mm/migration: return errno when isolate_huge_page failed

[ Upstream commit 7ce82f4c3f3ead13a9d9498768e3b1a79975c4d8 ]

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@huawei.com
Fixes: e8db67eb0ded ("mm: migrate: move_pages() supports thp migration")
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Suggested-by: Huang Ying <ying.huang@intel.com>
Reported-by: kernel test robot <lkp@intel.com> (build error)
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Peter Xu <peterx@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Stable-dep-of: 73bdf65ea748 ("migrate: hugetlb: check for hugetlb shared PMD in node migration")
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
index a18fc8e5a3ddb8051a2ec43bcf8201e9f3d6dbdb..c0ba379574a46e499ea9f1c122bd3fae8b7f4140 100644 (file)
--- a/include/linux/hugetlb.h
+++ b/include/linux/hugetlb.h
@@ -145,7 +145,7 @@ int 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);
 void putback_active_hugepage(struct page *page);
 void move_hugetlb_state(struct page *oldpage, struct page *newpage, int reason);
 void free_huge_page(struct page *page);
@@ -326,9 +326,9 @@ 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 void putback_active_hugepage(struct page *page)

diff --git a/mm/gup.c b/mm/gup.c
index 6d5e4fd55d320a13074c5b994ef5b081e66e1981..11307a8b20d5847abc97191c21520c86585fc433 100644 (file)
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -1627,7 +1627,7 @@ check_again:
                 */
                if (is_migrate_cma_page(head)) {
                        if (PageHuge(head)) {
-                               if (!isolate_huge_page(head, &cma_page_list))
+                               if (isolate_hugetlb(head, &cma_page_list))
                                        isolation_error_count++;
                        } else {
                                if (!PageLRU(head) && drain_allow) {

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 3499b3803384b81cbc3c4deabfcbd0600f8e23e1..81949f6d29af5e84791e8aa98d49438cab08dc03 100644 (file)
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -5655,14 +5655,14 @@ 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(&hugetlb_lock);
        if (!PageHeadHuge(page) || !page_huge_active(page) ||
            !get_page_unless_zero(page)) {
-               ret = false;
+               ret = -EBUSY;
                goto unlock;
        }
        clear_page_huge_active(page);

diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index aef267c6a7246369a799b296162a37a9f69a0f87..b21dd4a7939260d8f075533fc28690865b946a83 100644 (file)
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -1763,7 +1763,7 @@ 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 6275b1c05f111276e7289516aac3a42e1e02a1f5..f0633f9a911660a5398475a13b8d423c3908a2dd 100644 (file)
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -1288,7 +1288,7 @@ 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 f9f47449e8ddadeb69686661ac5ad6a7ca4e31a8..59d72b121346f087e7e8b38157e2d63fdbce5348 100644 (file)
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -623,7 +623,7 @@ 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 b716b8fa2c3ff715d5db7816f95ba8f2335ebae2..fcb7eb6a6ecae56524671da47fe8b26fef8e3b60 100644 (file)
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -164,7 +164,7 @@ 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)
 {
@@ -1657,8 +1657,9 @@ 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;