[v3 PATCH 5/7] mm: migrate: don't split THP for misplaced NUMA page
From: Yang Shi <hidden>
Date: 2021-05-18 20:08:50
Also in:
linux-s390, lkml
Subsystem:
memory management, memory management - memory policy and migration, the rest · Maintainers:
Andrew Morton, David Hildenbrand, Linus Torvalds
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 <redacted> --- mm/migrate.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
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;
--
2.26.2