Messages in this thread | | | Date | Fri, 15 Mar 2024 11:43:19 +0100 | Subject | Re: [PATCH v4 5/6] mm: vmscan: Avoid split during shrink_folio_list() | From | David Hildenbrand <> |
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On 11.03.24 16:00, Ryan Roberts wrote: > Now that swap supports storing all mTHP sizes, avoid splitting large > folios before swap-out. This benefits performance of the swap-out path > by eliding split_folio_to_list(), which is expensive, and also sets us > up for swapping in large folios in a future series. > > If the folio is partially mapped, we continue to split it since we want > to avoid the extra IO overhead and storage of writing out pages > uneccessarily. > > Signed-off-by: Ryan Roberts <ryan.roberts@arm.com> > --- > mm/vmscan.c | 9 +++++---- > 1 file changed, 5 insertions(+), 4 deletions(-) > > diff --git a/mm/vmscan.c b/mm/vmscan.c > index cf7d4cf47f1a..0ebec99e04c6 100644 > --- a/mm/vmscan.c > +++ b/mm/vmscan.c > @@ -1222,11 +1222,12 @@ static unsigned int shrink_folio_list(struct list_head *folio_list, > if (!can_split_folio(folio, NULL)) > goto activate_locked; > /* > - * Split folios without a PMD map right > - * away. Chances are some or all of the > - * tail pages can be freed without IO. > + * Split partially mapped folios map > + * right away. Chances are some or all > + * of the tail pages can be freed > + * without IO. > */ > - if (!folio_entire_mapcount(folio) && > + if (!list_empty(&folio->_deferred_list) && > split_folio_to_list(folio, > folio_list)) > goto activate_locked;
Not sure if we might have to annotate that with data_race().
Reviewed-by: David Hildenbrand <david@redhat.com>
-- Cheers,
David / dhildenb
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