dm cache: eliminate holes in cache structure
Reorder members in the cache structure to eliminate 6 out of 7 holes
(reclaiming 24 bytes). Also, the 'worker' and 'waker' members no longer
straddle cachelines.
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Acked-by: Joe Thornber <ejt@redhat.com>
diff --git a/drivers/md/dm-cache-target.c b/drivers/md/dm-cache-target.c
index 22ff650..2956976 100644
--- a/drivers/md/dm-cache-target.c
+++ b/drivers/md/dm-cache-target.c
@@ -103,6 +103,8 @@
struct dm_target *ti;
struct dm_target_callbacks callbacks;
+ struct dm_cache_metadata *cmd;
+
/*
* Metadata is written to this device.
*/
@@ -119,11 +121,6 @@
struct dm_dev *cache_dev;
/*
- * Cache features such as write-through.
- */
- struct cache_features features;
-
- /*
* Size of the origin device in _complete_ blocks and native sectors.
*/
dm_oblock_t origin_blocks;
@@ -140,8 +137,6 @@
uint32_t sectors_per_block;
int sectors_per_block_shift;
- struct dm_cache_metadata *cmd;
-
spinlock_t lock;
struct bio_list deferred_bios;
struct bio_list deferred_flush_bios;
@@ -150,8 +145,8 @@
struct list_head completed_migrations;
struct list_head need_commit_migrations;
sector_t migration_threshold;
- atomic_t nr_migrations;
wait_queue_head_t migration_wait;
+ atomic_t nr_migrations;
/*
* cache_size entries, dirty if set
@@ -162,9 +157,16 @@
/*
* origin_blocks entries, discarded if set.
*/
- uint32_t discard_block_size; /* a power of 2 times sectors per block */
dm_dblock_t discard_nr_blocks;
unsigned long *discard_bitset;
+ uint32_t discard_block_size; /* a power of 2 times sectors per block */
+
+ /*
+ * Rather than reconstructing the table line for the status we just
+ * save it and regurgitate.
+ */
+ unsigned nr_ctr_args;
+ const char **ctr_args;
struct dm_kcopyd_client *copier;
struct workqueue_struct *wq;
@@ -189,14 +191,12 @@
bool loaded_mappings:1;
bool loaded_discards:1;
- struct cache_stats stats;
-
/*
- * Rather than reconstructing the table line for the status we just
- * save it and regurgitate.
+ * Cache features such as write-through.
*/
- unsigned nr_ctr_args;
- const char **ctr_args;
+ struct cache_features features;
+
+ struct cache_stats stats;
};
struct per_bio_data {