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 <dan.j.williams@xxxxxxxxx> wrote: > > On Wed, Jan 31, 2018 at 4:45 PM, Andiry Xu <andiry@xxxxxxxxx> 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 EXT4…) > >> 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 “clean slate” 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 what’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 <jack@xxxxxxxx> SUSE Labs, CR -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>
