[merged mm-stable] mm-migrate-remove-pagehead-check-for-hugetlb-in-add_page_for_migration.patch removed from -mm tree

[merged mm-stable] mm-migrate-remove-pagehead-check-for-hugetlb-in-add_page_for_migration.patch removed from -mm tree

[Andrew Morton]

The quilt patch titled
     Subject: mm: migrate: remove PageHead() check for HugeTLB in add_page_for_migration()
has been removed from the -mm tree.  Its filename was
     mm-migrate-remove-pagehead-check-for-hugetlb-in-add_page_for_migration.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: Kefeng Wang <wangkefeng.wang@huawei.com>
Subject: mm: migrate: remove PageHead() check for HugeTLB in add_page_for_migration()
Date: Wed, 13 Sep 2023 17:51:30 +0800

There is some different between hugeTLB and THP behave when passed the
address of a tail page, for THP, it will migrate the entire THP page, but
for HugeTLB, it will return -EACCES, or -ENOENT before commit e66f17ff7177
("mm/hugetlb: take page table lock in follow_huge_pmd()"),

  -EACCES The page is mapped by multiple processes and can be moved
	  only if MPOL_MF_MOVE_ALL is specified.
  -ENOENT The page is not present.

But when check manual[1], both of the two errnos are not suitable, it is
better to keep the same behave between hugetlb and THP when passed the
address of a tail page, so let's just remove the PageHead() check for
HugeTLB.

[1] https://man7.org/linux/man-pages/man2/move_pages.2.html

Link: https://lkml.kernel.org/r/20230913095131.2426871-8-wangkefeng.wang@huawei.com
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Suggested-by: Mike Kravetz <mike.kravetz@oracle.com>
Acked-by: Zi Yan <ziy@nvidia.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/migrate.c |    6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

--- a/mm/migrate.c~mm-migrate-remove-pagehead-check-for-hugetlb-in-add_page_for_migration
+++ a/mm/migrate.c
@@ -2096,10 +2096,8 @@ static int add_page_for_migration(struct
 		goto out_putfolio;
 
 	if (folio_test_hugetlb(folio)) {
-		if (PageHead(page)) {
-			isolated = isolate_hugetlb(folio, pagelist);
-			err = isolated ? 1 : -EBUSY;
-		}
+		isolated = isolate_hugetlb(folio, pagelist);
+		err = isolated ? 1 : -EBUSY;
 	} else {
 		isolated = folio_isolate_lru(folio);
 		if (!isolated) {
_

Patches currently in -mm which might be from wangkefeng.wang@huawei.com are

mm-memory-add-vm_normal_folio_pmd.patch
mm-huge_memory-use-a-folio-in-do_huge_pmd_numa_page.patch
mm-memory-use-a-folio-in-do_numa_page.patch
mm-memory-make-numa_migrate_prep-to-take-a-folio.patch
mm-mempolicy-make-mpol_misplaced-to-take-a-folio.patch
sched-numa-mm-make-numa-migrate-functions-to-take-a-folio.patch