Re: NVFS XFS metadata (was: [PATCH] pmem: export the symbols __copy_user_flushcache and __copy_from_user_flushcache)

From: Matthew Wilcox
Date: Wed Sep 23 2020 - 11:04:46 EST

On Wed, Sep 23, 2020 at 09:11:43AM -0400, Mikulas Patocka wrote:
> I also don't know how to implement journling on persistent memory :) On
> EXT4 or XFS you can pin dirty buffers in memory until the journal is
> flushed. This is obviously impossible on persistent memory. So, I'm
> considering implementing only some lightweight journaling that will
> guarantee atomicity between just a few writes.

That's a bit disappointing considering people have been publishing
papers on how to do umpteen different variations on persistent memory
journalling for the last five years.

for example