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-rw-r--r--mm/migrate.c58
1 files changed, 38 insertions, 20 deletions
diff --git a/mm/migrate.c b/mm/migrate.c
index 352de555626c..34132f8e9109 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -375,7 +375,7 @@ void migrate_page_copy(struct page *newpage, struct page *page)
* redo the accounting that clear_page_dirty_for_io undid,
* but we can't use set_page_dirty because that function
* is actually a signal that all of the page has become dirty.
- * Wheras only part of our page may be dirty.
+ * Whereas only part of our page may be dirty.
*/
__set_page_dirty_nobuffers(newpage);
}
@@ -564,7 +564,7 @@ static int fallback_migrate_page(struct address_space *mapping,
* == 0 - success
*/
static int move_to_new_page(struct page *newpage, struct page *page,
- int remap_swapcache)
+ int remap_swapcache, bool sync)
{
struct address_space *mapping;
int rc;
@@ -586,18 +586,28 @@ static int move_to_new_page(struct page *newpage, struct page *page,
mapping = page_mapping(page);
if (!mapping)
rc = migrate_page(mapping, newpage, page);
- else if (mapping->a_ops->migratepage)
+ else {
/*
- * Most pages have a mapping and most filesystems
- * should provide a migration function. Anonymous
- * pages are part of swap space which also has its
- * own migration function. This is the most common
- * path for page migration.
+ * Do not writeback pages if !sync and migratepage is
+ * not pointing to migrate_page() which is nonblocking
+ * (swapcache/tmpfs uses migratepage = migrate_page).
*/
- rc = mapping->a_ops->migratepage(mapping,
- newpage, page);
- else
- rc = fallback_migrate_page(mapping, newpage, page);
+ if (PageDirty(page) && !sync &&
+ mapping->a_ops->migratepage != migrate_page)
+ rc = -EBUSY;
+ else if (mapping->a_ops->migratepage)
+ /*
+ * Most pages have a mapping and most filesystems
+ * should provide a migration function. Anonymous
+ * pages are part of swap space which also has its
+ * own migration function. This is the most common
+ * path for page migration.
+ */
+ rc = mapping->a_ops->migratepage(mapping,
+ newpage, page);
+ else
+ rc = fallback_migrate_page(mapping, newpage, page);
+ }
if (rc) {
newpage->mapping = NULL;
@@ -623,7 +633,7 @@ static int unmap_and_move(new_page_t get_new_page, unsigned long private,
struct page *newpage = get_new_page(page, private, &result);
int remap_swapcache = 1;
int charge = 0;
- struct mem_cgroup *mem = NULL;
+ struct mem_cgroup *mem;
struct anon_vma *anon_vma = NULL;
if (!newpage)
@@ -641,7 +651,7 @@ static int unmap_and_move(new_page_t get_new_page, unsigned long private,
rc = -EAGAIN;
if (!trylock_page(page)) {
- if (!force)
+ if (!force || !sync)
goto move_newpage;
/*
@@ -678,7 +688,7 @@ static int unmap_and_move(new_page_t get_new_page, unsigned long private,
}
/* charge against new page */
- charge = mem_cgroup_prepare_migration(page, newpage, &mem);
+ charge = mem_cgroup_prepare_migration(page, newpage, &mem, GFP_KERNEL);
if (charge == -ENOMEM) {
rc = -ENOMEM;
goto unlock;
@@ -686,7 +696,15 @@ static int unmap_and_move(new_page_t get_new_page, unsigned long private,
BUG_ON(charge);
if (PageWriteback(page)) {
- if (!force || !sync)
+ /*
+ * For !sync, there is no point retrying as the retry loop
+ * is expected to be too short for PageWriteback to be cleared
+ */
+ if (!sync) {
+ rc = -EBUSY;
+ goto uncharge;
+ }
+ if (!force)
goto uncharge;
wait_on_page_writeback(page);
}
@@ -757,14 +775,14 @@ static int unmap_and_move(new_page_t get_new_page, unsigned long private,
skip_unmap:
if (!page_mapped(page))
- rc = move_to_new_page(newpage, page, remap_swapcache);
+ rc = move_to_new_page(newpage, page, remap_swapcache, sync);
if (rc && remap_swapcache)
remove_migration_ptes(page, page);
/* Drop an anon_vma reference if we took one */
if (anon_vma)
- drop_anon_vma(anon_vma);
+ put_anon_vma(anon_vma);
uncharge:
if (!charge)
@@ -850,13 +868,13 @@ static int unmap_and_move_huge_page(new_page_t get_new_page,
try_to_unmap(hpage, TTU_MIGRATION|TTU_IGNORE_MLOCK|TTU_IGNORE_ACCESS);
if (!page_mapped(hpage))
- rc = move_to_new_page(new_hpage, hpage, 1);
+ rc = move_to_new_page(new_hpage, hpage, 1, sync);
if (rc)
remove_migration_ptes(hpage, hpage);
if (anon_vma)
- drop_anon_vma(anon_vma);
+ put_anon_vma(anon_vma);
out:
unlock_page(hpage);