dm: optimize reorder structure
This reorder actually improves performance by 20% (from 39.1s to 32.8s)
on x86-64 quad core Opteron.
I have no explanation for this, possibly it makes some other entries are
better cache-aligned.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index ecff83f..9e39d2b 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -133,6 +133,13 @@
atomic_t holders;
atomic_t open_count;
+ /*
+ * The current mapping.
+ * Use dm_get_live_table{_fast} or take suspend_lock for
+ * dereference.
+ */
+ struct dm_table *map;
+
unsigned long flags;
struct request_queue *queue;
@@ -162,13 +169,6 @@
struct workqueue_struct *wq;
/*
- * The current mapping.
- * Use dm_get_live_table{_fast} or take suspend_lock for
- * dereference.
- */
- struct dm_table *map;
-
- /*
* io objects are allocated from here.
*/
mempool_t *io_pool;