[merged mm-stable] migrate_pages-fix-thp-failure-counting-for-enomem.patch removed from -mm tree

[merged mm-stable] migrate_pages-fix-thp-failure-counting-for-enomem.patch removed from -mm tree

[Andrew Morton]

The quilt patch titled
     Subject: migrate_pages(): fix THP failure counting for -ENOMEM
has been removed from the -mm tree.  Its filename was
     migrate_pages-fix-thp-failure-counting-for-enomem.patch

This patch was dropped because it was merged into the mm-stable branch
of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

------------------------------------------------------
From: Huang Ying <ying.huang@intel.com>
Subject: migrate_pages(): fix THP failure counting for -ENOMEM
Date: Wed, 17 Aug 2022 16:14:03 +0800

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" <ying.huang@intel.com>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Cc: Zi Yan <ziy@nvidia.com>
Cc: Yang Shi <shy828301@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/migrate.c |    7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

--- a/mm/migrate.c~migrate_pages-fix-thp-failure-counting-for-enomem
+++ a/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:
_

Patches currently in -mm which might be from ying.huang@intel.com are