From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-3.9 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id E1F62C04A6B for ; Fri, 10 May 2019 23:17:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id AF08120881 for ; Fri, 10 May 2019 23:17:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727407AbfEJXRY (ORCPT ); Fri, 10 May 2019 19:17:24 -0400 Received: from mx.ewheeler.net ([66.155.3.69]:58630 "EHLO mx.ewheeler.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726944AbfEJXRY (ORCPT ); Fri, 10 May 2019 19:17:24 -0400 Received: from localhost (localhost [127.0.0.1]) by mx.ewheeler.net (Postfix) with ESMTP id CC6C0A0692; Fri, 10 May 2019 23:17:23 +0000 (UTC) X-Virus-Scanned: amavisd-new at ewheeler.net Received: from mx.ewheeler.net ([127.0.0.1]) by localhost (mx.ewheeler.net [127.0.0.1]) (amavisd-new, port 10024) with LMTP id yfMugx9mXySL; Fri, 10 May 2019 23:17:23 +0000 (UTC) Received: from mx.ewheeler.net (mx.ewheeler.net [66.155.3.69]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by mx.ewheeler.net (Postfix) with ESMTPSA id 170AEA067D; Fri, 10 May 2019 23:17:23 +0000 (UTC) Date: Fri, 10 May 2019 23:17:20 +0000 (UTC) From: Eric Wheeler X-X-Sender: lists@mx.ewheeler.net To: Sasha Levin cc: Paolo Valente , Jens Axboe , "open list:BFQ I/O SCHEDULER" , open list , Eric Wheeler , stable@vger.kernel.org Subject: Re: [PATCH] bfq: backport: update internal depth state when queue depth changes In-Reply-To: <20190510201855.GB14410@sasha-vm> Message-ID: References: <1557510992-18506-1-git-send-email-stable@lists.ewheeler.net> <20190510201855.GB14410@sasha-vm> User-Agent: Alpine 2.11 (LRH 23 2013-08-11) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On Fri, 10 May 2019, Sasha Levin wrote: > On Fri, May 10, 2019 at 10:56:32AM -0700, Eric Wheeler wrote: > >From: Jens Axboe > > > >commit 77f1e0a52d26242b6c2dba019f6ebebfb9ff701e upstream > > > >A previous commit moved the shallow depth and BFQ depth map calculations > >to be done at init time, moving it outside of the hotter IO path. This > >potentially causes hangs if the users changes the depth of the scheduler > >map, by writing to the 'nr_requests' sysfs file for that device. > > > >Add a blk-mq-sched hook that allows blk-mq to inform the scheduler if > >the depth changes, so that the scheduler can update its internal state. > > > >Signed-off-by: Eric Wheeler > >Tested-by: Kai Krakow > >Reported-by: Paolo Valente > >Fixes: f0635b8a416e ("bfq: calculate shallow depths at init time") > >Signed-off-by: Jens Axboe > >Cc: stable@vger.kernel.org > > I wasn't clear on what was backported here, so I've queued the upstream > version on 4.19 and 4.14, it doesn't seem to be relevant to older > branches. Thanks Sasha. We needed it for 4.19, I wasn't sure how far it would patch back so I left the version off. BFQ was merged in 4.12 iirc, so if it patched against 4.14, then 4.19 and 4.14 are the only ones that need it. -- Eric Wheeler > > -- > Thanks, > Sasha >