"Pankaj Raghav (Samsung)" <kernel@xxxxxxxxxxxxxxxx> writes: >> > > > Add a config option PERSISTENT_HUGE_ZERO_FOLIO that will always allocate >> > > > the huge_zero_folio, and disable the shrinker so that huge_zero_folio is >> > > > never freed. >> > > > This makes using the huge_zero_folio without having to pass any mm struct and does >> > > > not tie the lifetime of the zero folio to anything, making it a drop-in >> > > > replacement for ZERO_PAGE. >> > > > >> > > > I have converted blkdev_issue_zero_pages() as an example as a part of >> > > > this series. I also noticed close to 4% performance improvement just by >> > > > replacing ZERO_PAGE with persistent huge_zero_folio. >> > > > >> > > > I will send patches to individual subsystems using the huge_zero_folio >> > > > once this gets upstreamed. >> > > > >> > > > Looking forward to some feedback. >> > > >> > > Why does it need to be compile-time? Maybe whoever needs huge zero page >> > > would just call get_huge_zero_page()/folio() on initialization to get it >> > > pinned? >> > >> > That's what v2 did, and this way here is cleaner. >> >> Sorry, RFC v2 I think. It got a bit confusing with series names/versions. >> > > Another reason we made it a compile time config is because not all > machines would want a PMD sized folio just for zeroing. For example, > Dave Hansen told in one of the early revisions that a small x86 VM would > not want this. > > So it is a default N, and it will be an opt-in. > I looked over the patches and I liked this design. This is much simpler and cleaner compared to the initial version. Thanks! -ritesh
