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

[Honggyu Kim]

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....@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 
*))
 {
        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