On Wed, Mar 30, 2022 at 12:17:09PM -0400, Johannes Weiner wrote: > It's add_to_page_cache_lru() that sets the flag. > > Basically, when a PageWorkingset (hot) page gets reclaimed, the bit is > stored in the vacated tree slot. When the entry is brought back in, > add_to_page_cache_lru() transfers it to the newly allocated page. Ok. In this case my patch didn't quite do the right thing for readahead either. But that does leave a question for the btrfs compressed case, which only adds extra pages to a read to readahad a bigger cluster size - that is these pages are not read at the request of the VM. Does it really make sense to do PSI accounting for them in that case?
