On Fri, Feb 22, 2019 at 10:20:08AM -0800, Darrick J. Wong wrote: > Hi all! > > Uh, we have an internal customer <cough> who's been trying out MAP_SYNC > on pmem, and they've observed that one has to do a fair amount of > legwork (in the form of mkfs.xfs parameters) to get the kernel to set up > 2M PMD mappings. They (of course) want to mmap hundreds of GB of pmem, > so the PMD mappings are much more efficient. > > I started poking around w.r.t. what mkfs.xfs was doing and realized that > if the fsdax pmem device advertised iomin/ioopt of 2MB, then mkfs will > set up all the parameters automatically. Below is my ham-handed attempt > to teach the kernel to do this. What's the before and after mkfs output? (need to see the context that this "fixes" before I comment) Cheers, Dave. -- Dave Chinner david@xxxxxxxxxxxxx
