On Thu, Apr 09, 2020 at 02:41:27PM +0200, Christoph Hellwig wrote: > On Wed, Apr 08, 2020 at 05:22:03PM -0700, Ira Weiny wrote: > > > You mean something like XFS_IDONTCACHE? > > > > > > i.e. the functionality already exists in XFS to selectively evict an > > > inode from cache when the last reference to it is dropped rather > > > than let it go to the LRUs and hang around in memory. > > > > > > That flag can be set when changing the on disk DAX flag, and we can > > > tweak how it works so new cache hits don't clear it (as happens > > > now). Hence the only thing that can prevent eviction are active > > > references. > > > > > > That means we'll still need to stop the application and drop_caches, > > > because we need to close all the files and purge the dentries that > > > hold references to the inode before it can be evicted. > > > > That sounds like a great idea... > > > > Jan? Christoph? > > Sounds ok. Note that we could also pretty trivially lift > XFS_IDONTCACHE to the VFS if we need to apply the same scheme to > ext4. Yes I have been slowing working on ext4 in the background. So lifting XXX_IDONTCACHE to VFS will be part of that series. Thanks, Ira
