mm: migrate: convert migrate_misplaced_page() to migrate_misplaced_folio()

At present, numa balance only support base page and PMD-mapped THP, but we
will expand to support to migrate large folio/pte-mapped THP in the
future, it is better to make migrate_misplaced_page() to take a folio
instead of a page, and rename it to migrate_misplaced_folio(), it is a
preparation, also this remove several compound_head() calls.

Link: https://lkml.kernel.org/r/20230913095131.2426871-5-wangkefeng.wang@huawei.com
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/include/linux/migrate.h b/include/linux/migrate.h
index 711dd9412561f6291f73e35b6a8f0c75fa7f1b0b..2ce13e8a309bdcc6b9a05448471e62cdf62aae88 100644 (file)
--- a/include/linux/migrate.h
+++ b/include/linux/migrate.h
@@ -142,10 +142,10 @@ const struct movable_operations *page_movable_ops(struct page *page)
 }
 
 #ifdef CONFIG_NUMA_BALANCING
-int migrate_misplaced_page(struct page *page, struct vm_area_struct *vma,
+int migrate_misplaced_folio(struct folio *folio, struct vm_area_struct *vma,
                           int node);
 #else
-static inline int migrate_misplaced_page(struct page *page,
+static inline int migrate_misplaced_folio(struct folio *folio,
                                         struct vm_area_struct *vma, int node)
 {
        return -EAGAIN; /* can't migrate now */

diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 1cfd83e917484770c54feb110b254910de2151bf..5c20e43782e40e11a08f50f14699813bb06958cc 100644 (file)
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -1567,7 +1567,7 @@ vm_fault_t do_huge_pmd_numa_page(struct vm_fault *vmf)
        spin_unlock(vmf->ptl);
        writable = false;
 
-       migrated = migrate_misplaced_page(page, vma, target_nid);
+       migrated = migrate_misplaced_folio(page_folio(page), vma, target_nid);
        if (migrated) {
                flags |= TNF_MIGRATED;
                page_nid = target_nid;

diff --git a/mm/memory.c b/mm/memory.c
index 0739ccb00e6120b7ccd9aa2948ea68743a639781..d956b231e835abe26f1c92fc301ca99aeb094d79 100644 (file)
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -4812,7 +4812,7 @@ static vm_fault_t do_numa_page(struct vm_fault *vmf)
        writable = false;
 
        /* Migrate to the requested node */
-       if (migrate_misplaced_page(page, vma, target_nid)) {
+       if (migrate_misplaced_folio(page_folio(page), vma, target_nid)) {
                page_nid = target_nid;
                flags |= TNF_MIGRATED;
        } else {

diff --git a/mm/migrate.c b/mm/migrate.c
index 1f1aebe8da18fb35a0662feaf457a013bf84e307..1b848f6b5fbc6c96e9ac3b7da6d4ca95f564e252 100644 (file)
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -2516,55 +2516,58 @@ static int numamigrate_isolate_folio(pg_data_t *pgdat, struct folio *folio)
 }
 
 /*
- * Attempt to migrate a misplaced page to the specified destination
+ * Attempt to migrate a misplaced folio to the specified destination
  * node. Caller is expected to have an elevated reference count on
- * the page that will be dropped by this function before returning.
+ * the folio that will be dropped by this function before returning.
  */
-int migrate_misplaced_page(struct page *page, struct vm_area_struct *vma,
-                          int node)
+int migrate_misplaced_folio(struct folio *folio, struct vm_area_struct *vma,
+                           int node)
 {
        pg_data_t *pgdat = NODE_DATA(node);
        int isolated;
        int nr_remaining;
        unsigned int nr_succeeded;
        LIST_HEAD(migratepages);
-       int nr_pages = thp_nr_pages(page);
+       int nr_pages = folio_nr_pages(folio);
 
        /*
-        * Don't migrate file pages that are mapped in multiple processes
+        * Don't migrate file folios that are mapped in multiple processes
         * with execute permissions as they are probably shared libraries.
+        * To check if the folio is shared, ideally we want to make sure
+        * every page is mapped to the same process. Doing that is very
+        * expensive, so check the estimated mapcount of the folio instead.
         */
-       if (page_mapcount(page) != 1 && page_is_file_lru(page) &&
+       if (folio_estimated_sharers(folio) != 1 && folio_is_file_lru(folio) &&
            (vma->vm_flags & VM_EXEC))
                goto out;
 
        /*
-        * Also do not migrate dirty pages as not all filesystems can move
-        * dirty pages in MIGRATE_ASYNC mode which is a waste of cycles.
+        * Also do not migrate dirty folios as not all filesystems can move
+        * dirty folios in MIGRATE_ASYNC mode which is a waste of cycles.
         */
-       if (page_is_file_lru(page) && PageDirty(page))
+       if (folio_is_file_lru(folio) && folio_test_dirty(folio))
                goto out;
 
-       isolated = numamigrate_isolate_folio(pgdat, page_folio(page));
+       isolated = numamigrate_isolate_folio(pgdat, folio);
        if (!isolated)
                goto out;
 
-       list_add(&page->lru, &migratepages);
+       list_add(&folio->lru, &migratepages);
        nr_remaining = migrate_pages(&migratepages, alloc_misplaced_dst_folio,
                                     NULL, node, MIGRATE_ASYNC,
                                     MR_NUMA_MISPLACED, &nr_succeeded);
        if (nr_remaining) {
                if (!list_empty(&migratepages)) {
-                       list_del(&page->lru);
-                       mod_node_page_state(page_pgdat(page), NR_ISOLATED_ANON +
-                                       page_is_file_lru(page), -nr_pages);
-                       putback_lru_page(page);
+                       list_del(&folio->lru);
+                       node_stat_mod_folio(folio, NR_ISOLATED_ANON +
+                                       folio_is_file_lru(folio), -nr_pages);
+                       folio_putback_lru(folio);
                }
                isolated = 0;
        }
        if (nr_succeeded) {
                count_vm_numa_events(NUMA_PAGE_MIGRATE, nr_succeeded);
-               if (!node_is_toptier(page_to_nid(page)) && node_is_toptier(node))
+               if (!node_is_toptier(folio_nid(folio)) && node_is_toptier(node))
                        mod_node_page_state(pgdat, PGPROMOTE_SUCCESS,
                                            nr_succeeded);
        }
@@ -2572,7 +2575,7 @@ int migrate_misplaced_page(struct page *page, struct vm_area_struct *vma,
        return isolated;
 
 out:
-       put_page(page);
+       folio_put(folio);
        return 0;
 }
 #endif /* CONFIG_NUMA_BALANCING */