On Wed, Mar 30, 2022 at 11:45:56AM -0400, Johannes Weiner wrote: > > FYI, I started redoing that version and I think with all the cleanups > > to filemap.c and the readahead code this can be done fairly nicely now: > > > > http://git.infradead.org/users/hch/block.git/commitdiff/666abb29c6db870d3941acc5ac19e83fbc72cfd4 > > Yes, it's definitely much nicer now with the MM instantiating the > pages for ->readpage(s). > > But AFAICS this breaks compressed btrfs (and erofs?) because those > still do additional add_to_page_cache_lru() and bio submissions. In btrfs, add_ra_bio_pages only passed freshly allocated pages to add_to_page_cache_lru. These can't really have PageWorkingSet set, can they? In erofs they can also come from a local page pool, but I think otherwise the same applies.
