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=-4.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS 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 D812FC43381 for ; Sun, 17 Feb 2019 18:49:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B34CD217FA for ; Sun, 17 Feb 2019 18:49:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725767AbfBQStq convert rfc822-to-8bit (ORCPT ); Sun, 17 Feb 2019 13:49:46 -0500 Received: from lithops.sigma-star.at ([195.201.40.130]:50106 "EHLO lithops.sigma-star.at" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725613AbfBQStq (ORCPT ); Sun, 17 Feb 2019 13:49:46 -0500 Received: from localhost (localhost [127.0.0.1]) by lithops.sigma-star.at (Postfix) with ESMTP id 78A3C608A380; Sun, 17 Feb 2019 19:49:43 +0100 (CET) Received: from lithops.sigma-star.at ([127.0.0.1]) by localhost (lithops.sigma-star.at [127.0.0.1]) (amavisd-new, port 10032) with ESMTP id 9ZYEOy4yVhBy; Sun, 17 Feb 2019 19:49:42 +0100 (CET) Received: from localhost (localhost [127.0.0.1]) by lithops.sigma-star.at (Postfix) with ESMTP id 2F911608A390; Sun, 17 Feb 2019 19:49:42 +0100 (CET) Received: from lithops.sigma-star.at ([127.0.0.1]) by localhost (lithops.sigma-star.at [127.0.0.1]) (amavisd-new, port 10026) with ESMTP id pTZOA9BnCreY; Sun, 17 Feb 2019 19:49:42 +0100 (CET) Received: from blindfold.localnet (213-47-184-186.cable.dynamic.surfer.at [213.47.184.186]) by lithops.sigma-star.at (Postfix) with ESMTPSA id D5174608A380; Sun, 17 Feb 2019 19:49:40 +0100 (CET) From: Richard Weinberger To: Sasha Levin Cc: Linus Walleij , Greg Kroah-Hartman , stable@vger.kernel.org, openwrt-devel@lists.openwrt.org, "David S . Miller" , Eric Dumazet , Liping Zhang , John Youn , =?utf-8?B?UmFmYcWCIE1pxYJlY2tp?= , James Hughes , Felix Fietkau , Boris Brezillon Subject: Re: [PATCH 6/8 v3] ubifs: Use dirty_writeback_interval value for wbuf timer Date: Sun, 17 Feb 2019 19:49:39 +0100 Message-ID: <3972784.GJSNoKju5i@blindfold> In-Reply-To: <20190217181802.GH10616@sasha-vm> References: <20190214132403.10687-1-linus.walleij@linaro.org> <20190214132403.10687-7-linus.walleij@linaro.org> <20190217181802.GH10616@sasha-vm> MIME-Version: 1.0 Content-Transfer-Encoding: 8BIT Content-Type: text/plain; charset="UTF-8" Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org Am Sonntag, 17. Februar 2019, 19:18:02 CET schrieb Sasha Levin: > On Thu, Feb 14, 2019 at 02:24:01PM +0100, Linus Walleij wrote: > >From: Rafał Miłecki > > > >commit 1b7fc2c0069f3864a3dda15430b7aded31c0bfcc upstream. > > > >Right now wbuf timer has hardcoded timeouts and there is no place for > >manual adjustments. Some projects / cases many need that though. Few > >file systems allow doing that by respecting dirty_writeback_interval > >that can be set using sysctl (dirty_writeback_centisecs). > > > >Lowering dirty_writeback_interval could be some way of dealing with user > >space apps lacking proper fsyncs. This is definitely *not* a perfect > >solution but we don't have ideal (user space) world. There were already > >advanced discussions on this matter, mostly when ext4 was introduced and > >it wasn't behaving as ext3. Anyway, the final decision was to add some > >hacks to the ext4, as trying to fix whole user space or adding new API > >was pointless. > > > >We can't (and shouldn't?) just follow ext4. We can't e.g. sync on close > >as this would cause too many commits and flash wearing. On the other > >hand we still should allow some trade-off between -o sync and default > >wbuf timeout. Respecting dirty_writeback_interval should allow some sane > >cutomizations if used warily. > > > >Signed-off-by: Rafał Miłecki > >Reviewed-by: Boris Brezillon > >Signed-off-by: Richard Weinberger > >Signed-off-by: Linus Walleij > > This one looks like a new feature that will also require changes to > userspace. Is there actual breakage this fixes? IIRC that's why I never tagged it for -stable. Maybe there is some other odds it fixes and I'm not aware of. Linus? Thanks, //richard