+ mm-fix-numa-stats-for-thp-migration.patch added to -mm tree

+ mm-fix-numa-stats-for-thp-migration.patch added to -mm tree

[akpm]

The patch titled
     Subject: mm: fix numa stats for thp migration
has been added to the -mm tree.  Its filename is
     mm-fix-numa-stats-for-thp-migration.patch

This patch should soon appear at
    https://ozlabs.org/~akpm/mmots/broken-out/mm-fix-numa-stats-for-thp-migration.patch
and later at
    https://ozlabs.org/~akpm/mmotm/broken-out/mm-fix-numa-stats-for-thp-migration.patch

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------------------------------------------------------
From: Shakeel Butt <shakeelb@google.com>
Subject: mm: fix numa stats for thp migration

Currently the kernel is not correctly updating the numa stats for
NR_FILE_PAGES and NR_SHMEM on THP migration.  Fix that.  For NR_FILE_DIRTY
and NR_ZONE_WRITE_PENDING, although at the moment there is no need to
handle THP migration as kernel still does not have write support for file
THP but to be more future proof, this patch adds the THP support for those
stats as well.

Link: https://lkml.kernel.org/r/20210108155813.2914586-2-shakeelb@google.com
Fixes: e71769ae52609 ("mm: enable thp migration for shmem thp")
Signed-off-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Yang Shi <shy828301@gmail.com>
Reviewed-by: Roman Gushchin <guro@fb.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/migrate.c |   23 ++++++++++++-----------
 1 file changed, 12 insertions(+), 11 deletions(-)

--- a/mm/migrate.c~mm-fix-numa-stats-for-thp-migration
+++ a/mm/migrate.c
@@ -402,6 +402,7 @@ int migrate_page_move_mapping(struct add
 	struct zone *oldzone, *newzone;
 	int dirty;
 	int expected_count = expected_page_refs(mapping, page) + extra_count;
+	int nr = thp_nr_pages(page);
 
 	if (!mapping) {
 		/* Anonymous page without mapping */
@@ -437,7 +438,7 @@ int migrate_page_move_mapping(struct add
 	 */
 	newpage->index = page->index;
 	newpage->mapping = page->mapping;
-	page_ref_add(newpage, thp_nr_pages(page)); /* add cache reference */
+	page_ref_add(newpage, nr); /* add cache reference */
 	if (PageSwapBacked(page)) {
 		__SetPageSwapBacked(newpage);
 		if (PageSwapCache(page)) {
@@ -459,7 +460,7 @@ int migrate_page_move_mapping(struct add
 	if (PageTransHuge(page)) {
 		int i;
 
-		for (i = 1; i < HPAGE_PMD_NR; i++) {
+		for (i = 1; i < nr; i++) {
 			xas_next(&xas);
 			xas_store(&xas, newpage);
 		}
@@ -470,7 +471,7 @@ int migrate_page_move_mapping(struct add
 	 * to one less reference.
 	 * We know this isn't the last reference.
 	 */
-	page_ref_unfreeze(page, expected_count - thp_nr_pages(page));
+	page_ref_unfreeze(page, expected_count - nr);
 
 	xas_unlock(&xas);
 	/* Leave irq disabled to prevent preemption while updating stats */
@@ -493,17 +494,17 @@ int migrate_page_move_mapping(struct add
 		old_lruvec = mem_cgroup_lruvec(memcg, oldzone->zone_pgdat);
 		new_lruvec = mem_cgroup_lruvec(memcg, newzone->zone_pgdat);
 
-		__dec_lruvec_state(old_lruvec, NR_FILE_PAGES);
-		__inc_lruvec_state(new_lruvec, NR_FILE_PAGES);
+		__mod_lruvec_state(old_lruvec, NR_FILE_PAGES, -nr);
+		__mod_lruvec_state(new_lruvec, NR_FILE_PAGES, nr);
 		if (PageSwapBacked(page) && !PageSwapCache(page)) {
-			__dec_lruvec_state(old_lruvec, NR_SHMEM);
-			__inc_lruvec_state(new_lruvec, NR_SHMEM);
+			__mod_lruvec_state(old_lruvec, NR_SHMEM, -nr);
+			__mod_lruvec_state(new_lruvec, NR_SHMEM, nr);
 		}
 		if (dirty && mapping_can_writeback(mapping)) {
-			__dec_lruvec_state(old_lruvec, NR_FILE_DIRTY);
-			__dec_zone_state(oldzone, NR_ZONE_WRITE_PENDING);
-			__inc_lruvec_state(new_lruvec, NR_FILE_DIRTY);
-			__inc_zone_state(newzone, NR_ZONE_WRITE_PENDING);
+			__mod_lruvec_state(old_lruvec, NR_FILE_DIRTY, -nr);
+			__mod_zone_page_state(oldzone, NR_ZONE_WRITE_PENDING, -nr);
+			__mod_lruvec_state(new_lruvec, NR_FILE_DIRTY, nr);
+			__mod_zone_page_state(newzone, NR_ZONE_WRITE_PENDING, nr);
 		}
 	}
 	local_irq_enable();
_

Patches currently in -mm which might be from shakeelb@google.com are

mm-memcg-fix-memcg-file_dirty-numa-stat.patch
mm-fix-numa-stats-for-thp-migration.patch
mm-memcg-add-swapcache-stat-for-memcg-v2.patch