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=-1.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 A9F14C2BB55 for ; Fri, 10 Apr 2020 20:50:51 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 3E4962087E for ; Fri, 10 Apr 2020 20:50:51 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="0P7mev/G" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3E4962087E Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id A48128E0060; Fri, 10 Apr 2020 16:50:50 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 9D1608E004D; Fri, 10 Apr 2020 16:50:50 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 872448E0060; Fri, 10 Apr 2020 16:50:50 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0148.hostedemail.com [216.40.44.148]) by kanga.kvack.org (Postfix) with ESMTP id 6C4BE8E004D for ; Fri, 10 Apr 2020 16:50:50 -0400 (EDT) Received: from smtpin13.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with ESMTP id 2B829180AD802 for ; Fri, 10 Apr 2020 20:50:50 +0000 (UTC) X-FDA: 76693139460.13.jelly17_7bab9b4e1e402 X-HE-Tag: jelly17_7bab9b4e1e402 X-Filterd-Recvd-Size: 3473 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by imf03.hostedemail.com (Postfix) with ESMTP for ; Fri, 10 Apr 2020 20:50:49 +0000 (UTC) Received: from mail-ua1-f46.google.com (mail-ua1-f46.google.com [209.85.222.46]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id ABB8C21556 for ; Fri, 10 Apr 2020 20:50:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1586551848; bh=E2lIjVQW6WHTE9KKwKVRpfcewIc0INyzWKKWl09INeE=; h=References:In-Reply-To:From:Date:Subject:To:Cc:From; b=0P7mev/GDX4TO25pT6YSxb6T9GzfcDy6mq1N0KvqF4XuGCHykCWzAxCncn8cD3rFl jrIuG0w6yMC9q0cQ70aCh6/8OUfWQ0mhGjh9Vz9AwQ/EIiKBdgi7uyxEyIUA83lCHG sLZsoQytB6lAag7CJTN0IUz59JackHKIWtWaL5+U= Received: by mail-ua1-f46.google.com with SMTP id g24so1058001uan.10 for ; Fri, 10 Apr 2020 13:50:48 -0700 (PDT) X-Gm-Message-State: AGi0PuauxT1x2bSfK7Y8d4iLAS1fbzDRAUyFy7hCf/C+tECr5YVjKF9Q gLgyvzpDBrtWslQ2btszpVFuCK4nERGlDTe2Qoo= X-Google-Smtp-Source: APiQypI0tNOYGPf4/lvDfJ6zR/L+k8DJVTeWUu84CivCL0gCG2JrO97xvf/TqqE8GefE/AoaSI0o2rfUBF6Mvj8IRlE= X-Received: by 2002:ab0:6657:: with SMTP id b23mr4604209uaq.14.1586551847706; Fri, 10 Apr 2020 13:50:47 -0700 (PDT) MIME-Version: 1.0 References: <20200409214530.2413-1-mcgrof@kernel.org> <20200409214530.2413-6-mcgrof@kernel.org> <161e938d-929b-1fdb-ba77-56b839c14b5b@acm.org> <20200410143412.GK11244@42.do-not-panic.com> In-Reply-To: <20200410143412.GK11244@42.do-not-panic.com> From: Luis Chamberlain Date: Fri, 10 Apr 2020 14:50:40 -0600 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [RFC v2 5/5] block: revert back to synchronous request_queue removal To: Bart Van Assche Cc: Jens Axboe , Al Viro , Greg Kroah-Hartman , Steven Rostedt , Ingo Molnar , Jan Kara , Ming Lei , Nicolai Stange , Andrew Morton , Michal Hocko , yu kuai , linux-block@vger.kernel.org, Linux FS Devel , linux-mm , "linux-kernel@vger.kernel.org" , Omar Sandoval , Hannes Reinecke , Michal Hocko Content-Type: text/plain; charset="UTF-8" X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Fri, Apr 10, 2020 at 8:34 AM Luis Chamberlain wrote: > On Thu, Apr 09, 2020 at 08:12:21PM -0700, Bart Van Assche wrote: > > Please add a might_sleep() call in blk_put_queue() since with this patch > > applied it is no longer allowed to call blk_put_queue() from atomic context. > > Sure thing. On second though, I don't think blk_put_queue() would be the right place for might_sleep(), given we really only care about the *last* refcount decrement to 0. So I'll move it to blk_release_queue(). Granted, at that point we are too late, and we'd get a splat about this issue *iff* we really sleep. So yeah, I do suppose that forcing this check there still makes sense. Luis