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From: Bart Van Assche <bvanassche@acm.org>
To: Sreekanth Reddy <sreekanth.reddy@broadcom.com>,
	linux-scsi@vger.kernel.org, martin.petersen@oracle.com
Subject: Re: [PATCH] mpt3sas: Add io_uring iopoll support
Date: Sun, 29 Aug 2021 19:40:00 -0700	[thread overview]
Message-ID: <3efd607c-43df-4c2a-7948-de794b414406@acm.org> (raw)
In-Reply-To: <20210727081212.2742-1-sreekanth.reddy@broadcom.com>

On 7/27/21 01:12, Sreekanth Reddy wrote:
> +	/*
> +	 * wait for current poll to complete.
> +	 */
> +	for (qid = 0; qid < iopoll_q_count; qid++) {
> +		while (atomic_read(&ioc->io_uring_poll_queues[qid].busy))
> +			udelay(500);
> +	}

So this loop busy-waits without calling cpu_relax()? That's not OK ...

An additional question: is mpt3sas_base_hard_reset_handler() the only 
function that calls mpt3sas_base_pause_mq_polling() and 
mpt3sas_base_resume_mq_polling()? If so, why have these functions been 
introduced since the SCSI core guarantees that all pending requests 
either have failed or have timed out before the SCSI error handler is 
invoked?

Thanks,

Bart.

  parent reply	other threads:[~2021-08-30  2:40 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-27  8:12 [PATCH] mpt3sas: Add io_uring iopoll support Sreekanth Reddy
2021-08-10  3:11 ` Martin K. Petersen
2021-08-17  3:20 ` Martin K. Petersen
2021-08-30  2:40 ` Bart Van Assche [this message]
2021-08-30 17:15   ` Sreekanth Reddy

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