From 032482fda4d19e0de10e0e99420a616c1e3e7820 Mon Sep 17 00:00:00 2001 From: Mike Snitzer Date: Mon, 22 Feb 2016 15:27:50 -0500 Subject: [PATCH] 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 --- drivers/md/dm.c | 34 ++++++++++++++++++---------------- 1 file 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) @@ -178,33 +191,22 @@ 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; -- GitLab