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=-8.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,USER_AGENT_MUTT autolearn=unavailable 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 1D9D3C282C6 for ; Thu, 24 Jan 2019 08:50:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id DD43321872 for ; Thu, 24 Jan 2019 08:50:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726997AbfAXIui (ORCPT ); Thu, 24 Jan 2019 03:50:38 -0500 Received: from mx2.suse.de ([195.135.220.15]:35524 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1725290AbfAXIuh (ORCPT ); Thu, 24 Jan 2019 03:50:37 -0500 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 80F9AAED1; Thu, 24 Jan 2019 08:50:36 +0000 (UTC) Received: by quack2.suse.cz (Postfix, from userid 1000) id B3F5D1E3FF5; Thu, 24 Jan 2019 09:50:35 +0100 (CET) Date: Thu, 24 Jan 2019 09:50:35 +0100 From: Jan Kara To: Kanchan Joshi Cc: linux-fsdevel@vger.kernel.org, linux-block@vger.kernel.org, linux-ext4@vger.kernel.org, linux-nvme@lists.infradead.org, jack@suse.com, david@fromorbit.com, tytso@mit.edu, prakash.v@samsung.com Subject: Re: [PATCH 4/4] fs/ext4,jbd2: add support for passing write-hint with journal. Message-ID: <20190124085035.GC12184@quack2.suse.cz> References: <1547047861-7271-1-git-send-email-joshi.k@samsung.com> <1547047861-7271-5-git-send-email-joshi.k@samsung.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1547047861-7271-5-git-send-email-joshi.k@samsung.com> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-ext4-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-ext4@vger.kernel.org On Wed 09-01-19 21:01:01, Kanchan Joshi wrote: > For NAND based SSDs, mixing of data with different life-time reduces > efficiency of internal garbage-collection. During FS operations, series > of journal updates will follow/precede series of data/meta updates, causing > intermixing inside SSD. By passing a write-hint with journal, its write > can be isolated from other data/meta writes, leading to endurance/performance > benefit on SSD. > > This patch introduces "j_writehint" member in JBD2 journal, using which > Ext4 specifies write-hint (as SHORT) for journal. > > Signed-off-by: Kanchan Joshi Thanks for the patch. It looks mostly good, just one nit below. > diff --git a/fs/ext4/super.c b/fs/ext4/super.c > index d6c142d..3af4049 100644 > --- a/fs/ext4/super.c > +++ b/fs/ext4/super.c > @@ -4289,6 +4289,8 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent) > > set_task_ioprio(sbi->s_journal->j_task, journal_ioprio); > > + sbi->s_journal->j_writehint = KERN_WRITE_LIFE_SHORT; > + > sbi->s_journal->j_commit_callback = ext4_journal_commit_callback; So I'd rather have defines like: #define EXT4_WRITE_HINT_JOURNAL KERN_WRITE_HINT_MIN like I suggested in another email and then later we could add stuff like #define EXT4_WRITE_HINT_BITMAP (KERN_WRITE_HINT_MIN + 1) etc. Honza -- Jan Kara SUSE Labs, CR