From: John Garry <john.garry@huawei.com>
To: Ming Lei <ming.lei@redhat.com>
Cc: <jejb@linux.vnet.ibm.com>, <martin.petersen@oracle.com>,
<linux-scsi@vger.kernel.org>, <linuxarm@huawei.com>,
<linux-kernel@vger.kernel.org>, <hare@suse.com>
Subject: Re: [PATCH 6/6] scsi: hisi_sas: Expose multiple hw queues for v3 as experimental
Date: Mon, 11 Nov 2019 14:02:27 +0000 [thread overview]
Message-ID: <bd3b09f7-4a51-7cec-49c4-8e2eab3bdfd0@huawei.com> (raw)
In-Reply-To: <20191027081910.GB16704@ming.t460p>
On 27/10/2019 08:19, Ming Lei wrote:
>> .this_id = -1,
>> @@ -3265,8 +3300,14 @@ hisi_sas_v3_probe(struct pci_dev *pdev, const struct pci_device_id *id)
>> shost->max_lun = ~0;
>> shost->max_channel = 1;
>> shost->max_cmd_len = 16;
>> - shost->can_queue = HISI_SAS_UNRESERVED_IPTT;
>> - shost->cmd_per_lun = HISI_SAS_UNRESERVED_IPTT;
>> +
Hi Ming,
I mentioned in the thread "blk-mq: improvement on handling IO during CPU
hotplug" that I was using this series to test that patchset.
So just with this patchset (and without yours), I get what looks like
some IO errors in the LLDD. The error is an underflow error. I can't
figure out what is the cause.
I'm wondering if the SCSI command is getting corrupted someway.
>> + if (expose_mq_experimental) {
>> + shost->can_queue = HISI_SAS_MAX_COMMANDS;
>> + shost->cmd_per_lun = HISI_SAS_MAX_COMMANDS;
> The above is contradictory with current 'nr_hw_queues''s meaning,
> see commit on Scsi_Host.nr_hw_queues.
>
Right, so I am generating the hostwide tag in the LLDD. And the Scsi
host-wide host_busy counter should ensure that we don't pump too much IO
to the HBA.
What other problem will this cause?
Thanks,
John
>
> /*
> * In scsi-mq mode, the number of hardware queues supported by the LLD.
> *
> * Note: it is assumed that each hardware queue has a queue depth of
> * can_queue. In other words, the total queue depth per host
> * is nr_hw_queues * can_queue.
> */
>
> Also this implementation wastes memory too much.
>
>
> thanks,
> Ming
next prev parent reply other threads:[~2019-11-11 14:02 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-24 14:21 [PATCH 0/6] hisi_sas: Expose multiple hw queues for v3 hw as experimental John Garry
2019-10-24 14:21 ` [PATCH 1/6] scsi: hisi_sas: Use sbitmap for IPTT management John Garry
2019-10-24 14:21 ` [PATCH 2/6] scsi: hisi_sas: Pass scsi_cmnd pointer to hisi_sas_hw.slot_index_alloc John Garry
2019-10-24 14:21 ` [PATCH 3/6] scsi: hisi_sas: Add bitmaps_alloc_v3_hw() John Garry
2019-10-24 14:21 ` [PATCH 4/6] scsi: hisi_sas: Add slot_index_alloc_v3_hw() and slot_index_free_v3_hw() John Garry
2019-10-24 14:21 ` [PATCH 5/6] scsi: hisi_sas: Split interrupt_init_v3_hw() John Garry
2019-10-24 14:21 ` [PATCH 6/6] scsi: hisi_sas: Expose multiple hw queues for v3 as experimental John Garry
2019-10-27 8:19 ` Ming Lei
2019-11-11 14:02 ` John Garry [this message]
2019-11-12 11:10 ` Ming Lei
2019-11-12 13:54 ` John Garry
2019-11-12 14:35 ` John Garry
2019-10-25 16:04 ` [PATCH 0/6] hisi_sas: Expose multiple hw queues for v3 hw " John Garry
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