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=-2.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no 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 24B09ECE58E for ; Fri, 11 Oct 2019 23:20:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id F2C392190F for ; Fri, 11 Oct 2019 23:20:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726595AbfJKXUh (ORCPT ); Fri, 11 Oct 2019 19:20:37 -0400 Received: from mail105.syd.optusnet.com.au ([211.29.132.249]:33931 "EHLO mail105.syd.optusnet.com.au" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726345AbfJKXUh (ORCPT ); Fri, 11 Oct 2019 19:20:37 -0400 Received: from dread.disaster.area (pa49-181-198-88.pa.nsw.optusnet.com.au [49.181.198.88]) by mail105.syd.optusnet.com.au (Postfix) with ESMTPS id 1835C36268A; Sat, 12 Oct 2019 10:20:33 +1100 (AEDT) Received: from dave by dread.disaster.area with local (Exim 4.92.2) (envelope-from ) id 1iJ4D3-0007jx-0D; Sat, 12 Oct 2019 10:20:33 +1100 Date: Sat, 12 Oct 2019 10:20:32 +1100 From: Dave Chinner To: Matthew Wilcox Cc: linux-xfs@vger.kernel.org, linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, Jens Axboe Subject: Re: [PATCH 14/26] mm: back off direct reclaim on excessive shrinker deferral Message-ID: <20191011232032.GN16973@dread.disaster.area> References: <20191009032124.10541-1-david@fromorbit.com> <20191009032124.10541-15-david@fromorbit.com> <20191011162105.GU32665@bombadil.infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20191011162105.GU32665@bombadil.infradead.org> User-Agent: Mutt/1.10.1 (2018-07-13) X-Optus-CM-Score: 0 X-Optus-CM-Analysis: v=2.2 cv=D+Q3ErZj c=1 sm=1 tr=0 a=ocld+OpnWJCUTqzFQA3oTA==:117 a=ocld+OpnWJCUTqzFQA3oTA==:17 a=jpOVt7BSZ2e4Z31A5e1TngXxSK0=:19 a=kj9zAlcOel0A:10 a=XobE76Q3jBoA:10 a=7-415B0cAAAA:8 a=JuDxSlhT3OO6blO4plAA:9 a=CjuIK1q_8ugA:10 a=biEYGPWJfzWAr4FL6Ov7:22 Sender: linux-xfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-xfs@vger.kernel.org On Fri, Oct 11, 2019 at 09:21:05AM -0700, Matthew Wilcox wrote: > On Wed, Oct 09, 2019 at 02:21:12PM +1100, Dave Chinner wrote: > > + if ((reclaim_state->deferred_objects > > > + sc->nr_scanned - nr_scanned) && > > + (reclaim_state->deferred_objects > > > + reclaim_state->scanned_objects)) { > > + wait_iff_congested(BLK_RW_ASYNC, HZ/50); > > Unfortunately, Jens broke wait_iff_congested() recently, and doesn't plan > to fix it. We need to come up with another way to estimate congestion. I know, all the ways the block layer is broken are right there in the cover letter at the end of the v1 patchset description from more than 2 months ago. When people work out how to fix congestion detection and backoff again, this can be updated at the same time. Cheers, Dave. -- Dave Chinner david@fromorbit.com