system_nrt_wq then? Or maybe even the unbounded workqueue system_unbound_wq? -- Sent by an employee of the Qualcomm Innovation Center, Inc. The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum.