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-rw-r--r--mm/rmap.c66
1 files changed, 49 insertions, 17 deletions
diff --git a/mm/rmap.c b/mm/rmap.c
index b9986c8db524..73c0ff1c73ab 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -1411,10 +1411,6 @@ static bool try_to_unmap_one(struct page *page, struct vm_area_struct *vma,
if (flags & TTU_SYNC)
pvmw.flags = PVMW_SYNC;
- /* munlock has nothing to gain from examining un-locked vmas */
- if ((flags & TTU_MUNLOCK) && !(vma->vm_flags & VM_LOCKED))
- return true;
-
if (IS_ENABLED(CONFIG_MIGRATION) && (flags & TTU_MIGRATION) &&
is_zone_device_page(page) && !is_device_private_page(page))
return true;
@@ -1476,8 +1472,6 @@ static bool try_to_unmap_one(struct page *page, struct vm_area_struct *vma,
page_vma_mapped_walk_done(&pvmw);
break;
}
- if (flags & TTU_MUNLOCK)
- continue;
}
/* Unexpected PMD-mapped THP? */
@@ -1790,20 +1784,58 @@ void try_to_unmap(struct page *page, enum ttu_flags flags)
rmap_walk(page, &rwc);
}
+/*
+ * Walks the vma's mapping a page and mlocks the page if any locked vma's are
+ * found. Once one is found the page is locked and the scan can be terminated.
+ */
+static bool page_mlock_one(struct page *page, struct vm_area_struct *vma,
+ unsigned long address, void *unused)
+{
+ struct page_vma_mapped_walk pvmw = {
+ .page = page,
+ .vma = vma,
+ .address = address,
+ };
+
+ /* An un-locked vma doesn't have any pages to lock, continue the scan */
+ if (!(vma->vm_flags & VM_LOCKED))
+ return true;
+
+ while (page_vma_mapped_walk(&pvmw)) {
+ /*
+ * Need to recheck under the ptl to serialise with
+ * __munlock_pagevec_fill() after VM_LOCKED is cleared in
+ * munlock_vma_pages_range().
+ */
+ if (vma->vm_flags & VM_LOCKED) {
+ /* PTE-mapped THP are never mlocked */
+ if (!PageTransCompound(page))
+ mlock_vma_page(page);
+ page_vma_mapped_walk_done(&pvmw);
+ }
+
+ /*
+ * no need to continue scanning other vma's if the page has
+ * been locked.
+ */
+ return false;
+ }
+
+ return true;
+}
+
/**
- * try_to_munlock - try to munlock a page
- * @page: the page to be munlocked
+ * page_mlock - try to mlock a page
+ * @page: the page to be mlocked
*
- * Called from munlock code. Checks all of the VMAs mapping the page
- * to make sure nobody else has this page mlocked. The page will be
- * returned with PG_mlocked cleared if no other vmas have it mlocked.
+ * Called from munlock code. Checks all of the VMAs mapping the page and mlocks
+ * the page if any are found. The page will be returned with PG_mlocked cleared
+ * if it is not mapped by any locked vmas.
*/
-
-void try_to_munlock(struct page *page)
+void page_mlock(struct page *page)
{
struct rmap_walk_control rwc = {
- .rmap_one = try_to_unmap_one,
- .arg = (void *)TTU_MUNLOCK,
+ .rmap_one = page_mlock_one,
.done = page_not_mapped,
.anon_lock = page_lock_anon_vma_read,
@@ -1855,7 +1887,7 @@ static struct anon_vma *rmap_walk_anon_lock(struct page *page,
* Find all the mappings of a page using the mapping pointer and the vma chains
* contained in the anon_vma struct it points to.
*
- * When called from try_to_munlock(), the mmap_lock of the mm containing the vma
+ * When called from page_mlock(), the mmap_lock of the mm containing the vma
* where the page was found will be held for write. So, we won't recheck
* vm_flags for that VMA. That should be OK, because that vma shouldn't be
* LOCKED.
@@ -1908,7 +1940,7 @@ static void rmap_walk_anon(struct page *page, struct rmap_walk_control *rwc,
* Find all the mappings of a page using the mapping pointer and the vma chains
* contained in the address_space struct it points to.
*
- * When called from try_to_munlock(), the mmap_lock of the mm containing the vma
+ * When called from page_mlock(), the mmap_lock of the mm containing the vma
* where the page was found will be held for write. So, we won't recheck
* vm_flags for that VMA. That should be OK, because that vma shouldn't be
* LOCKED.