From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753805AbdKISQ3 (ORCPT ); Thu, 9 Nov 2017 13:16:29 -0500 Received: from mail.kernel.org ([198.145.29.99]:51722 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752730AbdKISQ1 (ORCPT ); Thu, 9 Nov 2017 13:16:27 -0500 DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 20E08214EE Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=jaegeuk@kernel.org Date: Thu, 9 Nov 2017 10:16:24 -0800 From: Jaegeuk Kim To: Chao Yu Cc: Hyunchul Lee , linux-f2fs-devel@lists.sourceforge.net, linux-kernel@vger.kernel.org, kernel-team@lge.com, Hyunchul Lee Subject: Re: [RFC PATCH 0/2] apply write hints to select the type of segments Message-ID: <20171109181624.GA59398@jaegeuk-macbookpro.roam.corp.google.com> References: <1510206688-12767-1-git-send-email-hyc.lee@gmail.com> <1b0b44de-c724-5dc4-e9cb-79a894bdb611@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1b0b44de-c724-5dc4-e9cb-79a894bdb611@huawei.com> User-Agent: Mutt/1.8.2 (2017-04-18) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 11/09, Chao Yu wrote: > On 2017/11/9 13:51, Hyunchul Lee wrote: > > From: Hyunchul Lee > > > > Using write hints[1], applications can inform the life time of the data > > written to devices. and this[2] reported that the write hints patch > > decreased writes in NAND by 25%. > > > > This hints help F2FS to determine the followings. > > 1) the segment types where the data will be written. > > 2) the hints that will be passed down to devices with the data of segments. > > > > This patch set implements the first mapping from write hints to segment types > > as shown below. > > > > hints segment type > > ----- ------------ > > WRITE_LIFE_SHORT CURSEG_COLD_DATA > > WRITE_LIFE_EXTREME CURSEG_HOT_DATA > > others CURSEG_WARM_DATA > > > > The F2FS poliy for hot/cold seperation has precedence over this hints, And > > hints are not applied in in-place update. > > Could we change to disable IPU if file/inode write hint is existing? Well, this is a hint which is not related to IPU. I think user should be aware of controlling IPU. > > > > Before the second mapping is implemented, write hints are not passed down > > to devices. Because it is better that the data of a segment have the same > > hint. > > > > [1]: c75b1d9421f80f4143e389d2d50ddfc8a28c8c35 > > [2]: https://lwn.net/Articles/726477/ > > Could you write a patch to support passing write hint to block layer for > buffered writes as below commit: > 0127251c45ae ("ext4: add support for passing in write hints for buffered writes") > > Thanks, > > > > > Hyunchul Lee (2): > > f2fs: apply write hints to select the type of segments for buffered > > write > > f2fs: apply write hints to select the type of segment for direct write > > > > fs/f2fs/data.c | 101 ++++++++++++++++++++++++++++++++---------------------- > > fs/f2fs/f2fs.h | 1 + > > fs/f2fs/segment.c | 14 +++++++- > > 3 files changed, 74 insertions(+), 42 deletions(-) > >