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=-8.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 BACCAC43381 for ; Tue, 26 Jan 2021 17:17:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8EA45230FE for ; Tue, 26 Jan 2021 17:17:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389518AbhAZRO4 (ORCPT ); Tue, 26 Jan 2021 12:14:56 -0500 Received: from mx2.suse.de ([195.135.220.15]:35800 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2390989AbhAZJZB (ORCPT ); Tue, 26 Jan 2021 04:25:01 -0500 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 6E458AC4F; Tue, 26 Jan 2021 09:24:19 +0000 (UTC) Date: Tue, 26 Jan 2021 10:24:16 +0100 From: Petr Vorel To: Pavel Tatashin Cc: tyhicks@linux.microsoft.com, axboe@kernel.dk, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, sashal@kernel.org, jmorris@namei.org, lukas.bulwahn@gmail.com, hch@lst.de, ming.lei@redhat.com, mzxreary@0pointer.de, mcgrof@kernel.org, zhengbin13@huawei.com, maco@android.com, colin.king@canonical.com, evgreen@chromium.org Subject: Re: [PATCH v3 1/1] loop: scale loop device by introducing per device lock Message-ID: Reply-To: Petr Vorel References: <20210125201156.1330164-1-pasha.tatashin@soleen.com> <20210125201156.1330164-2-pasha.tatashin@soleen.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210125201156.1330164-2-pasha.tatashin@soleen.com> Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org Hi, > 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 the > fields in struct loop_device. Keep loop_ctl_mutex to protect global > data such as loop_index_idr, loop_lookup, loop_add. > Lock ordering: loop_ctl_mutex > lo_mutex. Reviewed-by: Petr Vorel Kind regards, Petr