Re: [PATCH 1/1] block: Use RCU in blk_mq_[un]quiesce_tagset() instead of set->tag_list_lock

From: Bart Van Assche

Date: Thu Dec 04 2025 - 14:07:06 EST


On 12/4/25 8:42 AM, Mohamed Khalfella wrote:
Is blk_mq_del_queue_tag_set() performance sensitive such that it can not
take synchronize_rcu()? It is not in IO codepath, right?

Introducing a new synchronize_rcu() call almost always slows down some workload so it should be avoided if possible.

> I can not think of an easy way to do that. Suggestions are welcomed.

I can't find the implementation of nvme_dev_disable_locked(). What
kernel tree does your patch apply to?

$ git grep -w nvme_dev_disable_locked axboe-block/for-next | wc -l
0

Thanks,

Bart.