[RFC PATCH] blk-mq: hctx has only one ctx mapping is no need to redirect the completion

Christoph Hellwig hch at lst.de
Wed Sep 21 23:20:10 PDT 2022


On Wed, Sep 21, 2022 at 11:32:03AM +0800, Liu Song wrote:
> From: Liu Song <liusong at linux.alibaba.com>
> 
> High-performance NVMe devices usually support a large hw queue, which

a larger number of?

>  	/*
> -	 * For a polled request, always complete locally, it's pointless
> -	 * to redirect the completion.
> +	 * For request which hctx has only one ctx mapping,
> +	 * or a polled request, always complete locally,
> +	 * it's pointless to redirect the completion.
>  	 */
> -	if (rq->cmd_flags & REQ_POLLED)
> +	if (rq->mq_hctx->nr_ctx == 1 ||
> +		rq->cmd_flags & REQ_POLLED)

Some very odd comment formatting and and indentation here.



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