Re: [PATCH] mm: add lazyfree folio to lru tail

[Yu Zhao]

On Thu, Aug 15, 2024 at 6:33 AM gaoxu <gaoxu2@xxxxxxxxx> 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.
>
> Signed-off-by: gao xu <gaoxu2@xxxxxxxxxxx>
> ---
>  mm/swap.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/mm/swap.c b/mm/swap.c
> index 67786cb77..ed49643ec 100644
> --- a/mm/swap.c
> +++ b/mm/swap.c
> @@ -635,7 +635,7 @@ static void lru_lazyfree_fn(struct lruvec *lruvec, struct folio *folio)

Please work against the latest mm-unstable.

>                  * 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,

Kalesh has been working on something similar for lru_deactivate(), and
he can help test and review this patch.