From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pl0-f70.google.com (mail-pl0-f70.google.com [209.85.160.70]) by kanga.kvack.org (Postfix) with ESMTP id E8C306B02FC for ; Wed, 7 Feb 2018 05:41:29 -0500 (EST) Received: by mail-pl0-f70.google.com with SMTP id f1so199591plb.7 for ; Wed, 07 Feb 2018 02:41:29 -0800 (PST) Received: from mx2.suse.de (mx2.suse.de. [195.135.220.15]) by mx.google.com with ESMTPS id a91-v6si908853pld.125.2018.02.07.02.41.28 for (version=TLS1 cipher=AES128-SHA bits=128/128); Wed, 07 Feb 2018 02:41:28 -0800 (PST) Date: Wed, 7 Feb 2018 11:41:23 +0100 From: Jan Kara Subject: Re: [LSF/MM TOPIC] Native NVMM file systems Message-ID: <20180207104123.64bjccnfzvnqqor6@quack2.suse.cz> References: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: Sender: owner-linux-mm@kvack.org List-ID: To: Dan Williams Cc: Andiry Xu , lsf-pc@lists.linux-foundation.org, Linux FS Devel , Linux MM , "linux-nvdimm@lists.01.org" , david , Matthew Wilcox , swanson@cs.ucsd.edu, jix024@cs.ucsd.edu, Jan Kara , Ross Zwisler On Wed 31-01-18 17:13:37, Dan Williams wrote: > [ adding Jan and Ross ] > > On Wed, Jan 31, 2018 at 5:03 PM, Dan Williams wrote: > > On Wed, Jan 31, 2018 at 4:45 PM, Andiry Xu wrote: > >> PMEM/DAX should allow for significant improvements in file system > >> performance and enable new programming models that allow direct, > >> efficient access to PMEM from userspace. Achieving these gains in > >> existing file systems built for block devices (e.g., XFS and EXT4a?|) > >> presents a range of challenges (e.g., > >> https://lkml.org/lkml/2016/9/11/159) and has been the subject of a lot > >> of recent work on ext4 and xfs. > >> > >> An alternative is to build a NVMM-aware file system from scratch that > >> takes full advantage of the performance that PMEM offers and avoids > >> the complexity that block-based file systems include to maximize > >> performance on slow storage (e.g., relaxing atomicity constraints on > >> many operations). Of course, it also brings with it the complexity of > >> another file system. > >> > >> We recently sent out a patch set for one-such a??clean slatea?? NVMM-aware > >> file system called NOVA. NOVA is log-structured DAX file system with > >> several nice features: > >> > >> * High performance, especially in metadata operations due to efficient > >> fine-grained logging > >> * High scalability with per-CPU memory pool and per-inode logging > >> * Strong metadata and data atomicity guarantees for all operations > >> * Full filesystem snapshot support with DAX-mmap > >> * Metadata replication/checksums and RAID-4 style data protection > >> > >> At the summit, we would like to discuss the trade-offs between > >> adapting NVMM features to existing file systems vs. creating/adopting > >> a purpose-built file system for NVMM. NOVA serves as useful starting > >> point for that discussion by demonstrating whata??s possible. It may > >> also suggest some features that could be adapted to other file systems > >> to improve NVMM performance. > >> > >> We welcome people that are interested in file systems and NVM/DAX. > >> Particular people that would be useful to have in attendance are Dan > >> Williams, Dave Chinner, and Matthew Wilcox. > > > > The rest of the fs-dax crew would also be useful to have: > > > > Jan Kara > > Ross Zwisler Thanks Dan. Yes, I'd be interested in discussions about NOVA. In fact I guess the biggest obstacle is currently the review bandwidth. New filesystem is a substantial chunk of code and although it does not have to be perfect to include it in the kernel it still needs at least some basic review... Honza -- Jan Kara SUSE Labs, CR -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org