On 6/18/23 09:07, Yu Kuai wrote:
Start tag fair sharing when a device start to issue io will waste
resources, same number of tags will be assigned to each disk/hctx,
and such tags can't be used for other disk/hctx, which means a disk/hctx
can't use more than assinged tags even if there are still lots of tags
^^^^^^^^
assigned
that is assinged to other disks are unused.
^^^^^^^^
assigned
Add a new api blk_mq_driver_tag_busy(), it will be called when get
driver tag failed, and move tag sharing from blk_mq_tag_busy() to
blk_mq_driver_tag_busy().
+ spin_lock_irq(&tags->lock);
+ WRITE_ONCE(tags->ctl.share_queues, tags->ctl.active_queues);
+ blk_mq_update_wake_batch(tags, tags->ctl.share_queues);
+ spin_unlock_irq(&tags->lock);
+}
Are all tags->ctl.share_queues changes protected by tags->lock? If so, please
use a regular assignment to update that member variable instead of using
WRITE_ONCE().
@@ -735,6 +736,7 @@ struct request *blk_mq_alloc_request_hctx(struct request_queue *q,
struct tag_sharing_ctl {
unsigned int active_queues;
+ unsigned int share_queues;
};
Please rename "share_queues" into "shared_queues" such that the names of
both struct members start with an adjective.
Thanks,
Bart.
