From: Konstantin Khlebnikov <k.khlebnikov@xxxxxxxxxxx>
3.12-stable review patch. If anyone has any objections, please let me know.
===============
commit 4d88e6f7d5ffc84e6094a47925870f4a130555c2 upstream.
If CONFIG_BALLOON_COMPACTION=n balloon_page_insert() does not link pages
with balloon and doesn't set PagePrivate flag, as a result
balloon_page_dequeue() cannot get any pages because it thinks that all
of them are isolated. Without balloon compaction nobody can isolate
ballooned pages. It's safe to remove this check.
Fixes: d6d86c0a7f8d ("mm/balloon_compaction: redesign ballooned pages management").
Signed-off-by: Konstantin Khlebnikov <k.khlebnikov@xxxxxxxxxxx>
Reported-by: Matt Mullins <mmullins@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Gavin Guo <gavin.guo@xxxxxxxxxxxxx>
Signed-off-by: Jiri Slaby <jslaby@xxxxxxx>
---
mm/balloon_compaction.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/mm/balloon_compaction.c b/mm/balloon_compaction.c
index d7aae638b585..2ad56effb962 100644
--- a/mm/balloon_compaction.c
+++ b/mm/balloon_compaction.c
@@ -93,11 +93,13 @@ struct page *balloon_page_dequeue(struct balloon_dev_info *b_dev_info)
* to be released by the balloon driver.
*/
if (trylock_page(page)) {
+#ifdef CONFIG_BALLOON_COMPACTION
if (!PagePrivate(page)) {
/* raced with isolation */
unlock_page(page);
continue;
}
+#endif
spin_lock_irqsave(&b_dev_info->pages_lock, flags);
balloon_page_delete(page);
spin_unlock_irqrestore(&b_dev_info->pages_lock, flags);
--
2.8.2
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