From: Bart Van Assche <Bart.VanAssche@sandisk.com>
To: "osandov@osandov.com" <osandov@osandov.com>,
"kashyap.desai@broadcom.com" <kashyap.desai@broadcom.com>,
"axboe@kernel.dk" <axboe@kernel.dk>
Cc: "linux-scsi@vger.kernel.org" <linux-scsi@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"hch@infradead.org" <hch@infradead.org>,
"linux-block@vger.kernel.org" <linux-block@vger.kernel.org>,
"paolo.valente@linaro.org" <paolo.valente@linaro.org>
Subject: Re: Device or HBA level QD throttling creates randomness in sequetial workload
Date: Mon, 30 Jan 2017 16:30:59 +0000 [thread overview]
Message-ID: <1485793840.2712.1.camel@sandisk.com> (raw)
In-Reply-To: <e1e827ba633f780b00d070e087204d5c@mail.gmail.com>
On Mon, 2017-01-30 at 19:22 +0530, Kashyap Desai wrote:
> - if (atomic_inc_return(&instance->fw_outstanding) >
> - instance->host->can_queue) {
> - atomic_dec(&instance->fw_outstanding);
> - return SCSI_MLQUEUE_HOST_BUSY;
> - }
> + if (atomic_inc_return(&instance->fw_outstanding) > safe_can_queue) {
> + is_nonrot = blk_queue_nonrot(scmd->device->request_queue);
> + /* For rotational device wait for sometime to get fusion command
> from pool.
> + * This is just to reduce proactive re-queue at mid layer which is
> not
> + * sending sorted IO in SCSI.MQ mode.
> + */
> + if (!is_nonrot)
> + udelay(100);
> + }
The SCSI core does not allow to sleep inside the queuecommand() callback
function.
Bart.
next prev parent reply other threads:[~2017-01-30 16:31 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-10-24 18:54 Device or HBA level QD throttling creates randomness in sequetial workload Kashyap Desai
2016-10-26 20:56 ` Omar Sandoval
2016-10-31 17:24 ` Jens Axboe
2016-11-01 5:40 ` Kashyap Desai
2017-01-30 13:52 ` Kashyap Desai
2017-01-30 16:30 ` Bart Van Assche [this message]
2017-01-30 16:32 ` Jens Axboe
2017-01-30 18:28 ` Kashyap Desai
2017-01-30 18:29 ` Jens Axboe
-- strict thread matches above, loose matches on Subject: below --
2016-10-21 12:13 Kashyap Desai
2016-10-21 21:31 ` Omar Sandoval
2016-10-24 13:05 ` Kashyap Desai
2016-10-24 15:41 ` Omar Sandoval
2016-10-20 10:08 Kashyap Desai
2016-10-20 9:58 Kashyap Desai
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