From mboxrd@z Thu Jan 1 00:00:00 1970 From: Hyunchul Lee Subject: Re: [RFC PATCH 0/2] apply write hints to select the type of segments Date: Mon, 13 Nov 2017 09:24:55 +0900 Message-ID: <5A08E657.8060807@gmail.com> References: <1510206688-12767-1-git-send-email-hyc.lee@gmail.com> <1b0b44de-c724-5dc4-e9cb-79a894bdb611@huawei.com> <5A04F184.3000204@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from sfi-mx-4.v28.ch3.sourceforge.com ([172.29.28.194] helo=mx.sourceforge.net) by sfs-ml-3.v29.ch3.sourceforge.com with esmtps (TLSv1.2:ECDHE-RSA-AES256-GCM-SHA384:256) (Exim 4.89) (envelope-from ) id 1eE2Yj-0005vd-84 for linux-f2fs-devel@lists.sourceforge.net; Mon, 13 Nov 2017 00:25:05 +0000 Received: from lgeamrelo12.lge.com ([156.147.23.52]) by sfi-mx-4.v28.ch3.sourceforge.com with esmtp (Exim 4.89) id 1eE2Yh-0007aU-21 for linux-f2fs-devel@lists.sourceforge.net; Mon, 13 Nov 2017 00:25:05 +0000 In-Reply-To: List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: linux-f2fs-devel-bounces@lists.sourceforge.net To: Chao Yu Cc: kernel-team@lge.com, Jaegeuk Kim , Hyunchul Lee , linux-kernel@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net On 11/10/2017 03:42 PM, Chao Yu wrote: > On 2017/11/10 8:23, Hyunchul Lee wrote: >> Hello, Chao >> >> On 11/09/2017 06:12 PM, 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? >>> >> >> I am afraid that this makes side effects. for example, this could cause >> out-of-place updates even when there are not enough free segments. >> I can write the patch that handles these situations. But I wonder >> that this is required, and I am not sure which IPU polices can be disabled. > > Oh, As I replied in another thread, I think IPU just affects filesystem > hot/cold separating, rather than this feature. So I think it will be okay > to not consider it. > >> >>>> >>>> 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") >>> >> >> Sure I will. I wrote it already ;) > > Cool, ;) > >> I think that datas from the same segment should be passed down with the same >> hint, and the following mapping is reasonable. I wonder what is your opinion >> about it. >> >> segment type hints >> ------------ ----- >> CURSEG_COLD_DATA WRITE_LIFE_EXTREME >> CURSEG_HOT_DATA WRITE_LIFE_SHORT >> CURSEG_COLD_NODE WRITE_LIFE_NORMAL > > We have WRITE_LIFE_LONG defined rather than WRITE_LIFE_NORMAL in fs.h? > >> CURSEG_HOT_NODE WRITE_LIFE_MEDIUM > > As I know, in scenario of cell phone, data of meta_inode is hottest, then hot > data, warm node, and cold node should be coldest. So I suggested we can define > as below: > > META_DATA WRITE_LIFE_SHORT > HOT_DATA & WARM_NODE WRITE_LIFE_MEDIUM > HOT_NODE & WARM_DATA WRITE_LIFE_LONG > COLD_NODE & COLD_DATA WRITE_LIFE_EXTREME > I agree, But I am not sure that assigning the same hint to a node and data segment is good. Because NVMe is likely to write them in the same erase block if they have the same hint. Thanks. > Thanks, > >> others WRITE_LIFE_NONE >> >>> 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(-) >>>> >>> >>> >> >> Thanks >> >> . >> > > ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, Slashdot.org! http://sdm.link/slashdot From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751526AbdKMAY7 (ORCPT ); Sun, 12 Nov 2017 19:24:59 -0500 Received: from LGEAMRELO12.lge.com ([156.147.23.52]:37155 "EHLO lgeamrelo12.lge.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751462AbdKMAY5 (ORCPT ); Sun, 12 Nov 2017 19:24:57 -0500 X-Original-SENDERIP: 156.147.1.125 X-Original-MAILFROM: hyc.lee@gmail.com X-Original-SENDERIP: 10.177.225.35 X-Original-MAILFROM: hyc.lee@gmail.com Message-ID: <5A08E657.8060807@gmail.com> Date: Mon, 13 Nov 2017 09:24:55 +0900 From: Hyunchul Lee User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.3.0 MIME-Version: 1.0 To: Chao Yu CC: Jaegeuk Kim , 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 References: <1510206688-12767-1-git-send-email-hyc.lee@gmail.com> <1b0b44de-c724-5dc4-e9cb-79a894bdb611@huawei.com> <5A04F184.3000204@gmail.com> In-Reply-To: Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 11/10/2017 03:42 PM, Chao Yu wrote: > On 2017/11/10 8:23, Hyunchul Lee wrote: >> Hello, Chao >> >> On 11/09/2017 06:12 PM, 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? >>> >> >> I am afraid that this makes side effects. for example, this could cause >> out-of-place updates even when there are not enough free segments. >> I can write the patch that handles these situations. But I wonder >> that this is required, and I am not sure which IPU polices can be disabled. > > Oh, As I replied in another thread, I think IPU just affects filesystem > hot/cold separating, rather than this feature. So I think it will be okay > to not consider it. > >> >>>> >>>> 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") >>> >> >> Sure I will. I wrote it already ;) > > Cool, ;) > >> I think that datas from the same segment should be passed down with the same >> hint, and the following mapping is reasonable. I wonder what is your opinion >> about it. >> >> segment type hints >> ------------ ----- >> CURSEG_COLD_DATA WRITE_LIFE_EXTREME >> CURSEG_HOT_DATA WRITE_LIFE_SHORT >> CURSEG_COLD_NODE WRITE_LIFE_NORMAL > > We have WRITE_LIFE_LONG defined rather than WRITE_LIFE_NORMAL in fs.h? > >> CURSEG_HOT_NODE WRITE_LIFE_MEDIUM > > As I know, in scenario of cell phone, data of meta_inode is hottest, then hot > data, warm node, and cold node should be coldest. So I suggested we can define > as below: > > META_DATA WRITE_LIFE_SHORT > HOT_DATA & WARM_NODE WRITE_LIFE_MEDIUM > HOT_NODE & WARM_DATA WRITE_LIFE_LONG > COLD_NODE & COLD_DATA WRITE_LIFE_EXTREME > I agree, But I am not sure that assigning the same hint to a node and data segment is good. Because NVMe is likely to write them in the same erase block if they have the same hint. Thanks. > Thanks, > >> others WRITE_LIFE_NONE >> >>> 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(-) >>>> >>> >>> >> >> Thanks >> >> . >> > >