blk-mq: Reduce blk_mq_hw_ctx size
Since the srcu structure is rather large (184 bytes on an x86-64
system with kernel debugging disabled), only allocate it if needed.
Reported-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Cc: Hannes Reinecke <hare@suse.com>
Cc: Omar Sandoval <osandov@fb.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h
index f1bd13a..3f2c22a 100644
--- a/include/linux/blk-mq.h
+++ b/include/linux/blk-mq.h
@@ -39,8 +39,6 @@
struct blk_mq_tags *tags;
struct blk_mq_tags *sched_tags;
- struct srcu_struct queue_rq_srcu;
-
unsigned long queued;
unsigned long run;
#define BLK_MQ_MAX_DISPATCH_ORDER 7
@@ -62,6 +60,9 @@
struct dentry *debugfs_dir;
struct dentry *sched_debugfs_dir;
#endif
+
+ /* Must be the last member - see also blk_mq_hw_ctx_size(). */
+ struct srcu_struct queue_rq_srcu[0];
};
struct blk_mq_tag_set {