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Commit c9ec5d7c authored by Mike Snitzer's avatar Mike Snitzer
Browse files

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: default avatarMike Snitzer <snitzer@redhat.com>
Signed-off-by: default avatarAlasdair G Kergon <agk@redhat.com>
Acked-by: default avatarJoe Thornber <ejt@redhat.com>
parent f6109372

drivers/md/dm-cache-target.c

+15 −15
Original line number Diff line number Diff line
@@ -103,6 +103,8 @@ struct cache { 
	struct dm_target *ti;

	struct dm_target_callbacks callbacks;



	struct dm_cache_metadata *cmd;



	/*

	 * Metadata is written to this device.

	 */
@@ -118,11 +120,6 @@ struct cache { 
	 */

	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.

	 */
@@ -140,8 +137,6 @@ struct cache { 
	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 cache { 
	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 @@ struct cache { 
	/*

	 * 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 @@ struct cache { 
	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 {