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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id DB5E9C433F5 for ; Tue, 1 Mar 2022 15:05:59 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 008F08D0002; Tue, 1 Mar 2022 10:05:59 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id ED3F58D0001; Tue, 1 Mar 2022 10:05:58 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id D75A18D0002; Tue, 1 Mar 2022 10:05:58 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (relay.hostedemail.com [64.99.140.25]) by kanga.kvack.org (Postfix) with ESMTP id C2C7B8D0001 for ; Tue, 1 Mar 2022 10:05:58 -0500 (EST) Received: from smtpin05.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay08.hostedemail.com (Postfix) with ESMTP id 7E4C821B38 for ; Tue, 1 Mar 2022 15:05:58 +0000 (UTC) X-FDA: 79196142396.05.ED2AD34 Received: from lithops.sigma-star.at (lithops.sigma-star.at [195.201.40.130]) by imf27.hostedemail.com (Postfix) with ESMTP id 86D4640002 for ; Tue, 1 Mar 2022 15:05:57 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by lithops.sigma-star.at (Postfix) with ESMTP id B0E44609B3C0; Tue, 1 Mar 2022 16:05:55 +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 0v40nSVbi-hE; Tue, 1 Mar 2022 16:05:55 +0100 (CET) Received: from localhost (localhost [127.0.0.1]) by lithops.sigma-star.at (Postfix) with ESMTP id 33003609B3D3; Tue, 1 Mar 2022 16:05:55 +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 Kz-2b_1qeBCK; Tue, 1 Mar 2022 16:05:55 +0100 (CET) Received: from lithops.sigma-star.at (lithops.sigma-star.at [195.201.40.130]) by lithops.sigma-star.at (Postfix) with ESMTP id F2CA5609B3C0; Tue, 1 Mar 2022 16:05:54 +0100 (CET) Date: Tue, 1 Mar 2022 16:05:54 +0100 (CET) From: Richard Weinberger To: Jan Kara Cc: wuchi zero , =?utf-8?Q?Rafa=C5=82_Mi=C5=82ecki?= , tj , mszeredi , sedat dilek , axboe , Andrew Morton , torvalds , linux-mm , linux-mtd , linux-fsdevel , linux-kernel Message-ID: <719960584.100772.1646147154879.JavaMail.zimbra@nod.at> In-Reply-To: <20220301103218.ulbmakdy4gbw2fso@quack3.lan> References: <2104629126.100059.1646129517209.JavaMail.zimbra@nod.at> <20220301103218.ulbmakdy4gbw2fso@quack3.lan> Subject: Re: Different writeback timing since v5.14 MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable X-Originating-IP: [195.201.40.130] X-Mailer: Zimbra 8.8.12_GA_3807 (ZimbraWebClient - FF97 (Linux)/8.8.12_GA_3809) Thread-Topic: Different writeback timing since v5.14 Thread-Index: A7tsGqUsSQ3AY4M1uWfsU/0uR9rf+A== X-Rspam-User: X-Rspamd-Server: rspam02 X-Rspamd-Queue-Id: 86D4640002 X-Stat-Signature: dc5fqz63wmhkhkc99mac3bxe4ej7oimm Authentication-Results: imf27.hostedemail.com; dkim=none; dmarc=none; spf=pass (imf27.hostedemail.com: domain of richard@nod.at designates 195.201.40.130 as permitted sender) smtp.mailfrom=richard@nod.at X-HE-Tag: 1646147157-822871 X-Bogosity: Ham, tests=bogofilter, spamicity=0.001122, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: Jan, ----- Urspr=C3=BCngliche Mail ----- > Von: "Jan Kara" >> Is this expected? >> Just want to make sure that the said commit didn't uncover an UBIFS issu= e. >=20 > Yes, I think it is expected. Likely the background threshold for UBIFS bd= i > is very small (probably UBIFS is not used much for writeback compared to > other filesystems). Previously, we just used wb_stat() which returned 0 > (PCP counter inexact value) and so background writeback didn't trigger. N= ow > we use wb_stat_sum() when threshold is small, get exact value of dirty > pages and decide to start background writeback. Thanks for the prompt reply! > The only thing is, whether it is really expected that the threshold for > UBIFS bdi is so small. You can check the values in > /sys/kernel/debug/bdi//stats. BdiDirtyThresh is indeed 0. BdiWriteback: 0 kB BdiReclaimable: 0 kB BdiDirtyThresh: 0 kB DirtyThresh: 772620 kB BackgroundThresh: 385836 kB BdiDirtied: 0 kB BdiWritten: 0 kB BdiWriteBandwidth: 102400 kBps b_dirty: 0 b_io: 0 b_more_io: 0 b_dirty_time: 0 bdi_list: 1 state: 1 Thanks, //richard