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=-5.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 autolearn=no 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 C87C0C433B4 for ; Fri, 16 Apr 2021 03:55:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9EC8C61153 for ; Fri, 16 Apr 2021 03:55:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238350AbhDPD4D (ORCPT ); Thu, 15 Apr 2021 23:56:03 -0400 Received: from mx2.suse.de ([195.135.220.15]:53322 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234659AbhDPD4C (ORCPT ); Thu, 15 Apr 2021 23:56:02 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 7738AAFD5; Fri, 16 Apr 2021 03:55:37 +0000 (UTC) Subject: Re: [PATCH 00/13] bcache patches for Linux v5.13 -- 2nd wave To: axboe@kernel.dk Cc: linux-bcache@vger.kernel.org, linux-block@vger.kernel.org, jianpeng.ma@intel.com, qiaowei.ren@intel.com References: <20210414054648.24098-1-colyli@suse.de> From: Coly Li Message-ID: Date: Fri, 16 Apr 2021 11:55:33 +0800 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:78.0) Gecko/20100101 Thunderbird/78.9.1 MIME-Version: 1.0 In-Reply-To: <20210414054648.24098-1-colyli@suse.de> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On 4/14/21 1:46 PM, Coly Li wrote: > Hi Jens, > > This is the 2nd wave of bcache patches for Linux v5.13. This series are > patches to use NVDIMM to store bcache journal, which is the first effort > to support NVDIMM for bcache [EXPERIMENTAL]. > > All concerns from Linux v5.12 merge window are fixed, especially the > data type defined in include/uapi/linux/bcache-nvm.h. And in this > series, all the lists defined in bcache-nvm.h uapi file are stored and > accessed directly on NVDIMM as memory objects. > > Intel developers Jianpeng Ma and Qiaowei Ren compose the initial code of > nvm-pages, the related patches are, > - bcache: initialize the nvm pages allocator > - bcache: initialization of the buddy > - bcache: bch_nvm_alloc_pages() of the buddy > - bcache: bch_nvm_free_pages() of the buddy > - bcache: get allocated pages from specific owner > All the code depends on Linux libnvdimm and dax drivers, the bcache nvm- > pages allocator can be treated as user of these two drivers. > > The nvm-pages allocator is a buddy-like allocator, which allocates size > in power-of-2 pages from the NVDIMM namespace. User space tool 'bcache' > has a new added '-M' option to format a NVDIMM namespace and register it > via sysfs interface as a bcache meta device. The nvm-pages kernel code > does a DAX mapping to map the whole namespace into system's memory > address range, and allocating the pages to requestion like typical buddy > allocator does. The major difference is nvm-pages allocator maintains > the pages allocated to each requester by a owner list which stored on > NVDIMM too. Owner list of different requester is tracked by a pre- > defined UUID, all the pages tracked in all owner lists are treated as > allocated busy pages and won't be initialized into buddy system after > the system reboot. > > I modify the bcache code to recognize the nvm meta device feature, > initialize journal on NVDIMM, and do journal I/Os on NVDIMM in the > following patches, > - bcache: add initial data structures for nvm pages > - bcache: use bucket index to set GC_MARK_METADATA for journal buckets > in bch_btree_gc_finish() > - bcache: add BCH_FEATURE_INCOMPAT_NVDIMM_META into incompat feature set > - bcache: initialize bcache journal for NVDIMM meta device > - bcache: support storing bcache journal into NVDIMM meta device > - bcache: read jset from NVDIMM pages for journal replay > - bcache: add sysfs interface register_nvdimm_meta to register NVDIMM > meta device > - bcache: use div_u64() in init_owner_info() > > The bcache journal code may request a block of power-of-2 size pages > from the nvm-pages allocator, normally it is a range of 256MB or 512MB > continuous pages range. During meta data journaling, the in-memory jsets > go into the calculated nvdimm pages location by kernel memcpy routine. > So the journaling I/Os won't go into block device (e.g. SSD) anymore, > the write and read for journal jsets happen on NVDIMM. > > The whole series is testing for a while and all addressed issues are > verified to be fixed. Now it is time to consider this series as an > initial code base of a commnity cooperation and have them in bcache > upstream for future development. > > Thanks in advance for taking this. Hi Jens, Could you please take a look on this? Thanks. Coly Li [snipped]