From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754093AbdKIJN2 (ORCPT ); Thu, 9 Nov 2017 04:13:28 -0500 Received: from szxga04-in.huawei.com ([45.249.212.190]:10422 "EHLO szxga04-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753712AbdKIJNU (ORCPT ); Thu, 9 Nov 2017 04:13:20 -0500 Subject: Re: [RFC PATCH 0/2] apply write hints to select the type of segments To: Hyunchul Lee , Jaegeuk Kim CC: , , , Hyunchul Lee , Chao Yu References: <1510206688-12767-1-git-send-email-hyc.lee@gmail.com> From: Chao Yu Message-ID: <1b0b44de-c724-5dc4-e9cb-79a894bdb611@huawei.com> Date: Thu, 9 Nov 2017 17:12:57 +0800 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:52.0) Gecko/20100101 Thunderbird/52.3.0 MIME-Version: 1.0 In-Reply-To: <1510206688-12767-1-git-send-email-hyc.lee@gmail.com> Content-Type: text/plain; charset="windows-1252" Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [10.134.22.195] X-CFilter-Loop: Reflected X-Mirapoint-Virus-RAPID-Raw: score=unknown(0), refid=str=0001.0A020205.5A041C1D.0050,ss=1,re=0.000,recu=0.000,reip=0.000,cl=1,cld=1,fgs=0, ip=0.0.0.0, so=2014-11-16 11:51:01, dmn=2013-03-21 17:37:32 X-Mirapoint-Loop-Id: fbdda3274ddde6add37b38ab024b88ea Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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? > > 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(-) >