From: Max Gurtovoy <mgurtovoy@nvidia.com>
To: Leon Romanovsky <leon@kernel.org>
Cc: Chaitanya Kulkarni <ckulkarnilinux@gmail.com>,
<hch@infradead.org>, <mst@redhat.com>,
<virtualization@lists.linux-foundation.org>,
<kvm@vger.kernel.org>, <stefanha@redhat.com>,
<israelr@nvidia.com>, <nitzanc@nvidia.com>, <oren@nvidia.com>,
<linux-block@vger.kernel.org>, <axboe@kernel.dk>
Subject: Re: [PATCH v3 1/1] virtio-blk: add num_request_queues module parameter
Date: Sun, 5 Sep 2021 14:16:58 +0300 [thread overview]
Message-ID: <5aada544-356f-5363-c6e4-6885e9812f82@nvidia.com> (raw)
In-Reply-To: <YTSZpm1GZGT4BUDR@unreal>
On 9/5/2021 1:19 PM, Leon Romanovsky wrote:
> On Sun, Sep 05, 2021 at 12:19:09PM +0300, Max Gurtovoy wrote:
>> On 9/5/2021 11:49 AM, Chaitanya Kulkarni wrote:
>>> On 9/5/2021 12:46 AM, Leon Romanovsky wrote:
>>>>> +static unsigned int num_request_queues;
>>>>> +module_param_cb(num_request_queues, &queue_count_ops,
>>>>> &num_request_queues,
>>>>> + 0644);
>>>>> +MODULE_PARM_DESC(num_request_queues,
>>>>> + "Number of request queues to use for blk device.
>>>>> Should > 0");
>>>>> +
>>>> Won't it limit all virtio block devices to the same limit?
>>>>
>>>> It is very common to see multiple virtio-blk devices on the same system
>>>> and they probably need different limits.
>>>>
>>>> Thanks
>>>
>>> Without looking into the code, that can be done adding a configfs
>>>
>>> interface and overriding a global value (module param) when it is set
>>> from
>>>
>>> configfs.
>>>
>>>
>> You have many ways to overcome this issue.
>>
>> For example:
>>
>> # ls -l /sys/block/vda/mq/
>> drwxr-xr-x 18 root root 0 Sep 5 12:14 0
>> drwxr-xr-x 18 root root 0 Sep 5 12:14 1
>> drwxr-xr-x 18 root root 0 Sep 5 12:14 2
>> drwxr-xr-x 18 root root 0 Sep 5 12:14 3
>>
>> # echo virtio0 > /sys/bus/virtio/drivers/virtio_blk/unbind
>>
>> # echo 8 > /sys/module/virtio_blk/parameters/num_request_queues
> This is global to all virtio-blk devices.
You define a global module param but you bind/unbind a specific device.
Do you have a better way to control it ?
if the device is already probed, it's too late to change the queue_num.
>
>> # echo virtio0 > /sys/bus/virtio/drivers/virtio_blk/bind
>>
>> # ls -l /sys/block/vda/mq/
>> drwxr-xr-x 10 root root 0 Sep 5 12:17 0
>> drwxr-xr-x 10 root root 0 Sep 5 12:17 1
>> drwxr-xr-x 10 root root 0 Sep 5 12:17 2
>> drwxr-xr-x 10 root root 0 Sep 5 12:17 3
>> drwxr-xr-x 10 root root 0 Sep 5 12:17 4
>> drwxr-xr-x 10 root root 0 Sep 5 12:17 5
>> drwxr-xr-x 10 root root 0 Sep 5 12:17 6
>> drwxr-xr-x 10 root root 0 Sep 5 12:17 7
>>
>> -Max.
>>
>>
next prev parent reply other threads:[~2021-09-05 11:17 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-02 20:46 [PATCH v3 1/1] virtio-blk: add num_request_queues module parameter Max Gurtovoy
2021-09-03 6:06 ` Pankaj Gupta
2021-09-05 7:46 ` Leon Romanovsky
2021-09-05 8:49 ` Chaitanya Kulkarni
2021-09-05 9:19 ` Max Gurtovoy
2021-09-05 10:19 ` Leon Romanovsky
2021-09-05 11:16 ` Max Gurtovoy [this message]
2021-09-05 13:10 ` Leon Romanovsky
2021-09-05 13:16 ` Max Gurtovoy
2021-09-05 10:20 ` Leon Romanovsky
2021-09-05 15:15 ` Michael S. Tsirkin
2021-09-07 23:04 ` Leon Romanovsky
2021-10-22 9:30 ` Michael S. Tsirkin
2021-10-24 7:19 ` Max Gurtovoy
2021-10-24 8:12 ` Max Gurtovoy
2021-10-24 8:48 ` Michael S. Tsirkin
2021-10-24 10:57 ` Max Gurtovoy
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