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=-0.7 required=3.0 tests=FREEMAIL_FORGED_FROMDOMAIN, FREEMAIL_FROM,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS 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 33446ECE59D for ; Wed, 16 Oct 2019 02:27:04 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id C6F7920854 for ; Wed, 16 Oct 2019 02:27:03 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org C6F7920854 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=sina.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 2F27C8E0005; Tue, 15 Oct 2019 22:27:03 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 2A3298E0001; Tue, 15 Oct 2019 22:27:03 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 1BAE98E0005; Tue, 15 Oct 2019 22:27:03 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0153.hostedemail.com [216.40.44.153]) by kanga.kvack.org (Postfix) with ESMTP id EE2F48E0001 for ; Tue, 15 Oct 2019 22:27:02 -0400 (EDT) Received: from smtpin21.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with SMTP id 983BC180295A0 for ; Wed, 16 Oct 2019 02:27:02 +0000 (UTC) X-FDA: 76048060284.21.man97_7782588727f3d X-HE-Tag: man97_7782588727f3d X-Filterd-Recvd-Size: 1845 Received: from r3-24.sinamail.sina.com.cn (r3-24.sinamail.sina.com.cn [202.108.3.24]) by imf37.hostedemail.com (Postfix) with SMTP for ; Wed, 16 Oct 2019 02:27:00 +0000 (UTC) Received: from unknown (HELO localhost.localdomain)([114.253.230.207]) by sina.com with ESMTP id 5DA67FEF00031507; Wed, 16 Oct 2019 10:26:57 +0800 (CST) X-Sender: hdanton@sina.com X-Auth-ID: hdanton@sina.com X-SMAIL-MID: 76932954919912 From: Hillf Danton To: Tejun Heo Cc: Hillf Danton , Jan Kara , mm , fsdev , Andrew Morton , linux , Roman Gushchin , Johannes Weiner , Shakeel Butt , Fengguang Wu , Minchan Kim , Mel Gorman Subject: Re: [RFC] writeback: add elastic bdi in cgwb bdp Date: Wed, 16 Oct 2019 10:26:46 +0800 Message-Id: <20191016022646.12992-1-hdanton@sina.com> In-Reply-To: <20191015140356.9256-1-hdanton@sina.com> References: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Bogosity: Ham, tests=bogofilter, spamicity=0.000001, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: Hello Tejun On Tue, 15 Oct 2019 07:37:31 -0700 Tejun Heo wrote: > Hello, Hillf. >=20 > Do you have a test case which can demonstrate the problem you're > seeing in the existing code? I dont have such a test case because I see no problem in the current bw measurings except for the difficulties. For example, wb-A's bw is measured to be 66MB/s if wb-B joins it dispatching IO, or 96MB/s if wb-C also joins them, in assumption it is a simple case. It may be too difficult to be feasible, I am afraid, to get wb-A's bw under the workloads in data centers without wb-non-A's churnings. Thanks Hillf