diff options
| author | Jens Axboe <axboe@fb.com> | 2016-08-25 08:00:28 -0600 |
|---|---|---|
| committer | Jens Axboe <axboe@fb.com> | 2016-08-29 08:13:21 -0600 |
| commit | 8d354f133e86dd03ea7885a91df398c55ff699ff (patch) | |
| tree | 11049556188d8274f98553f924fda66f0754621e /include | |
| parent | 27489a3c827b7eebba26eda0320bb0f100bef167 (diff) | |
| download | linux-8d354f133e86dd03ea7885a91df398c55ff699ff.tar.bz2 | |
blk-mq: improve layout of blk_mq_hw_ctx
Various cache line optimizations:
- Move delay_work towards the end. It's huge, and we don't use it
a lot (only SCSI).
- Move the atomic state into the same cacheline as the the dispatch
list and lock.
- Rearrange a few members to pack it better.
- Shrink the max-order for dispatch accounting from 10 to 7. This
means that ->dispatched[] and ->run now take up their own
cacheline.
This shrinks struct blk_mq_hw_ctx down to 8 cachelines.
Signed-off-by: Jens Axboe <axboe@fb.com>
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/blk-mq.h | 9 |
1 files changed, 5 insertions, 4 deletions
diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h index d579252e6463..e1544f0f8c21 100644 --- a/include/linux/blk-mq.h +++ b/include/linux/blk-mq.h @@ -22,11 +22,10 @@ struct blk_mq_hw_ctx { struct { spinlock_t lock; struct list_head dispatch; + unsigned long state; /* BLK_MQ_S_* flags */ } ____cacheline_aligned_in_smp; - unsigned long state; /* BLK_MQ_S_* flags */ struct work_struct run_work; - struct delayed_work delay_work; cpumask_var_t cpumask; int next_cpu; int next_cpu_batch; @@ -40,8 +39,8 @@ struct blk_mq_hw_ctx { struct blk_mq_ctxmap ctx_map; - unsigned int nr_ctx; struct blk_mq_ctx **ctxs; + unsigned int nr_ctx; atomic_t wait_index; @@ -49,7 +48,7 @@ struct blk_mq_hw_ctx { unsigned long queued; unsigned long run; -#define BLK_MQ_MAX_DISPATCH_ORDER 10 +#define BLK_MQ_MAX_DISPATCH_ORDER 7 unsigned long dispatched[BLK_MQ_MAX_DISPATCH_ORDER]; unsigned int numa_node; @@ -57,6 +56,8 @@ struct blk_mq_hw_ctx { atomic_t nr_active; + struct delayed_work delay_work; + struct blk_mq_cpu_notifier cpu_notifier; struct kobject kobj; |