The patch titled
Subject: mm/migration: return errno when isolate_huge_page failed
has been added to the -mm mm-unstable branch. Its filename is
mm-migration-return-errno-when-isolate_huge_page-failed.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-migration-return-errno-when-isolate_huge_page-failed.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Miaohe Lin <linmiaohe@xxxxxxxxxx>
Subject: mm/migration: return errno when isolate_huge_page failed
Date: Mon, 30 May 2022 19:30:15 +0800
We might fail to isolate huge page due to e.g. the page is under
migration which cleared HPageMigratable. We should return errno in this
case rather than always return 1 which could confuse the user, i.e. the
caller might think all of the memory is migrated while the hugetlb page is
left behind. We make the prototype of isolate_huge_page consistent with
isolate_lru_page as suggested by Huang Ying and rename isolate_huge_page
to isolate_hugetlb as suggested by Muchun to improve the readability.
Link: https://lkml.kernel.org/r/20220530113016.16663-4-linmiaohe@xxxxxxxxxx
Fixes: e8db67eb0ded ("mm: migrate: move_pages() supports thp migration")
Signed-off-by: Miaohe Lin <linmiaohe@xxxxxxxxxx>
Suggested-by: Huang Ying <ying.huang@xxxxxxxxx>
Reported-by: kernel test robot <lkp@xxxxxxxxx> (build error)
Cc: Alistair Popple <apopple@xxxxxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxx>
Cc: Christoph Lameter <cl@xxxxxxxxx>
Cc: David Hildenbrand <david@xxxxxxxxxx>
Cc: David Howells <dhowells@xxxxxxxxxx>
Cc: Mike Kravetz <mike.kravetz@xxxxxxxxxx>
Cc: Muchun Song <songmuchun@xxxxxxxxxxxxx>
Cc: Oscar Salvador <osalvador@xxxxxxx>
Cc: Peter Xu <peterx@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/hugetlb.h | 6 +++---
mm/gup.c | 2 +-
mm/hugetlb.c | 11 +++++------
mm/memory-failure.c | 2 +-
mm/memory_hotplug.c | 2 +-
mm/mempolicy.c | 2 +-
mm/migrate.c | 7 ++++---
7 files changed, 16 insertions(+), 16 deletions(-)
--- a/include/linux/hugetlb.h~mm-migration-return-errno-when-isolate_huge_page-failed
+++ a/include/linux/hugetlb.h
@@ -170,7 +170,7 @@ bool hugetlb_reserve_pages(struct inode
vm_flags_t vm_flags);
long hugetlb_unreserve_pages(struct inode *inode, long start, long end,
long freed);
-bool isolate_huge_page(struct page *page, struct list_head *list);
+int isolate_hugetlb(struct page *page, struct list_head *list);
int get_hwpoison_huge_page(struct page *page, bool *hugetlb);
int get_huge_page_for_hwpoison(unsigned long pfn, int flags);
void putback_active_hugepage(struct page *page);
@@ -376,9 +376,9 @@ static inline pte_t *huge_pte_offset(str
return NULL;
}
-static inline bool isolate_huge_page(struct page *page, struct list_head *list)
+static inline int isolate_hugetlb(struct page *page, struct list_head *list)
{
- return false;
+ return -EBUSY;
}
static inline int get_hwpoison_huge_page(struct page *page, bool *hugetlb)
--- a/mm/gup.c~mm-migration-return-errno-when-isolate_huge_page-failed
+++ a/mm/gup.c
@@ -1930,7 +1930,7 @@ static long check_and_migrate_movable_pa
* Try to move out any movable page before pinning the range.
*/
if (folio_test_hugetlb(folio)) {
- if (!isolate_huge_page(&folio->page,
+ if (isolate_hugetlb(&folio->page,
&movable_page_list))
isolation_error_count++;
continue;
--- a/mm/hugetlb.c~mm-migration-return-errno-when-isolate_huge_page-failed
+++ a/mm/hugetlb.c
@@ -2765,8 +2765,7 @@ retry:
* Fail with -EBUSY if not possible.
