diff mbox series

[v3,5/7] mm: migrate: don't split THP for misplaced NUMA page

Message ID 20210518200801.7413-6-shy828301@gmail.com (mailing list archive)
State New, archived
Headers show
Series mm: thp: use generic THP migration for NUMA hinting fault | expand

Commit Message

Yang Shi May 18, 2021, 8:07 p.m. UTC 
The old behavior didn't split THP if migration is failed due to lack of
memory on the target node.  But the THP migration does split THP, so keep
the old behavior for misplaced NUMA page migration.

Acked-by: Mel Gorman <mgorman@suse.de>
Signed-off-by: Yang Shi <shy828301@gmail.com>
---
 mm/migrate.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)
diff mbox series

Patch

diff --git a/mm/migrate.c b/mm/migrate.c
index 26f79f516100..035daaec1ca0 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -1420,6 +1420,7 @@  int migrate_pages(struct list_head *from, new_page_t get_new_page,
 	int swapwrite = current->flags & PF_SWAPWRITE;
 	int rc, nr_subpages;
 	LIST_HEAD(ret_pages);
+	bool nosplit = (reason == MR_NUMA_MISPLACED);
 
 	trace_mm_migrate_pages_start(mode, reason);
 
@@ -1491,8 +1492,9 @@  int migrate_pages(struct list_head *from, new_page_t get_new_page,
 				/*
 				 * When memory is low, don't bother to try to migrate
 				 * other pages, just exit.
+				 * THP NUMA faulting doesn't split THP to retry.
 				 */
-				if (is_thp) {
+				if (is_thp && !nosplit) {
 					if (!try_split_thp(page, &page2, from)) {
 						nr_thp_split++;
 						goto retry;