From: Max Gurtovoy <mgurtovoy@nvidia.com>
To: "Michael S. Tsirkin" <mst@redhat.com>, <linux-kernel@vger.kernel.org>
Cc: Jason Wang <jasowang@redhat.com>,
Paolo Bonzini <pbonzini@redhat.com>,
Stefan Hajnoczi <stefanha@redhat.com>,
Jens Axboe <axboe@kernel.dk>,
<virtualization@lists.linux-foundation.org>,
<linux-block@vger.kernel.org>
Subject: Re: [PATCH] virtio_blk: allow 0 as num_request_queues
Date: Sun, 24 Oct 2021 17:19:33 +0300 [thread overview]
Message-ID: <855eb993-074b-24b9-a184-d479bd0b342b@nvidia.com> (raw)
In-Reply-To: <20211024135412.1516393-1-mst@redhat.com>
On 10/24/2021 4:54 PM, Michael S. Tsirkin wrote:
> The default value is 0 meaning "no limit". However if 0
> is specified on the command line it is instead silently
> converted to 1. Further, the value is already validated
> at point of use, there's no point in duplicating code
> validating the value when it is set.
>
> Simplify the code while making the behaviour more consistent
> by using plain module_param.
>
> Fixes: 1a662cf6cb9a ("virtio-blk: add num_request_queues module parameter")
> Cc: Max Gurtovoy <mgurtovoy@nvidia.com>
> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
> ---
> drivers/block/virtio_blk.c | 14 +-------------
> 1 file changed, 1 insertion(+), 13 deletions(-)
>
> diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c
> index 6318134aab76..c336d9bb9105 100644
> --- a/drivers/block/virtio_blk.c
> +++ b/drivers/block/virtio_blk.c
> @@ -30,20 +30,8 @@
> #define VIRTIO_BLK_INLINE_SG_CNT 2
> #endif
>
> -static int virtblk_queue_count_set(const char *val,
> - const struct kernel_param *kp)
> -{
> - return param_set_uint_minmax(val, kp, 1, nr_cpu_ids);
> -}
> -
> -static const struct kernel_param_ops queue_count_ops = {
> - .set = virtblk_queue_count_set,
> - .get = param_get_uint,
> -};
> -
> static unsigned int num_request_queues;
> -module_param_cb(num_request_queues, &queue_count_ops, &num_request_queues,
> - 0644);
> +module_param(num_request_queues, uint, 0644);
Not the best solution.
You can set the param to 1024 but in practice nr_cpu_ids can be 32 for
example.
> MODULE_PARM_DESC(num_request_queues,
> "Limit the number of request queues to use for blk device. "
> "0 for no limit. "
next prev parent reply other threads:[~2021-10-24 14:19 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-24 13:54 [PATCH] virtio_blk: allow 0 as num_request_queues Michael S. Tsirkin
2021-10-24 14:19 ` Max Gurtovoy [this message]
2021-10-24 15:11 ` Michael S. Tsirkin
2021-10-24 15:29 ` Max Gurtovoy
2021-10-24 15:49 ` Michael S. Tsirkin
2021-10-24 22:30 ` Max Gurtovoy
2021-10-25 21:09 ` Michael S. Tsirkin
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