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From: Jens Axboe <axboe@kernel.dk>
To: Fengnan Chang <fengnanchang@gmail.com>,
	asml.silence@gmail.com, io-uring@vger.kernel.org
Cc: Fengnan Chang <changfengnan@bytedance.com>,
	Diangang Li <lidiangang@bytedance.com>
Subject: Re: [RFC PATCH 1/2] blk-mq: delete task running check in blk_hctx_poll
Date: Wed, 10 Dec 2025 02:53:31 -0700	[thread overview]
Message-ID: <0278628f-5576-434f-ac67-476adabca29a@kernel.dk> (raw)
In-Reply-To: <20251210085501.84261-2-changfengnan@bytedance.com>

On 12/10/25 1:55 AM, Fengnan Chang wrote:
> In blk_hctx_poll, it always check task is running or not, and return 1
> if task is running, it's not reasonable for current caller, especially
> io_uring, which is always running and cause BLK_POLL_ONESHOT is set.
> 
> It looks like there has been this judgment for historical reasons, and
> in very early versions of this function the user would set the process
> state to TASK_UNINTERRUPTIBLE.
> 
> Signed-off-by: Diangang Li <lidiangang@bytedance.com>
> Signed-off-by: Fengnan Chang <changfengnan@bytedance.com>
> ---
>  block/blk-mq.c | 2 --
>  1 file changed, 2 deletions(-)
> 
> diff --git a/block/blk-mq.c b/block/blk-mq.c
> index 0b8b72194003..b0eb90c50afb 100644
> --- a/block/blk-mq.c
> +++ b/block/blk-mq.c
> @@ -5172,8 +5172,6 @@ static int blk_hctx_poll(struct request_queue *q, struct blk_mq_hw_ctx *hctx,
>  
>  		if (signal_pending_state(state, current))
>  			__set_current_state(TASK_RUNNING);
> -		if (task_is_running(current))
> -			return 1;
>  
>  		if (ret < 0 || (flags & BLK_POLL_ONESHOT))
>  			break;

Applied with the other task-is-running remnants killed, too.

-- 
Jens Axboe


  parent reply	other threads:[~2025-12-10  9:53 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-12-10  8:54 [RFC PATCH 0/2] io_uring: fix io may accumulation in poll mode Fengnan Chang
2025-12-10  8:55 ` [RFC PATCH 1/2] blk-mq: delete task running check in blk_hctx_poll Fengnan Chang
2025-12-10  9:19   ` Jens Axboe
2025-12-10  9:53   ` Jens Axboe [this message]
2025-12-10  8:55 ` [RFC PATCH 2/2] io_uring: fix io may accumulation in poll mode Fengnan Chang
2025-12-11  2:15   ` Jens Axboe
2025-12-11  4:10     ` Jens Axboe
2025-12-11  7:38       ` Fengnan
2025-12-11 10:22         ` Jens Axboe
2025-12-11 10:33           ` Jens Axboe
2025-12-11 11:13             ` Fengnan Chang
2025-12-11 11:19               ` Jens Axboe
2025-12-12  1:41             ` Fengnan Chang
2025-12-12  1:53               ` Jens Axboe
2025-12-12  2:12                 ` Fengnan Chang
2025-12-12  5:11                   ` Jens Axboe
2025-12-12  8:58                     ` Jens Axboe
2025-12-12  9:49                       ` Fengnan Chang
2025-12-12 20:22                         ` Jens Axboe
2025-12-12 13:32                     ` Diangang Li
2025-12-12 20:09                       ` Jens Axboe
2025-12-10  9:53 ` (subset) [RFC PATCH 0/2] " Jens Axboe

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