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=-0.9 required=3.0 tests=DKIMWL_WL_HIGH,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 336CDC3A589 for ; Thu, 15 Aug 2019 14:50:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id F204E2067D for ; Thu, 15 Aug 2019 14:50:11 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=android.com header.i=@android.com header.b="SFv3m91M" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731715AbfHOOuL (ORCPT ); Thu, 15 Aug 2019 10:50:11 -0400 Received: from mail-lj1-f194.google.com ([209.85.208.194]:36473 "EHLO mail-lj1-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729909AbfHOOuL (ORCPT ); Thu, 15 Aug 2019 10:50:11 -0400 Received: by mail-lj1-f194.google.com with SMTP id u15so2482596ljl.3 for ; Thu, 15 Aug 2019 07:50:09 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=android.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=JYT2OSHdO2DhGI1fwQFHGoFCd1oy7Hq2Yne9sDtdOm8=; b=SFv3m91M3bw6JeMwDStZK9fHM0zPXfPmHV+zj7XOFgng2BkLQhXyTBN+CDlDyE3tE+ pJYRl0W5IoisMmUL3u7KLavEtBV8WbsayMKI2Ndj7PpuPn1m/sYhPMWdV3hvRDwf7U2d W2r62kWw8X9sgxRVC+sHMOJrk2mP8bbSHWARbLYevcM4vkV/a9IZuCwt9svHaU72eNYg f37aWSotRPlDW6ZHMaPfJWofSRQCKFiPXOs3wTJ2ZGvu35ErDBW5VN69RYP5Ke8IbTHb ihrcejBWCucjoAABUL2XgxJ8VCzXm6zX+46m1qzRBmD10PQ0H9C/UYl+cRKw15fVUYIX RXBw== 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=JYT2OSHdO2DhGI1fwQFHGoFCd1oy7Hq2Yne9sDtdOm8=; b=sVZilKKL/hiqv4DShlQ9CoM+jKTuEYRrppkH6s1ZONxWPuqHENkm1zm/2a7C2SLfe8 h8uSLu7sdHnx1WgF/2BLD6rlKlt2Hm07AL1GMtpEmZu7YiGLPSl7LQUIDb9a4fxKOPse A0iOhsRooWmt1+opZf9/+/172HbrsOj6ToOxlaeemdLd2/j0juMZtPJfoBou9+CJOOfc lp3gZVVnlG40YJNu7HI1x8JvbaPSkPatBn5tV6+gv1Fysx+pDTMxcgrsdIKFr0EtvGDU EKmIE9aH0ufU1wR4sAxklpf9fiJAUup90ukufYbuPvwaZjqYRXIfIjmt5TrtP2BhBU5D B9XQ== X-Gm-Message-State: APjAAAXpRNm1BTutQGaYT5YNKpLnv/1UYgNIZRheCrt5dIBhjHQl8xXM wZsCeRvjptEkY97Bj3rsXEEBvSFu8jQKJr3FxAQtqQ== X-Google-Smtp-Source: APXvYqyfs8OtHgp4GrtWZwMaMMg8hiNezGefnRigGy1I7CavN0aKhlm20eEzQ6pzBIanR2L4TTIMz54bjUdmC6/qSH0= X-Received: by 2002:a2e:96d3:: with SMTP id d19mr613083ljj.185.1565880609143; Thu, 15 Aug 2019 07:50:09 -0700 (PDT) MIME-Version: 1.0 References: <20190814103244.92518-1-maco@android.com> <29990045-b05e-1411-a5c2-32e735265a04@acm.org> In-Reply-To: <29990045-b05e-1411-a5c2-32e735265a04@acm.org> From: Martijn Coenen Date: Thu, 15 Aug 2019 15:49:58 +0100 Message-ID: Subject: Re: [PATCH] RFC: loop: Avoid calling blk_mq_freeze_queue() when possible. To: Bart Van Assche Cc: axboe@kernel.dk, linux-block@vger.kernel.org, LKML , Greg KH , kernel-team@android.com, Narayan Kamath , Dario Freni , Nikita Ioffe , Jiyong Park , Martijn Coenen Content-Type: text/plain; charset="UTF-8" Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On Wed, Aug 14, 2019 at 4:29 PM Bart Van Assche wrote: > Hi Martijn, > > Is the loop driver used in Android Q to make a file on a filesystem > visible as a block device or rather to make a subset of a block device > visible as a block device? In the latter case, have you considered to > use the dm-linear driver instead? I expect that the overhead per I/O of > dm-linear will be lower than that of the loop driver. Hi Bart, In this case we're using the loop driver to make a file on the filesystem visible as a block device (in the file is a filesystem we want to mount), so unfortunately dm-linear is not an option. Best, Martijn > > Bart.