On Tue, Oct 3, 2023 at 4:31 PM Nhat Pham <nphamcs@xxxxxxxxx> wrote: > > On Tue, Oct 3, 2023 at 4:22 PM Yosry Ahmed <yosryahmed@xxxxxxxxxx> wrote: > > > > On Tue, Oct 3, 2023 at 4:14 PM Nhat Pham <nphamcs@xxxxxxxxx> wrote: > > > > > > For most migration use cases, only transfer the memcg data from the old > > > folio to the new folio, and clear the old folio's memcg data. No > > > charging and uncharging will be done. These use cases include the new > > > hugetlb memcg accounting behavior (which was not previously handled). > > > > > > This shaves off some work on the migration path, and avoids the > > > temporary double charging of a folio during its migration. > > > > > > The only exception is replace_page_cache_folio(), which will use the old > > > mem_cgroup_migrate() (now renamed to mem_cgroup_replace_folio). In that > > > context, the isolation of the old page isn't quite as thorough as with > > > migration, so we cannot use our new implementation directly. > > > > > > This patch is the result of the following discussion on the new hugetlb > > > memcg accounting behavior: > > > > > > https://lore.kernel.org/lkml/20231003171329.GB314430@monkey/ > > > > > > Reported-by: Mike Kravetz <mike.kravetz@xxxxxxxxxx> > > > Closes: https://lore.kernel.org/lkml/20231003171329.GB314430@monkey/ > > > Suggested-by: Johannes Weiner <hannes@xxxxxxxxxxx> > > > Signed-off-by: Nhat Pham <nphamcs@xxxxxxxxx> > > > > Does this patch fit before or after your series? In both cases I think > > there might be a problem for bisectability. > > Hmm my intention for this patch is as a fixlet. > (i.e it should be eventually squashed to the second patch of that series). > I just include the extra context on the fixlet for review purposes. > > My apologies - should have been much clearer. > (Perhaps I should just send out v4 at this point?) > It's really up to Andrew, just make it clear what the intention is. Thanks!