*/
spin_unlock_irq(&hugetlb_lock);
- if (!isolate_huge_page(old_page, list))
- ret = -EBUSY;
+ ret = isolate_hugetlb(old_page, list);
spin_lock_irq(&hugetlb_lock);
goto free_new;
} else if (!HPageFreed(old_page)) {
@@ -2842,7 +2841,7 @@ int isolate_or_dissolve_huge_page(struct
if (hstate_is_gigantic(h))
return -ENOMEM;
- if (page_count(head) && isolate_huge_page(head, list))
+ if (page_count(head) && !isolate_hugetlb(head, list))
ret = 0;
else if (!page_count(head))
ret = alloc_and_dissolve_huge_page(h, head, list);
@@ -6952,15 +6951,15 @@ follow_huge_pgd(struct mm_struct *mm, un
return pte_page(*(pte_t *)pgd) + ((address & ~PGDIR_MASK) >> PAGE_SHIFT);
}
-bool isolate_huge_page(struct page *page, struct list_head *list)
+int isolate_hugetlb(struct page *page, struct list_head *list)
{
- bool ret = true;
+ int ret = 0;
spin_lock_irq(&hugetlb_lock);
if (!PageHeadHuge(page) ||
!HPageMigratable(page) ||
!get_page_unless_zero(page)) {
- ret = false;
+ ret = -EBUSY;
goto unlock;
}
ClearHPageMigratable(page);
--- a/mm/memory-failure.c~mm-migration-return-errno-when-isolate_huge_page-failed
+++ a/mm/memory-failure.c
@@ -2166,7 +2166,7 @@ static bool isolate_page(struct page *pa
bool lru = PageLRU(page);
if (PageHuge(page)) {
- isolated = isolate_huge_page(page, pagelist);
+ isolated = !isolate_hugetlb(page, pagelist);
} else {
if (lru)
isolated = !isolate_lru_page(page);
--- a/mm/memory_hotplug.c~mm-migration-return-errno-when-isolate_huge_page-failed
+++ a/mm/memory_hotplug.c
@@ -1643,7 +1643,7 @@ do_migrate_range(unsigned long start_pfn
if (PageHuge(page)) {
pfn = page_to_pfn(head) + compound_nr(head) - 1;
- isolate_huge_page(head, &source);
+ isolate_hugetlb(head, &source);
continue;
} else if (PageTransHuge(page))
pfn = page_to_pfn(head) + thp_nr_pages(page) - 1;
--- a/mm/mempolicy.c~mm-migration-return-errno-when-isolate_huge_page-failed
+++ a/mm/mempolicy.c
@@ -602,7 +602,7 @@ static int queue_pages_hugetlb(pte_t *pt
/* With MPOL_MF_MOVE, we migrate only unshared hugepage. */
if (flags & (MPOL_MF_MOVE_ALL) ||
(flags & MPOL_MF_MOVE && page_mapcount(page) == 1)) {
- if (!isolate_huge_page(page, qp->pagelist) &&
+ if (isolate_hugetlb(page, qp->pagelist) &&
(flags & MPOL_MF_STRICT))
/*
* Failed to isolate page but allow migrating pages
--- a/mm/migrate.c~mm-migration-return-errno-when-isolate_huge_page-failed
+++ a/mm/migrate.c
@@ -133,7 +133,7 @@ static void putback_movable_page(struct
*
* This function shall be used whenever the isolated pageset has been
* built from lru, balloon, hugetlbfs page. See isolate_migratepages_range()
- * and isolate_huge_page().
+ * and isolate_hugetlb().
*/
void putback_movable_pages(struct list_head *l)
{
@@ -1627,8 +1627,9 @@ static int add_page_for_migration(struct
if (PageHuge(page)) {
if (PageHead(page)) {
- isolate_huge_page(page, pagelist);
- err = 1;
+ err = isolate_hugetlb(page, pagelist);
+ if (!err)
+ err = 1;
}
} else {
struct page *head;
_
Patches currently in -mm which might be from linmiaohe@xxxxxxxxxx are
maintainers-add-maintainer-information-for-z3fold.patch
mm-shmemc-clean-up-comment-of-shmem_swapin_folio.patch
mm-reduce-the-rcu-lock-duration.patch
mm-migration-remove-unneeded-lock-page-and-pagemovable-check.patch
mm-migration-return-errno-when-isolate_huge_page-failed.patch
mm-migration-fix-potential-pte_unmap-on-an-not-mapped-pte.patch
