The patch titled
Subject: mm: migrate: remove PageHead() check for HugeTLB in add_page_for_migration()
has been added to the -mm mm-unstable branch. Its filename is
mm-migrate-remove-pagehead-check-for-hugetlb-in-add_page_for_migration.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-migrate-remove-pagehead-check-for-hugetlb-in-add_page_for_migration.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Before you just go and hit "reply", please:
a) Consider who else should be cc'ed
b) Prefer to cc a suitable mailing list as well
c) Ideally: find the original patch on the mailing list and do a
reply-to-all to that, adding suitable additional cc's
*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next via the mm-everything
branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
and is updated there every 2-3 working days
------------------------------------------------------
From: Kefeng Wang <wangkefeng.wang@xxxxxxxxxx>
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@xxxxxxxxxx
Signed-off-by: Kefeng Wang <wangkefeng.wang@xxxxxxxxxx>
Suggested-by: Mike Kravetz <mike.kravetz@xxxxxxxxxx>
Acked-by: Zi Yan <ziy@xxxxxxxxxx>
Cc: David Hildenbrand <david@xxxxxxxxxx>
Cc: "Huang, Ying" <ying.huang@xxxxxxxxx>
Cc: Hugh Dickins <hughd@xxxxxxxxxx>
Cc: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
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
@@ -2093,10 +2093,8 @@ 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@xxxxxxxxxx are
mm-migrate-remove-pagetranshuge-check-in-numamigrate_isolate_page.patch
mm-migrate-remove-thp-mapcount-check-in-numamigrate_isolate_page.patch
mm-migrate-convert-numamigrate_isolate_page-to-numamigrate_isolate_folio.patch
mm-migrate-convert-migrate_misplaced_page-to-migrate_misplaced_folio.patch
mm-migrate-use-__folio_test_movable.patch
mm-migrate-use-a-folio-in-add_page_for_migration.patch
mm-migrate-remove-pagehead-check-for-hugetlb-in-add_page_for_migration.patch
mm-migrate-remove-isolated-variable-in-add_page_for_migration.patch
