summaryrefslogtreecommitdiff
path: root/mm/migrate.c
diff options
context:
space:
mode:
Diffstat (limited to 'mm/migrate.c')
-rw-r--r--mm/migrate.c48
1 files changed, 33 insertions, 15 deletions
diff --git a/mm/migrate.c b/mm/migrate.c
index 7d2983f3783e..89e5c3fe8bbc 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -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;
@@ -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;
/*
@@ -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);
}
@@ -757,7 +775,7 @@ 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);
@@ -850,7 +868,7 @@ 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);