From fbed53b47770b978be290cec0f4f22577766c12d Mon Sep 17 00:00:00 2001 From: Huang Ying Date: Wed, 17 Aug 2022 16:14:03 +0800 Subject: [PATCH] migrate_pages(): fix THP failure counting for -ENOMEM In unmap_and_move(), if the new THP cannot be allocated, -ENOMEM will be returned, and migrate_pages() will try to split the THP unless "reason" is MR_NUMA_MISPLACED (that is, nosplit == true). But when nosplit == true, the THP migration failure will not be counted. This is incorrect, so in this patch, the THP migration failure will be counted for -ENOMEM regardless of nosplit is true or false. The nr_failed counting isn't fixed because it's not used. Added some comments for it per Baolin's suggestion. Link: https://lkml.kernel.org/r/20220817081408.513338-4-ying.huang@intel.com Fixes: 5984fabb6e82 ("mm: move_pages: report the number of non-attempted pages") Signed-off-by: "Huang, Ying" Reviewed-by: Baolin Wang Reviewed-by: Oscar Salvador Cc: Zi Yan Cc: Yang Shi Signed-off-by: Andrew Morton --- mm/migrate.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/mm/migrate.c b/mm/migrate.c index 19a9b26af7e2..ae55f08e72ce 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -1494,11 +1494,11 @@ retry: /* * 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 && !nosplit) { + if (is_thp) { nr_thp_failed++; - if (!try_split_thp(page, &thp_split_pages)) { + /* THP NUMA faulting doesn't split THP to retry. */ + if (!nosplit && !try_split_thp(page, &thp_split_pages)) { nr_thp_split++; goto retry; } @@ -1514,6 +1514,7 @@ retry: * the caller otherwise the page refcnt will be leaked. */ list_splice_init(&thp_split_pages, from); + /* nr_failed isn't updated for not used */ nr_thp_failed += thp_retry; goto out; case -EAGAIN: