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Diffstat (limited to 'mm/page_cgroup.c')
-rw-r--r--mm/page_cgroup.c42
1 files changed, 42 insertions, 0 deletions
diff --git a/mm/page_cgroup.c b/mm/page_cgroup.c
index 3d535d594826..6c0081441a32 100644
--- a/mm/page_cgroup.c
+++ b/mm/page_cgroup.c
@@ -284,6 +284,7 @@ static DEFINE_MUTEX(swap_cgroup_mutex);
struct swap_cgroup_ctrl {
struct page **map;
unsigned long length;
+ spinlock_t lock;
};
struct swap_cgroup_ctrl swap_cgroup_ctrl[MAX_SWAPFILES];
@@ -335,6 +336,43 @@ not_enough_page:
}
/**
+ * swap_cgroup_cmpxchg - cmpxchg mem_cgroup's id for this swp_entry.
+ * @end: swap entry to be cmpxchged
+ * @old: old id
+ * @new: new id
+ *
+ * Returns old id at success, 0 at failure.
+ * (There is no mem_cgroup useing 0 as its id)
+ */
+unsigned short swap_cgroup_cmpxchg(swp_entry_t ent,
+ unsigned short old, unsigned short new)
+{
+ int type = swp_type(ent);
+ unsigned long offset = swp_offset(ent);
+ unsigned long idx = offset / SC_PER_PAGE;
+ unsigned long pos = offset & SC_POS_MASK;
+ struct swap_cgroup_ctrl *ctrl;
+ struct page *mappage;
+ struct swap_cgroup *sc;
+ unsigned long flags;
+ unsigned short retval;
+
+ ctrl = &swap_cgroup_ctrl[type];
+
+ mappage = ctrl->map[idx];
+ sc = page_address(mappage);
+ sc += pos;
+ spin_lock_irqsave(&ctrl->lock, flags);
+ retval = sc->id;
+ if (retval == old)
+ sc->id = new;
+ else
+ retval = 0;
+ spin_unlock_irqrestore(&ctrl->lock, flags);
+ return retval;
+}
+
+/**
* swap_cgroup_record - record mem_cgroup for this swp_entry.
* @ent: swap entry to be recorded into
* @mem: mem_cgroup to be recorded
@@ -352,14 +390,17 @@ unsigned short swap_cgroup_record(swp_entry_t ent, unsigned short id)
struct page *mappage;
struct swap_cgroup *sc;
unsigned short old;
+ unsigned long flags;
ctrl = &swap_cgroup_ctrl[type];
mappage = ctrl->map[idx];
sc = page_address(mappage);
sc += pos;
+ spin_lock_irqsave(&ctrl->lock, flags);
old = sc->id;
sc->id = id;
+ spin_unlock_irqrestore(&ctrl->lock, flags);
return old;
}
@@ -411,6 +452,7 @@ int swap_cgroup_swapon(int type, unsigned long max_pages)
mutex_lock(&swap_cgroup_mutex);
ctrl->length = length;
ctrl->map = array;
+ spin_lock_init(&ctrl->lock);
if (swap_cgroup_prepare(type)) {
/* memory shortage */
ctrl->map = NULL;