On Thu, Jul 04, 2019 at 09:34:13PM +0800, Gao Xiang wrote: > EROFS file system has been in Linux-staging for about a year. > It has been proved to be stable enough to move out of staging > by 10+ millions of HUAWEI Android mobile phones on the market > from EMUI 9.0.1, and it was promoted as one of the key features > of EMUI 9.1 [1], including P30(pro). > > EROFS is a read-only file system designed to save extra storage > space with guaranteed end-to-end performance by applying > fixed-size output compression, inplace I/O and decompression > inplace technologies [2] to Linux filesystem. > > In our observation, EROFS is one of the fastest Linux compression > filesystem using buffered I/O in the world. It will support > direct I/O in the future if needed. EROFS even has better read > performance in a large CR range compared with generic uncompressed > file systems with proper CPU-storage combination, which is > a reason why erofs can be landed to speed up mobile phone > performance, and which can be probably used for other use cases > such as LiveCD and Docker image as well. > > Currently erofs supports 4k LZ4 fixed-size output compression > since LZ4 is the fastest widely-used decompression solution in > the world and 4k leads to unnoticable read amplification for > the worst case. More compression algorithms and cluster sizes > could be added later, which depends on the real requirement. > > More informations about erofs itself are available at: > Documentation/filesystems/erofs.txt > https://kccncosschn19eng.sched.com/event/Nru2/erofs-an-introduction-and-our-smartphone-practice-xiang-gao-huawei > > erofs-utils (mainly mkfs.erofs now) is available at > git://git.kernel.org/pub/scm/linux/kernel/git/xiang/erofs-utils.git > > Preliminary iomap support has been pending in erofs mailing > list by Chao Yu. The key issue is that current iomap doesn't > support tail-end packing inline data yet, it should be > resolved later. > > Thanks to many contributors in the last year, the code is more > clean and improved. We hope erofs can be used in wider use cases > so let's promote erofs out of staging and enhance it more actively. > > Share comments about erofs! We think erofs is useful to > community as a part of Linux upstream :) I don't know if this format is easy for the linux-fsdevel people to review, it forces them to look at the in-kernel code, which makes it hard to quote. Perhaps just make a patch that adds the filesystem to the tree and after it makes it through review, I can delete the staging version? We've been doing that for wifi drivers that move out of staging as it seems to be a bit easier. thanks, greg k-h
