回复: [PATCH v2] mm: add lazyfree folio to lru tail

[gaoxu <gaoxu2@honor.com>]

> 
> On Fri, Aug 16, 2024 at 7:48 PM gaoxu <gaoxu2@honor.com> wrote:
> >
> > Replace lruvec_add_folio with lruvec_add_folio_tail in the lru_lazyfree_fn:
> > 1. The lazy-free folio is added to the LRU_INACTIVE_FILE list. If it's
> >    moved to the LRU tail, it allows for faster release lazy-free folio and
> >    reduces the impact on file refault.
> > 2. When mglru is enabled, the lazy-free folio is reclaimabled and should be
> >    added using lru_gen_add_folio(lruvec, folio, true) instead of
> >    lru_gen_add_folio(lruvec, folio, false) for adding to gen.
> >
> > With the change in place, workingset_refault_file is reduced by 33% in
> > the continuous startup testing of the applications in the Android system.
> >
> 
> Hi Gao,
> 
> Just curious, in which scenario are we frequently calling MADV_FREE but not
> MADV_DONTNEED?
Hi Song,
 Android ART use MADV_FREE, please refer to the following link.
 https://android-review.googlesource.com/c/platform/art/+/2633132
> 
> > Signed-off-by: gao xu <gaoxu2@hihonor.com>
> > ---
> > V1 -> V2: Based on the latest mm-unstable, recreate the patch.
> >
> >  mm/swap.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/mm/swap.c b/mm/swap.c
> > index 6b838986d..e0dbfc983 100644
> > --- a/mm/swap.c
> > +++ b/mm/swap.c
> > @@ -641,7 +641,7 @@ static void lru_lazyfree(struct lruvec *lruvec, struct
> folio *folio)
> >          * anonymous folios
> >          */
> >         folio_clear_swapbacked(folio);
> > -       lruvec_add_folio(lruvec, folio);
> > +       lruvec_add_folio_tail(lruvec, folio);
> >
> >         __count_vm_events(PGLAZYFREE, nr_pages);
> >         __count_memcg_events(lruvec_memcg(lruvec), PGLAZYFREE,
> > nr_pages);
> > --
> > 2.17.1