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=-5.4 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 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 A97B1C433DB for ; Mon, 18 Jan 2021 08:52:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6F87D22211 for ; Mon, 18 Jan 2021 08:52:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387905AbhARIwO (ORCPT ); Mon, 18 Jan 2021 03:52:14 -0500 Received: from szxga07-in.huawei.com ([45.249.212.35]:11399 "EHLO szxga07-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2387859AbhARIwD (ORCPT ); Mon, 18 Jan 2021 03:52:03 -0500 Received: from DGGEMS404-HUB.china.huawei.com (unknown [172.30.72.58]) by szxga07-in.huawei.com (SkyGuard) with ESMTP id 4DK58D17M7z7Wmk; Mon, 18 Jan 2021 16:50:04 +0800 (CST) Received: from [10.136.110.154] (10.136.110.154) by smtp.huawei.com (10.3.19.204) with Microsoft SMTP Server (TLS) id 14.3.498.0; Mon, 18 Jan 2021 16:51:03 +0800 Subject: Re: [f2fs-dev] [PATCH v3 1/2] f2fs: introduce checkpoint=merge mount option To: Daeho Jeong , , , CC: Sungjong Seo , Daeho Jeong References: <20210116010041.3754050-1-daeho43@gmail.com> From: Chao Yu Message-ID: <74067d6f-45f8-3c08-1829-828a1aebddee@huawei.com> Date: Mon, 18 Jan 2021 16:51:03 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: <20210116010041.3754050-1-daeho43@gmail.com> Content-Type: text/plain; charset="windows-1252"; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [10.136.110.154] X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2021/1/16 9:00, Daeho Jeong wrote: > From: Daeho Jeong > > We've added a new mount option "checkpoint=merge", which creates a > kernel daemon and makes it to merge concurrent checkpoint requests as > much as possible to eliminate redundant checkpoint issues. Plus, we > can eliminate the sluggish issue caused by slow checkpoint operation > when the checkpoint is done in a process context in a cgroup having > low i/o budget and cpu shares, and The below verification result > explains this. Could you please summary and add below info into commit message and f2fs.rst? "Actually, the default I/O priority of kernel thread is "4". So, we're going to raise this priority by one, because we want to give one higher priority for checkpointing thread than other normal threads. This is the same way to give a I/O priority to the jbd2 journaling thread of ext4 filesystem." Otherwise this patch looks good to me. Thanks,