Re: [PATCH 2/2] blk-mq: ensure a q_usage_counter reference is held when splitting bios

Christoph Hellwig
2024-01-12T14:25:13Z

On Fri, Jan 12, 2024 at 07:22:18AM -0700, Jens Axboe wrote:
> Yep it is pretty cheap, but it's not free. Here's a test where we just
> grab a ref and drop it, which should arguably be cheaper than doing a
> ref at the top and dropping it at the bottom due to temporal locality:
>
> 5.01% +0.86% [kernel.vmlinux] [k] blk_mq_submit_bio

Ok. Do you want to send out your version formally?