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Diffstat (limited to 'mm')
-rw-r--r--mm/balloon_compaction.c26
-rw-r--r--mm/compaction.c2
-rw-r--r--mm/migrate.c16
3 files changed, 17 insertions, 27 deletions
diff --git a/mm/balloon_compaction.c b/mm/balloon_compaction.c
index 6e45a5074bf0..52abeeb3cb9d 100644
--- a/mm/balloon_compaction.c
+++ b/mm/balloon_compaction.c
@@ -93,17 +93,12 @@ struct page *balloon_page_dequeue(struct balloon_dev_info *b_dev_info)
* to be released by the balloon driver.
*/
if (trylock_page(page)) {
+ if (!PagePrivate(page)) {
+ /* raced with isolation */
+ unlock_page(page);
+ continue;
+ }
spin_lock_irqsave(&b_dev_info->pages_lock, flags);
- /*
- * Raise the page refcount here to prevent any wrong
- * attempt to isolate this page, in case of coliding
- * with balloon_page_isolate() just after we release
- * the page lock.
- *
- * balloon_page_free() will take care of dropping
- * this extra refcount later.
- */
- get_page(page);
balloon_page_delete(page);
spin_unlock_irqrestore(&b_dev_info->pages_lock, flags);
unlock_page(page);
@@ -187,7 +182,9 @@ static inline void __isolate_balloon_page(struct page *page)
{
struct balloon_dev_info *b_dev_info = page->mapping->private_data;
unsigned long flags;
+
spin_lock_irqsave(&b_dev_info->pages_lock, flags);
+ ClearPagePrivate(page);
list_del(&page->lru);
b_dev_info->isolated_pages++;
spin_unlock_irqrestore(&b_dev_info->pages_lock, flags);
@@ -197,7 +194,9 @@ static inline void __putback_balloon_page(struct page *page)
{
struct balloon_dev_info *b_dev_info = page->mapping->private_data;
unsigned long flags;
+
spin_lock_irqsave(&b_dev_info->pages_lock, flags);
+ SetPagePrivate(page);
list_add(&page->lru, &b_dev_info->pages);
b_dev_info->isolated_pages--;
spin_unlock_irqrestore(&b_dev_info->pages_lock, flags);
@@ -235,12 +234,11 @@ bool balloon_page_isolate(struct page *page)
*/
if (likely(trylock_page(page))) {
/*
- * A ballooned page, by default, has just one refcount.
+ * A ballooned page, by default, has PagePrivate set.
* Prevent concurrent compaction threads from isolating
- * an already isolated balloon page by refcount check.
+ * an already isolated balloon page by clearing it.
*/
- if (__is_movable_balloon_page(page) &&
- page_count(page) == 2) {
+ if (balloon_page_movable(page)) {
__isolate_balloon_page(page);
unlock_page(page);
return true;
diff --git a/mm/compaction.c b/mm/compaction.c
index b9972c0fd917..edba18aed173 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -640,7 +640,7 @@ isolate_migratepages_block(struct compact_control *cc, unsigned long low_pfn,
*/
if (!PageLRU(page)) {
if (unlikely(balloon_page_movable(page))) {
- if (locked && balloon_page_isolate(page)) {
+ if (balloon_page_isolate(page)) {
/* Successfully isolated */
goto isolate_success;
}
diff --git a/mm/migrate.c b/mm/migrate.c
index 2740360cd216..01439953abf5 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -876,7 +876,7 @@ static int __unmap_and_move(struct page *page, struct page *newpage,
}
}
- if (unlikely(balloon_page_movable(page))) {
+ if (unlikely(isolated_balloon_page(page))) {
/*
* A ballooned page does not need any special attention from
* physical to virtual reverse mapping procedures.
@@ -955,17 +955,6 @@ static int unmap_and_move(new_page_t get_new_page, free_page_t put_new_page,
rc = __unmap_and_move(page, newpage, force, mode);
- if (unlikely(rc == MIGRATEPAGE_BALLOON_SUCCESS)) {
- /*
- * A ballooned page has been migrated already.
- * Now, it's the time to wrap-up counters,
- * handle the page back to Buddy and return.
- */
- dec_zone_page_state(page, NR_ISOLATED_ANON +
- page_is_file_cache(page));
- balloon_page_free(page);
- return MIGRATEPAGE_SUCCESS;
- }
out:
if (rc != -EAGAIN) {
/*
@@ -988,6 +977,9 @@ out:
if (rc != MIGRATEPAGE_SUCCESS && put_new_page) {
ClearPageSwapBacked(newpage);
put_new_page(newpage, private);
+ } else if (unlikely(__is_movable_balloon_page(newpage))) {
+ /* drop our reference, page already in the balloon */
+ put_page(newpage);
} else
putback_lru_page(newpage);