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Date: Mon, 30 May 2022 19:30:15 +0800
From: Miaohe Lin <linmiaohe@...wei.com>
To: <akpm@...ux-foundation.org>, <naoya.horiguchi@....com>
CC: <peterx@...hat.com>, <apopple@...dia.com>, <ying.huang@...el.com>,
<osalvador@...e.de>, <mike.kravetz@...cle.com>,
<songmuchun@...edance.com>, <hch@....de>, <dhowells@...hat.com>,
<cl@...ux.com>, <linux-mm@...ck.org>,
<linux-kernel@...r.kernel.org>, <linmiaohe@...wei.com>
Subject: [PATCH v4 3/4] mm/migration: return errno when isolate_huge_page failed
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.
Fixes: e8db67eb0ded ("mm: migrate: move_pages() supports thp migration")
Suggested-by: Huang Ying <ying.huang@...el.com>
Signed-off-by: Miaohe Lin <linmiaohe@...wei.com>
Reported-by: kernel test robot <lkp@...el.com> (build error)
---
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(-)
diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
index e4cff27d1198..756b66ff025e 100644
--- a/include/linux/hugetlb.h
+++ b/include/linux/hugetlb.h
@@ -170,7 +170,7 @@ bool hugetlb_reserve_pages(struct inode *inode, long from, long to,
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(struct mm_struct *mm, unsigned long addr,
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)
diff --git a/mm/gup.c b/mm/gup.c
index 551264407624..3899dcb288a6 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -1898,7 +1898,7 @@ static long check_and_migrate_movable_pages(unsigned long nr_pages,
* 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;
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 7c468ac1d069..65ab215b39ee 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -2765,8 +2765,7 @@ static int alloc_and_dissolve_huge_page(struct hstate *h, struct page *old_page,
* 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 page *page, struct list_head *list)
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, unsigned long address, pgd_t *pgd, int fla
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);
diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index b85661cbdc4a..5deb1b1cb2fd 100644
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -2166,7 +2166,7 @@ static bool isolate_page(struct page *page, struct list_head *pagelist)
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);
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index 1213d0c67a53..649a50ed90f3 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -1643,7 +1643,7 @@ do_migrate_range(unsigned long start_pfn, unsigned long end_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;
diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index 2dad094177bf..f96d55131689 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -602,7 +602,7 @@ static int queue_pages_hugetlb(pte_t *pte, unsigned long hmask,
/* 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
diff --git a/mm/migrate.c b/mm/migrate.c
index 337336115e43..a14c6d5ceafc 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -133,7 +133,7 @@ static void putback_movable_page(struct page *page)
*
* 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 mm_struct *mm, unsigned long addr,
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;
--
2.23.0
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