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authorMike Snitzer <snitzer@redhat.com>2016-02-22 23:27:50 +0300
committerMike Snitzer <snitzer@redhat.com>2016-03-11 01:12:07 +0300
commit032482fda4d19e0de10e0e99420a616c1e3e7820 (patch)
tree32c11b7344e9027f56351e1d98b0fa57d8abbf14 /drivers/md
parent1d3aa6f683b1c1a813a63339d7309cff58ba4531 (diff)
downloadlinux-032482fda4d19e0de10e0e99420a616c1e3e7820.tar.xz
dm: reorder 'struct mapped_device' members to fix alignment and holes
Saves 16 bytes by eliminating 4 4byte holes but more importantly: numerous members that crossed cachelines were fixed. Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Diffstat (limited to 'drivers/md')
-rw-r--r--drivers/md/dm.c34
1 files changed, 18 insertions, 16 deletions
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 3cae8547420a..503988ff66ea 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -126,8 +126,6 @@ struct dm_rq_clone_bio_info {
struct mapped_device {
struct srcu_struct io_barrier;
struct mutex suspend_lock;
- atomic_t holders;
- atomic_t open_count;
/*
* The current mapping (struct dm_table *).
@@ -148,6 +146,9 @@ struct mapped_device {
/* Protect queue and type against concurrent access. */
struct mutex type_lock;
+ atomic_t holders;
+ atomic_t open_count;
+
struct dm_target *immutable_target;
struct target_type *immutable_target_type;
@@ -162,8 +163,20 @@ struct mapped_device {
atomic_t pending[2];
wait_queue_head_t wait;
struct work_struct work;
- struct bio_list deferred;
spinlock_t deferred_lock;
+ struct bio_list deferred;
+
+ /*
+ * Event handling.
+ */
+ wait_queue_head_t eventq;
+ atomic_t event_nr;
+ atomic_t uevent_seq;
+ struct list_head uevent_list;
+ spinlock_t uevent_lock; /* Protect access to uevent_list */
+
+ /* the number of internal suspends */
+ unsigned internal_suspend_count;
/*
* Processing queue (flush)
@@ -179,32 +192,21 @@ struct mapped_device {
struct bio_set *bs;
/*
- * Event handling.
- */
- atomic_t event_nr;
- wait_queue_head_t eventq;
- atomic_t uevent_seq;
- struct list_head uevent_list;
- spinlock_t uevent_lock; /* Protect access to uevent_list */
-
- /*
* freeze/thaw support require holding onto a super block
*/
struct super_block *frozen_sb;
- struct block_device *bdev;
/* forced geometry settings */
struct hd_geometry geometry;
+ struct block_device *bdev;
+
/* kobject and completion */
struct dm_kobject_holder kobj_holder;
/* zero-length flush that will be cloned and submitted to targets */
struct bio flush_bio;
- /* the number of internal suspends */
- unsigned internal_suspend_count;
-
struct dm_stats stats;
struct kthread_worker kworker;