mm: Add split_folio_to_list()

This is a convenience function; split_huge_page_to_list() can take
any page in a folio (and does so on purpose because that page will
be the one which keeps the refcount).  But it's convenient for the
callers to pass the folio instead of the first page in the folio.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>

diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h
index e4c18ba8d3bf4aa1c00992d3e68cb42fd35261f9..71c073d411ac5c1ff4d1766e7d0913739b57d487 100644 (file)
--- a/include/linux/huge_mm.h
+++ b/include/linux/huge_mm.h
@@ -483,6 +483,12 @@ static inline bool thp_migration_supported(void)
 }
 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
 
+static inline int split_folio_to_list(struct folio *folio,
+               struct list_head *list)
+{
+       return split_huge_page_to_list(&folio->page, list);
+}
+
 /**
  * thp_size - Size of a transparent huge page.
  * @page: Head page of a transparent huge page.

diff --git a/mm/vmscan.c b/mm/vmscan.c
index 815fe89d37f944855a67792a732144650713686b..94729d2d112539aefb70dc8f5129b9841db382e9 100644 (file)
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -1715,16 +1715,16 @@ retry:
                                         * tail pages can be freed without IO.
                                         */
                                        if (!compound_mapcount(page) &&
-                                           split_huge_page_to_list(page,
-                                                                   page_list))
+                                           split_folio_to_list(folio,
+                                                               page_list))
                                                goto activate_locked;
                                }
                                if (!add_to_swap(page)) {
                                        if (!PageTransHuge(page))
                                                goto activate_locked_split;
                                        /* Fallback to swap normal pages */
-                                       if (split_huge_page_to_list(page,
-                                                                   page_list))
+                                       if (split_folio_to_list(folio,
+                                                               page_list))
                                                goto activate_locked;
 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
                                        count_vm_event(THP_SWPOUT_FALLBACK);
@@ -1740,7 +1740,7 @@ retry:
                        }
                } else if (unlikely(PageTransHuge(page))) {
                        /* Split file THP */
-                       if (split_huge_page_to_list(page, page_list))
+                       if (split_folio_to_list(folio, page_list))
                                goto keep_locked;
                }