[PATCH RFC 11/15] mm: handle book relock in memory controller

[Konstantin Khlebnikov <khlebnikov@openvz.org>]

Carefully relock book lru lock at page memory cgroup change.

Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org>
---
 mm/memcontrol.c |    8 +++-----
 1 files changed, 3 insertions(+), 5 deletions(-)

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 84e04ae..90e21d2 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -2535,7 +2535,6 @@ __mem_cgroup_commit_charge_lrucare(struct page *page, struct mem_cgroup *memcg,
 					enum charge_type ctype)
 {
 	struct page_cgroup *pc = lookup_page_cgroup(page);
-	struct zone *zone = page_zone(page);
 	struct book *book;
 	unsigned long flags;
 	bool removed = false;
@@ -2545,20 +2544,19 @@ __mem_cgroup_commit_charge_lrucare(struct page *page, struct mem_cgroup *memcg,
 	 * is already on LRU. It means the page may on some other page_cgroup's
 	 * LRU. Take care of it.
 	 */
-	spin_lock_irqsave(&zone->lru_lock, flags);
+	book = lock_page_book(page, &flags);
 	if (PageLRU(page)) {
-		book = page_book(page);
 		del_page_from_lru_list(book, page, page_lru(page));
 		ClearPageLRU(page);
 		removed = true;
 	}
 	__mem_cgroup_commit_charge(memcg, page, 1, pc, ctype);
 	if (removed) {
-		book = page_book(page);
+		book = __relock_page_book(book, page);
 		add_page_to_lru_list(book, page, page_lru(page));
 		SetPageLRU(page);
 	}
-	spin_unlock_irqrestore(&zone->lru_lock, flags);
+	unlock_book(book, &flags);
 	return;
 }
 

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