Re: [RFC PATCH 1/4] mm/vmscan: refactor reclaim_pages with reclaim_or_migrate_folios

SeongJae Park
2024-01-16T20:32:14Z

On Mon, 15 Jan 2024 13:52:49 +0900 Honggyu Kim <honggyu.kim@sk.com> wrote:

> Since we will introduce reclaim_pages like functions such as
> demote_pages and promote_pages, the most of the code can be shared.
>
> This is a preparation patch that introduces reclaim_or_migrate_folios()
> to cover all the logics, but it provides a handler for the different
> actions.
>
> No functional changes applied.
>
> Signed-off-by: Honggyu Kim <honggyu.kim@sk.com>
> ---
> mm/vmscan.c | 18 ++++++++++++------
> 1 file changed, 12 insertions(+), 6 deletions(-)
>
> diff --git a/mm/vmscan.c b/mm/vmscan.c
> index bba207f41b14..7ca2396ccc3b 100644
> --- a/mm/vmscan.c
> +++ b/mm/vmscan.c
> @@ -2107,15 +2107,16 @@ static unsigned int reclaim_folio_list(struct list_head *folio_list,
> return nr_reclaimed;
> }
>
> -unsigned long reclaim_pages(struct list_head *folio_list)
> +static unsigned long reclaim_or_migrate_folios(struct list_head *folio_list,
> + unsigned int (*handler)(struct list_head *, struct pglist_data *))

I'm not very sure if extending this function for general migration is the right
approach, since we have dedicated functions for the migration.

I'd like to hear others' opinions.

> {
> int nid;
> - unsigned int nr_reclaimed = 0;
> + unsigned int nr_folios = 0;
> LIST_HEAD(node_folio_list);
> unsigned int noreclaim_flag;
>
> if (list_empty(folio_list))
> - return nr_reclaimed;
> + return nr_folios;
>
> noreclaim_flag = memalloc_noreclaim_save();
>
> @@ -2129,15 +2130,20 @@ unsigned long reclaim_pages(struct list_head *folio_list)
> continue;
> }
>
> - nr_reclaimed += reclaim_folio_list(&node_folio_list, NODE_DATA(nid));
> + nr_folios += handler(&node_folio_list, NODE_DATA(nid));
> nid = folio_nid(lru_to_folio(folio_list));
> } while (!list_empty(folio_list));
>
> - nr_reclaimed += reclaim_folio_list(&node_folio_list, NODE_DATA(nid));
> + nr_folios += handler(&node_folio_list, NODE_DATA(nid));
>
> memalloc_noreclaim_restore(noreclaim_flag);
>
> - return nr_reclaimed;
> + return nr_folios;
> +}
> +
> +unsigned long reclaim_pages(struct list_head *folio_list)
> +{
> + return reclaim_or_migrate_folios(folio_list, reclaim_folio_list);
> }
>
> static unsigned long shrink_list(enum lru_list lru, unsigned long nr_to_scan,
> --
> 2.34.1