From: Huang Ying <ying.hu...@intel.com>
To improve the code readability.
Signed-off-by: "Huang, Ying" <ying.hu...@intel.com>
Suggested-by: Dave Hansen <dave.han...@linux.intel.com>
Cc: Michal Hocko <mho...@suse.com>
Cc: Johannes Weiner <han...@cmpxchg.org>
Cc: Shaohua Li <s...@kernel.org>
Cc: Hugh Dickins <hu...@google.com>
Cc: Minchan Kim <minc...@kernel.org>
Cc: Rik van Riel <r...@redhat.com>
Cc: Daniel Jordan <daniel.m.jor...@oracle.com>
Cc: Dan Williams <dan.j.willi...@intel.com>
---
mm/swapfile.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/mm/swapfile.c b/mm/swapfile.c
index d8fddfb000ec..e31aa601d9c0 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -297,6 +297,12 @@ static inline void unlock_cluster(struct swap_cluster_info
*ci)
spin_unlock(&ci->lock);
}
+/*
+ * At most times, fine grained cluster lock is sufficient to protect
+ * the operations on sis->swap_map. No need to acquire gross grained
+ * sis->lock. But cluster and cluster lock isn't available for HDD,
+ * so sis->lock will be instead for them.
+ */
static inline struct swap_cluster_info *lock_cluster_or_swap_info(
struct swap_info_struct *si,
unsigned long offset)
--
2.16.4
