On Mon, Mar 25, 2019 at 07:56:33PM +0200, Amir Goldstein wrote: > Sure, let's give that a shot. But allow me to stay skeptical, because > I don't think there is a one-size-fits-all solution. > If application doesn't need >4K atomicity and xfs imposes file-wide > read locks, there is bound to exist a workload where ext4 can guaranty > lower latencies than xfs. > > Then again, if we fix rw_semaphore to do a good enough job for my > workload, I may not care about those worst case workloads... Downgrading these long standing guarantees is simply not an option. Not quite sure what the I/O pattern of your workload is, but if it is reads from other regions than you write to you should look into implementing range locks.