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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id CFCE7C05027 for ; Thu, 2 Feb 2023 18:12:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231482AbjBBSMy (ORCPT ); Thu, 2 Feb 2023 13:12:54 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52314 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229726AbjBBSMv (ORCPT ); Thu, 2 Feb 2023 13:12:51 -0500 Received: from mail-qv1-xf35.google.com (mail-qv1-xf35.google.com [IPv6:2607:f8b0:4864:20::f35]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0D3336DB24; Thu, 2 Feb 2023 10:12:51 -0800 (PST) Received: by mail-qv1-xf35.google.com with SMTP id q10so1460003qvt.10; Thu, 02 Feb 2023 10:12:51 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:from:to:cc:subject:date:message-id:reply-to; bh=Vu2PIhqwB/jA5g6/FKXtK5UWNVrTlqF+m2/SNkuST3g=; b=faARiKxCZLzQbjD1qCCn6AklBNIT8mmv9blF5BevytlDpR1uj1tE8NO1fUZV+v5WTS J2uog8kc0KVMNGjE/zid1sFqF+luQBj6/lh9P6nRZrMAUz7TewfNzCo2/RbmKT1OK6ur wh5JxUjPNJL3xyaaEmV8eWeH/NXrykleEamy///m7ZhyVvFm5DwmD8nAXmTOSx6pNzsf CyXc268LHFZ6bOJv9QfAjsu3RqLx32qO8W0G1hyA/sIlH6B9KDFof0SaeUPTZOnfJCWL ZBbYcu3EPHWDoM9Unkhiq5Emrb+g40JMADDUD72Fdn5FMW79/AC5gJ8eF8bGy8cnvAi6 Q6/g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=Vu2PIhqwB/jA5g6/FKXtK5UWNVrTlqF+m2/SNkuST3g=; b=eaEaUPI51gfISBKF36hNslFp0uTPANX43l+UdQyhstdJEzxU2VhOAWZ9yyOF7ZyFVI 0ohnRYAn8foSi0+vX786mQXPfB7Rfp7vbJZC7qNi6boKFIB69VGWBoJMRiPWH5VqGgZj bc3lip8e+tviF1OwRjubmCKBt7mpUfCSQuBrtF6/x6nRNp/xhTQwZWjhI+xxtacIZ5Nh UmhpNiOY+QSJmiMgekwogyPl0k5Vjxn8iCNzRNcz82atyxxHSastHlarQu0sSW82YiZI fkZFf27HaVNwVUcvF/rF9un7dnP4c6sXDM9X4szUr8rpp7P7XLG2u9k6jxsAYH7AQLvY 4S1A== X-Gm-Message-State: AO0yUKVd6H+mhGIatPHw+ytvmoperD1F7ZQ8miNfKGAVhhiKdfEY3Zvo LaluMDKscCydznlQ/imfsThVFMVh2fJfXcQl07Y= X-Google-Smtp-Source: AK7set8+ZIkl+bDv+TJMe38gRihkPFyCuXiMu+1Eel893PNKyOjjWb5MRcTIoJ1aRPPe4HVRC+Xvu15N4meyWWj/JuA= X-Received: by 2002:a05:6214:a44:b0:537:7f85:22b7 with SMTP id ee4-20020a0562140a4400b005377f8522b7mr476625qvb.77.1675361570130; Thu, 02 Feb 2023 10:12:50 -0800 (PST) MIME-Version: 1.0 References: <20230126051657.163497-1-huijin.park@samsung.com> <20230126053136.GC28355@lst.de> In-Reply-To: <20230126053136.GC28355@lst.de> From: Huijin Park Date: Fri, 3 Feb 2023 03:12:41 +0900 Message-ID: Subject: Re: [PATCH] loop: change fsync to fdatasync when update dio To: Christoph Hellwig Cc: Huijin Park , Jens Axboe , Chaitanya Kulkarni , linux-block@vger.kernel.org, linux-kernel@vger.kernel.org Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jan 26, 2023 at 2:31 PM Christoph Hellwig wrote: > > On Thu, Jan 26, 2023 at 02:16:57PM +0900, Huijin Park wrote: > > In general, fsync has a larger overhead than fdatasync. And since the > > dio option is for data, it seems like fdatasync is enough. > > So this patch changes it to fdatasync which has little load relatively. > > The only difference is that fsync also syncs the timestamps. So this > change looks correct, but also a bit useless given that buffered to > direct I/O or back changes aren't exactly a fast path. Although the difference will be minimal, why I suggested it is because it can reduce unnecessary metadata i/o (helpful on slow i/o devices), and using fdatasync looked correct like your opinion. In some environment cases, loop setup for mount is required when application is initialized and this change will help.