On Sun, Oct 25, 2020 at 4:42 AM Chengguang Xu <cgxu519@xxxxxxxxxxxx> wrote: > > Current syncfs(2) syscall on overlayfs just calls sync_filesystem() > on upper_sb to synchronize whole dirty inodes in upper filesystem > regardless of the overlay ownership of the inode. In the use case of > container, when multiple containers using the same underlying upper > filesystem, it has some shortcomings as below. > > (1) Performance > Synchronization is probably heavy because it actually syncs unnecessary > inodes for target overlayfs. > > (2) Interference > Unplanned synchronization will probably impact IO performance of > unrelated container processes on the other overlayfs. > > This series try to implement containerized syncfs for overlayfs so that > only sync target dirty upper inodes which are belong to specific overlayfs > instance. By doing this, it is able to reduce cost of synchronization and > will not seriously impact IO performance of unrelated processes. Series looks good at first glance. Still need to do an in-depth review. In the meantime can you post some numbers showing the performance improvements? Thanks, Miklos
