On 10/30/24 22:56, Shakeel Butt wrote: > On Wed, Oct 30, 2024 at 10:35:47AM GMT, Joanne Koong wrote: >> On Wed, Oct 30, 2024 at 10:27 AM Bernd Schubert >> <bernd.schubert@xxxxxxxxxxx> wrote: >>> >>> >>> Hmm, if tmp pages can be compacted, isn't that a problem for splice? >>> I.e. I don't understand what the difference between tmp page and >>> write-back page for migration. >>> >> >> That's a great question! I have no idea how compaction works for pages >> being used in splice. Shakeel, do you know the answer to this? >> > > Sorry for the late response. I still have to go through other unanswered > questions but let me answer this one quickly. From the way the tmp pages > are allocated, it does not seem like they are movable and thus are not > target for migration/compaction. > > The page with the writeback bit set is actually just a user memory page > cache which is moveable but due to, at the moment, under writeback it > temporarily becomes unmovable to not cause corruption. Thanks a lot for your quick reply Shakeel! (Actually very fast!). With that, it confirms what I wrote earlier - removing tmp and ignoring fuse writeback pages in migration should not make any difference regarding overall system performance. Unless I miss something, more on the contrary as additional memory pressure expensive page copying is being removed. Thanks, Bernd
