On Wed, Oct 4, 2023 at 12:46 PM Johannes Weiner <hannes@xxxxxxxxxxx> wrote: > > On Wed, Oct 04, 2023 at 12:36:22PM -0700, Nhat Pham 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. > > > > 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/ > > > > This should be added as the second prep patch in the following series: > > https://lore.kernel.org/all/20231003001828.2554080-1-nphamcs@xxxxxxxxx/ > > (hugetlb memcg accounting) > > > > and should go right before the following patch: > > hugetlb: memcg: account hugetlb-backed memory in memory controller > > > > Reported-by: Mike Kravetz <mike.kravetz@xxxxxxxxxx> > > Closes: https://lore.kernel.org/lkml/20231003171329.GB314430@monkey/ > > These two tags shouldn't be here, but in the fixlet instead. This is > the dependency patch. Otherwise looks good to me: > > > Suggested-by: Johannes Weiner <hannes@xxxxxxxxxxx> > > Signed-off-by: Nhat Pham <nphamcs@xxxxxxxxx> > > Acked-by: Johannes Weiner <hannes@xxxxxxxxxxx> Thanks for the review, Johannes!
