dm: adjust structure members to improve alignment
Eliminate most holes in DM data structures that were modified by
commit 6f1c819c21 ("dm: convert to bioset_init()/mempool_init()").
Also prevent structure members from unnecessarily spanning cache
lines.
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
diff --git a/drivers/md/dm-cache-target.c b/drivers/md/dm-cache-target.c
index 001c712..ce14a3d 100644
--- a/drivers/md/dm-cache-target.c
+++ b/drivers/md/dm-cache-target.c
@@ -371,7 +371,13 @@ struct cache_stats {
struct cache {
struct dm_target *ti;
- struct dm_target_callbacks callbacks;
+ spinlock_t lock;
+
+ /*
+ * Fields for converting from sectors to blocks.
+ */
+ int sectors_per_block_shift;
+ sector_t sectors_per_block;
struct dm_cache_metadata *cmd;
@@ -402,13 +408,11 @@ struct cache {
dm_cblock_t cache_size;
/*
- * Fields for converting from sectors to blocks.
+ * Invalidation fields.
*/
- sector_t sectors_per_block;
- int sectors_per_block_shift;
+ spinlock_t invalidation_lock;
+ struct list_head invalidation_requests;
- spinlock_t lock;
- struct bio_list deferred_bios;
sector_t migration_threshold;
wait_queue_head_t migration_wait;
atomic_t nr_allocated_migrations;
@@ -419,13 +423,11 @@ struct cache {
*/
atomic_t nr_io_migrations;
+ struct bio_list deferred_bios;
+
struct rw_semaphore quiesce_lock;
- /*
- * cache_size entries, dirty if set
- */
- atomic_t nr_dirty;
- unsigned long *dirty_bitset;
+ struct dm_target_callbacks callbacks;
/*
* origin_blocks entries, discarded if set.
@@ -442,24 +444,20 @@ struct cache {
const char **ctr_args;
struct dm_kcopyd_client *copier;
- struct workqueue_struct *wq;
struct work_struct deferred_bio_worker;
struct work_struct migration_worker;
+ struct workqueue_struct *wq;
struct delayed_work waker;
struct dm_bio_prison_v2 *prison;
- struct bio_set bs;
- mempool_t migration_pool;
+ /*
+ * cache_size entries, dirty if set
+ */
+ unsigned long *dirty_bitset;
+ atomic_t nr_dirty;
- struct dm_cache_policy *policy;
unsigned policy_nr_args;
-
- bool need_tick_bio:1;
- bool sized:1;
- bool invalidate:1;
- bool commit_requested:1;
- bool loaded_mappings:1;
- bool loaded_discards:1;
+ struct dm_cache_policy *policy;
/*
* Cache features such as write-through.
@@ -468,18 +466,23 @@ struct cache {
struct cache_stats stats;
- /*
- * Invalidation fields.
- */
- spinlock_t invalidation_lock;
- struct list_head invalidation_requests;
+ bool need_tick_bio:1;
+ bool sized:1;
+ bool invalidate:1;
+ bool commit_requested:1;
+ bool loaded_mappings:1;
+ bool loaded_discards:1;
+
+ struct rw_semaphore background_work_lock;
+
+ struct batcher committer;
+ struct work_struct commit_ws;
struct io_tracker tracker;
- struct work_struct commit_ws;
- struct batcher committer;
+ mempool_t migration_pool;
- struct rw_semaphore background_work_lock;
+ struct bio_set bs;
};
struct per_bio_data {