* [PATCH] scsi_debug: Use scsi-mq if it has been enabled
@ 2018-01-24 0:39 Bart Van Assche
2018-01-24 6:29 ` Douglas Gilbert
2018-01-26 7:58 ` Christoph Hellwig
0 siblings, 2 replies; 4+ messages in thread
From: Bart Van Assche @ 2018-01-24 0:39 UTC (permalink / raw)
To: Martin K . Petersen, James E . J . Bottomley
Cc: linux-scsi, Bart Van Assche, Douglas Gilbert, Hannes Reinecke,
Christoph Hellwig
Since we want to remove the single queue code from the SCSI core
at the appropriate time and since scsi-mq performs better than
scsi-sq even when using only a single hardware queue, use scsi-mq
if it has been enabled.
Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com>
Cc: Douglas Gilbert <dgilbert@interlog.com>
Cc: Hannes Reinecke <hare@suse.com>
Cc: Christoph Hellwig <hch@lst.de>
---
drivers/scsi/scsi_debug.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/scsi/scsi_debug.c b/drivers/scsi/scsi_debug.c
index a5986dae9020..40df3eea72c8 100644
--- a/drivers/scsi/scsi_debug.c
+++ b/drivers/scsi/scsi_debug.c
@@ -5782,7 +5782,7 @@ static int sdebug_driver_probe(struct device * dev)
}
/* Decide whether to tell scsi subsystem that we want mq */
/* Following should give the same answer for each host */
- sdebug_mq_active = shost_use_blk_mq(hpnt) && (submit_queues > 1);
+ sdebug_mq_active = shost_use_blk_mq(hpnt);
if (sdebug_mq_active)
hpnt->nr_hw_queues = submit_queues;
--
2.15.1
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH] scsi_debug: Use scsi-mq if it has been enabled
2018-01-24 0:39 [PATCH] scsi_debug: Use scsi-mq if it has been enabled Bart Van Assche
@ 2018-01-24 6:29 ` Douglas Gilbert
2018-01-26 7:58 ` Christoph Hellwig
1 sibling, 0 replies; 4+ messages in thread
From: Douglas Gilbert @ 2018-01-24 6:29 UTC (permalink / raw)
To: Bart Van Assche, Martin K . Petersen, James E . J . Bottomley
Cc: linux-scsi, Hannes Reinecke, Christoph Hellwig
On 2018-01-23 07:39 PM, Bart Van Assche wrote:
> Since we want to remove the single queue code from the SCSI core
> at the appropriate time and since scsi-mq performs better than
> scsi-sq even when using only a single hardware queue, use scsi-mq
> if it has been enabled.
>
> Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com>
> Cc: Douglas Gilbert <dgilbert@interlog.com>
> Cc: Hannes Reinecke <hare@suse.com>
> Cc: Christoph Hellwig <hch@lst.de>
Acked: Douglas Gilbert <dgilbert@interlog.com>
> ---
> drivers/scsi/scsi_debug.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/scsi/scsi_debug.c b/drivers/scsi/scsi_debug.c
> index a5986dae9020..40df3eea72c8 100644
> --- a/drivers/scsi/scsi_debug.c
> +++ b/drivers/scsi/scsi_debug.c
> @@ -5782,7 +5782,7 @@ static int sdebug_driver_probe(struct device * dev)
> }
> /* Decide whether to tell scsi subsystem that we want mq */
> /* Following should give the same answer for each host */
> - sdebug_mq_active = shost_use_blk_mq(hpnt) && (submit_queues > 1);
> + sdebug_mq_active = shost_use_blk_mq(hpnt);
> if (sdebug_mq_active)
> hpnt->nr_hw_queues = submit_queues;
>
>
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] scsi_debug: Use scsi-mq if it has been enabled
2018-01-24 0:39 [PATCH] scsi_debug: Use scsi-mq if it has been enabled Bart Van Assche
2018-01-24 6:29 ` Douglas Gilbert
@ 2018-01-26 7:58 ` Christoph Hellwig
2018-01-26 16:10 ` Bart Van Assche
1 sibling, 1 reply; 4+ messages in thread
From: Christoph Hellwig @ 2018-01-26 7:58 UTC (permalink / raw)
To: Bart Van Assche
Cc: Martin K . Petersen, James E . J . Bottomley, linux-scsi,
Douglas Gilbert, Hannes Reinecke, Christoph Hellwig
On Tue, Jan 23, 2018 at 04:39:58PM -0800, Bart Van Assche wrote:
> Since we want to remove the single queue code from the SCSI core
> at the appropriate time and since scsi-mq performs better than
> scsi-sq even when using only a single hardware queue, use scsi-mq
> if it has been enabled.
scsi_debug already always uses scsi-mq if enabled. The somewhat
misnamed sdebug_mq_active variable is only used for decoding
multiqueue tags. That being said the blk_mq_unique_tag* helpers
should be safe to use even without blk-mq, so the variable could
probably just be removed entirely.
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] scsi_debug: Use scsi-mq if it has been enabled
2018-01-26 7:58 ` Christoph Hellwig
@ 2018-01-26 16:10 ` Bart Van Assche
0 siblings, 0 replies; 4+ messages in thread
From: Bart Van Assche @ 2018-01-26 16:10 UTC (permalink / raw)
To: hch@lst.de
Cc: jejb@linux.vnet.ibm.com, linux-scsi@vger.kernel.org,
dgilbert@interlog.com, hare@suse.com, martin.petersen@oracle.com
On Fri, 2018-01-26 at 08:58 +0100, Christoph Hellwig wrote:
> scsi_debug already always uses scsi-mq if enabled. The somewhat
> misnamed sdebug_mq_active variable is only used for decoding
> multiqueue tags. That being said the blk_mq_unique_tag* helpers
> should be safe to use even without blk-mq, so the variable could
> probably just be removed entirely.
Hello Christoph,
Removing sdebug_mq_active sounds like a good idea to me. I will rework this
patch.
Bart.
^ permalink raw reply [flat|nested] 4+ messages in thread
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2018-01-24 0:39 [PATCH] scsi_debug: Use scsi-mq if it has been enabled Bart Van Assche
2018-01-24 6:29 ` Douglas Gilbert
2018-01-26 7:58 ` Christoph Hellwig
2018-01-26 16:10 ` Bart Van Assche
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