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=-5.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 28E80C433E6 for ; Wed, 27 Jan 2021 16:15:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D8E5B20798 for ; Wed, 27 Jan 2021 16:15:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1343941AbhA0QPc (ORCPT ); Wed, 27 Jan 2021 11:15:32 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38768 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235078AbhA0QNz (ORCPT ); Wed, 27 Jan 2021 11:13:55 -0500 Received: from mail-ed1-x52b.google.com (mail-ed1-x52b.google.com [IPv6:2a00:1450:4864:20::52b]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D6AB1C061756 for ; Wed, 27 Jan 2021 08:13:11 -0800 (PST) Received: by mail-ed1-x52b.google.com with SMTP id z22so3095002edb.9 for ; Wed, 27 Jan 2021 08:13:11 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=soleen.com; s=google; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=yCJr5LaWhWMU0GEv1VBLBRwE+7yrkKij+9EAYt1Xy1Y=; b=bPf2zHTV4+wJn2TwThn/ciUqtN5J+OBKLsllaBgPD9jYr7oo+SFzuqeWtlZyojcvxx 0Z3iEq8J+5enD78FQ4TqXtZen+55GTxa2Eg9espAPPmehigHIEbAnPLLan09hbTWaUYk zMs9FosvenRGKAXIdYMno2Fi8MfUjLuxPedQX0yXrdv/a4Mvi0acS81fB5jTtbPOv3Bg A9hdVjuOnlbd1ykNcWiZNKI2DivE2fxjHkE62bZJBMgcxsZITg6wz6zqfLT4AYyzH+pS o7OUrr4JZYb4U4h0DXZsWAZOtzStcCwsX6SCTrx3a//Mm0cJD7Npa1ZeOgJe27NVCpUL JEEQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=yCJr5LaWhWMU0GEv1VBLBRwE+7yrkKij+9EAYt1Xy1Y=; b=WisK+vu+fPsoBuDOXSznHd3MnERpIXTu/BBuW40LmqRBdBP2n7QYaUyVz4EkDGd86X zyQgVYXMHvfAJMd1I3TKFwkjWjwc5a0VJS4/+lGQ5zgMnh6ggNL/dBXLicryXt2kVNyK RkofVWGBeoSvH3kBxM1aUYMG2TNE0D+OGyAHkRx+7zrC6fmYRAmpGxR/pHjjDTpy3SV4 I1HILZeZFgzNYyQTLW6y0ETA07ZIHrQr9Hkms+XgHXFTL3rwXoUMd0gSmxjd0HAvLxdj lWZao4A82yIt9F+Ss8HLxXv9A9tLApMuz+xDS6urvkBdWwBmUON3a/Ytjga/VyuUd+P2 QAUw== X-Gm-Message-State: AOAM530Ga4IoI1DlswTIkyAEqIvaLNViZgbuKSyZUdhaat7s6ivAZezV oAJCcmtZxLbRjsqABzfAJ7K5TDn+3ELYJX7A46MirA== X-Google-Smtp-Source: ABdhPJxx5owWBx3b1CUl8+dsHwfcv0N4UFWJBm3EBtbpVbarbqqVzqrRDi4HH2oGoHcMmLrl2KO11jdURI5j8PiP/5c= X-Received: by 2002:aa7:d803:: with SMTP id v3mr9489359edq.153.1611763990574; Wed, 27 Jan 2021 08:13:10 -0800 (PST) MIME-Version: 1.0 References: <20210126144630.230714-1-pasha.tatashin@soleen.com> <20210126144630.230714-2-pasha.tatashin@soleen.com> In-Reply-To: From: Pavel Tatashin Date: Wed, 27 Jan 2021 11:12:34 -0500 Message-ID: Subject: Re: [PATCH v4 1/1] loop: scale loop device by introducing per device lock To: Jens Axboe Cc: Tyler Hicks , linux-block@vger.kernel.org, LKML , Sasha Levin , James Morris , lukas.bulwahn@gmail.com, hch@lst.de, Petr Vorel , ming.lei@redhat.com, mzxreary@0pointer.de, mcgrof@kernel.org, zhengbin13@huawei.com, maco@android.com, Colin King , evgreen@chromium.org Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jan 26, 2021 at 3:09 PM Jens Axboe wrote: > > On 1/26/21 7:46 AM, Pavel Tatashin wrote: > > Currently, loop device has only one global lock: loop_ctl_mutex. > > > > This becomes hot in scenarios where many loop devices are used. > > > > Scale it by introducing per-device lock: lo_mutex that protects > > modifications of all fields in struct loop_device. > > > > Keep loop_ctl_mutex to protect global data: loop_index_idr, loop_lookup, > > loop_add. > > > > The new lock ordering requirement is that loop_ctl_mutex must be taken > > before lo_mutex. > > Applied, thanks. Great, thank you! Pasha > > -- > Jens Axboe >