mm: fix numa stats for thp migration

mainline inclusion
from mainline-v5.11-rc5
commit 5c447d27
category: bugfix
bugzilla: 47675
CVE: NA

-------------------------------------------------

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: e71769ae ("mm: enable thp migration for shmem thp")
Signed-off-by: NShakeel Butt <shakeelb@google.com>
Acked-by: NYang Shi <shy828301@gmail.com>
Reviewed-by: NRoman 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: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: NLiu Shixin <liushixin2@huawei.com>
Reviewed-by: NKefeng Wang <wangkefeng.wang@huawei.com>
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>

mm/migrate.c

@@ -443,6 +443,7 @@ int migrate_page_move_mapping(struct address_space *mapping,
 	int dirty;
 	int expected_count = 1 + extra_count;
 	void **pslot;
+	int nr = hpage_nr_pages(page);
 
 	/*
 	 * Device public or private pages have an extra refcount as they are
@@ -506,7 +507,7 @@ int migrate_page_move_mapping(struct address_space *mapping,
 	 */
 	newpage->index = page->index;
 	newpage->mapping = page->mapping;
-	page_ref_add(newpage, hpage_nr_pages(page)); /* add cache reference */
+	page_ref_add(newpage, nr); /* add cache reference */
 	if (PageSwapBacked(page)) {
 		__SetPageSwapBacked(newpage);
 		if (PageSwapCache(page)) {
@@ -529,7 +530,7 @@ int migrate_page_move_mapping(struct address_space *mapping,
 		int i;
 		int index = page_index(page);
 
-		for (i = 1; i < HPAGE_PMD_NR; i++) {
+		for (i = 1; i < nr; i++) {
 			pslot = radix_tree_lookup_slot(&mapping->i_pages,
 						       index + i);
 			radix_tree_replace_slot(&mapping->i_pages, pslot,
@@ -542,7 +543,7 @@ int migrate_page_move_mapping(struct address_space *mapping,
 	 * to one less reference.
 	 * We know this isn't the last reference.
 	 */
-	page_ref_unfreeze(page, expected_count - hpage_nr_pages(page));
+	page_ref_unfreeze(page, expected_count - nr);
 
 	xa_unlock(&mapping->i_pages);
 	/* Leave irq disabled to prevent preemption while updating stats */
@@ -558,17 +559,17 @@ int migrate_page_move_mapping(struct address_space *mapping,
 	 * are mapped to swap space.
 	 */
 	if (newzone != oldzone) {
-		__dec_node_state(oldzone->zone_pgdat, NR_FILE_PAGES);
-		__inc_node_state(newzone->zone_pgdat, NR_FILE_PAGES);
+		__mod_node_page_state(oldzone->zone_pgdat, NR_FILE_PAGES, -nr);
+		__mod_node_page_state(newzone->zone_pgdat, NR_FILE_PAGES, nr);
 		if (PageSwapBacked(page) && !PageSwapCache(page)) {
-			__dec_node_state(oldzone->zone_pgdat, NR_SHMEM);
-			__inc_node_state(newzone->zone_pgdat, NR_SHMEM);
+			__mod_node_page_state(oldzone->zone_pgdat, NR_SHMEM, -nr);
+			__mod_node_page_state(newzone->zone_pgdat, NR_SHMEM, nr);
 		}
 		if (dirty && mapping_cap_account_dirty(mapping)) {
-			__dec_node_state(oldzone->zone_pgdat, NR_FILE_DIRTY);
-			__dec_zone_state(oldzone, NR_ZONE_WRITE_PENDING);
-			__inc_node_state(newzone->zone_pgdat, NR_FILE_DIRTY);
-			__inc_zone_state(newzone, NR_ZONE_WRITE_PENDING);
+			__mod_node_page_state(oldzone->zone_pgdat, NR_FILE_DIRTY, -nr);
+			__mod_zone_page_state(oldzone, NR_ZONE_WRITE_PENDING, -nr);
+			__mod_node_page_state(newzone->zone_pgdat, NR_FILE_DIRTY, nr);
+			__mod_zone_page_state(newzone, NR_ZONE_WRITE_PENDING, nr);
 		}
 	}
 	local_irq_enable();