Merge branch 'master' of /repos/git/net-next-2.6

[pandora-kernel.git] / include / linux / page_cgroup.h

diff --git a/include/linux/page_cgroup.h b/include/linux/page_cgroup.h
index b02195d..6d6cb7a 100644 (file)
--- a/include/linux/page_cgroup.h
+++ b/include/linux/page_cgroup.h
@@ -35,12 +35,15 @@ struct page_cgroup *lookup_page_cgroup(struct page *page);
 
 enum {
        /* flags for mem_cgroup */
-       PCG_LOCK,  /* page cgroup is locked */
+       PCG_LOCK,  /* Lock for pc->mem_cgroup and following bits. */
        PCG_CACHE, /* charged as cache */
        PCG_USED, /* this object is in use. */
-       PCG_ACCT_LRU, /* page has been accounted for */
-       PCG_FILE_MAPPED, /* page is accounted as "mapped" */
        PCG_MIGRATION, /* under page migration */
+       /* flags for mem_cgroup and file and I/O status */
+       PCG_MOVE_LOCK, /* For race between move_account v.s. following bits */
+       PCG_FILE_MAPPED, /* page is accounted as "mapped" */
+       /* No lock in page_cgroup */
+       PCG_ACCT_LRU, /* page has been accounted for (under lru_lock) */
 };
 
 #define TESTPCGFLAG(uname, lname)                      \
@@ -94,6 +97,10 @@ static inline enum zone_type page_cgroup_zid(struct page_cgroup *pc)
 
 static inline void lock_page_cgroup(struct page_cgroup *pc)
 {
+       /*
+        * Don't take this lock in IRQ context.
+        * This lock is for pc->mem_cgroup, USED, CACHE, MIGRATION
+        */
        bit_spin_lock(PCG_LOCK, &pc->flags);
 }
 
@@ -107,6 +114,24 @@ static inline int page_is_cgroup_locked(struct page_cgroup *pc)
        return bit_spin_is_locked(PCG_LOCK, &pc->flags);
 }
 
+static inline void move_lock_page_cgroup(struct page_cgroup *pc,
+       unsigned long *flags)
+{
+       /*
+        * We know updates to pc->flags of page cache's stats are from both of
+        * usual context or IRQ context. Disable IRQ to avoid deadlock.
+        */
+       local_irq_save(*flags);
+       bit_spin_lock(PCG_MOVE_LOCK, &pc->flags);
+}
+
+static inline void move_unlock_page_cgroup(struct page_cgroup *pc,
+       unsigned long *flags)
+{
+       bit_spin_unlock(PCG_MOVE_LOCK, &pc->flags);
+       local_irq_restore(*flags);
+}
+
 #else /* CONFIG_CGROUP_MEM_RES_CTLR */
 struct page_cgroup;