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-rw-r--r--mm/rmap.c39
1 files changed, 22 insertions, 17 deletions
diff --git a/mm/rmap.c b/mm/rmap.c
index 795f9d5f8386..b9eb5c12f3fe 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -1440,21 +1440,20 @@ static bool try_to_unmap_one(struct page *page, struct vm_area_struct *vma,
/*
* If the page is mlock()d, we cannot swap it out.
*/
- if (!(flags & TTU_IGNORE_MLOCK)) {
- if (vma->vm_flags & VM_LOCKED) {
- /* PTE-mapped THP are never marked as mlocked */
- if (!PageTransCompound(page) ||
- (PageHead(page) && !PageDoubleMap(page))) {
- /*
- * Holding pte lock, we do *not* need
- * mmap_lock here
- */
- mlock_vma_page(page);
- }
- ret = false;
- page_vma_mapped_walk_done(&pvmw);
- break;
- }
+ if (!(flags & TTU_IGNORE_MLOCK) &&
+ (vma->vm_flags & VM_LOCKED)) {
+ /*
+ * PTE-mapped THP are never marked as mlocked: so do
+ * not set it on a DoubleMap THP, nor on an Anon THP
+ * (which may still be PTE-mapped after DoubleMap was
+ * cleared). But stop unmapping even in those cases.
+ */
+ if (!PageTransCompound(page) || (PageHead(page) &&
+ !PageDoubleMap(page) && !PageAnon(page)))
+ mlock_vma_page(page);
+ page_vma_mapped_walk_done(&pvmw);
+ ret = false;
+ break;
}
/* Unexpected PMD-mapped THP? */
@@ -1986,8 +1985,10 @@ static bool page_mlock_one(struct page *page, struct vm_area_struct *vma,
*/
if (vma->vm_flags & VM_LOCKED) {
/*
- * PTE-mapped THP are never marked as mlocked, but
- * this function is never called when PageDoubleMap().
+ * PTE-mapped THP are never marked as mlocked; but
+ * this function is never called on a DoubleMap THP,
+ * nor on an Anon THP (which may still be PTE-mapped
+ * after DoubleMap was cleared).
*/
mlock_vma_page(page);
/*
@@ -2022,6 +2023,10 @@ void page_mlock(struct page *page)
VM_BUG_ON_PAGE(!PageLocked(page) || PageLRU(page), page);
VM_BUG_ON_PAGE(PageCompound(page) && PageDoubleMap(page), page);
+ /* Anon THP are only marked as mlocked when singly mapped */
+ if (PageTransCompound(page) && PageAnon(page))
+ return;
+
rmap_walk(page, &rwc);
}