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=-12.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,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 E613FC04AB4 for ; Tue, 14 May 2019 08:29:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C06F820675 for ; Tue, 14 May 2019 08:29:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726605AbfENI34 (ORCPT ); Tue, 14 May 2019 04:29:56 -0400 Received: from szxga02-in.huawei.com ([45.249.212.188]:3009 "EHLO huawei.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726109AbfENI34 (ORCPT ); Tue, 14 May 2019 04:29:56 -0400 Received: from DGGEMM402-HUB.china.huawei.com (unknown [172.30.72.55]) by Forcepoint Email with ESMTP id 2A642CAC562BAF98E832; Tue, 14 May 2019 16:29:54 +0800 (CST) Received: from dggeme763-chm.china.huawei.com (10.3.19.109) by DGGEMM402-HUB.china.huawei.com (10.3.20.210) with Microsoft SMTP Server (TLS) id 14.3.439.0; Tue, 14 May 2019 16:29:53 +0800 Received: from [10.134.22.195] (10.134.22.195) by dggeme763-chm.china.huawei.com (10.3.19.109) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.1591.10; Tue, 14 May 2019 16:29:53 +0800 Subject: Re: [f2fs-dev] [PATCH] f2fs: issue discard commands proactively in high fs utilization To: Ju Hyung Park , Jaegeuk Kim , Chao Yu CC: , References: <20180529205048.39694-1-jaegeuk@kernel.org> From: Chao Yu Message-ID: <73fc6da8-7b89-3b02-8856-bd6876c50259@huawei.com> Date: Tue, 14 May 2019 16:29:32 +0800 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset="windows-1252" Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [10.134.22.195] X-ClientProxiedBy: dggeme711-chm.china.huawei.com (10.1.199.107) To dggeme763-chm.china.huawei.com (10.3.19.109) X-CFilter-Loop: Reflected Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2019/5/14 13:39, Ju Hyung Park wrote: > On Wed, May 30, 2018 at 5:51 AM Jaegeuk Kim wrote: >> >> In the high utilization like over 80%, we don't expect huge # of large discard >> commands, but do many small pending discards which affects FTL GCs a lot. >> Let's issue them in that case. >> >> Signed-off-by: Jaegeuk Kim >> --- >> diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c >> index 6e40e536dae0..8c1f7a6bf178 100644 >> --- a/fs/f2fs/segment.c >> +++ b/fs/f2fs/segment.c >> @@ -915,6 +915,38 @@ static void __check_sit_bitmap(struct f2fs_sb_info *sbi, >> + dpolicy->max_interval = DEF_MIN_DISCARD_ISSUE_TIME; > > Isn't this way too aggressive? > > Discard thread will wake up on 50ms interval just because the user has > used 80% of space. > 60,000ms vs 50ms is too much of a stark difference. > > I feel something like 10 seconds(10,000ms) could be a much more > reasonable choice than this. Hmm.. I agree that current hard code method is not flexible enough, and I proposed below patch last year to adjust interval according to space usage, it looks Jaegeuk partially agreed with that, and pointed out we need to distinguish low/high-end storage to decide interval. And also you point out that btrfs introduces mount option "ssd" to let user give the device type, and we can distinguish with that. :P https://git.kernel.org/pub/scm/linux/kernel/git/chao/linux.git/commit/?h=f2fs-dev&id=009f548e37ca5d9b4cad9e3c15c2164c53eff1df But I pended below patch based on Jaegeuk's and your idea due to other work... https://git.kernel.org/pub/scm/linux/kernel/git/chao/linux.git/commit/?h=f2fs-dev&id=47a992c12398c98e739e3eedc2743824459df943 Thanks, > > Thanks. > > > _______________________________________________ > Linux-f2fs-devel mailing list > Linux-f2fs-devel@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel > . >