diff mbox series

[v2,8/8] vsock/virtio: make the RX buffer size tunable

Message ID 20190510125843.95587-9-sgarzare@redhat.com
State Changes Requested
Delegated to: David Miller
Headers show
Series [v2,1/8] vsock/virtio: limit the memory used per-socket | expand

Commit Message

Stefano Garzarella May 10, 2019, 12:58 p.m. UTC
The RX buffer size determines the memory consumption of the
vsock/virtio guest driver, so we make it tunable through
a module parameter.

The size allowed are between 4 KB and 64 KB in order to be
compatible with old host drivers.

Suggested-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
---
 include/linux/virtio_vsock.h     |  1 +
 net/vmw_vsock/virtio_transport.c | 27 ++++++++++++++++++++++++++-
 2 files changed, 27 insertions(+), 1 deletion(-)

Comments

Jason Wang May 13, 2019, 10:05 a.m. UTC | #1
On 2019/5/10 下午8:58, Stefano Garzarella wrote:
> The RX buffer size determines the memory consumption of the
> vsock/virtio guest driver, so we make it tunable through
> a module parameter.
>
> The size allowed are between 4 KB and 64 KB in order to be
> compatible with old host drivers.
>
> Suggested-by: Stefan Hajnoczi <stefanha@redhat.com>
> Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>


I don't see much value of doing this through kernel command line. We 
should deal with them automatically like what virtio-net did. Or even a 
module parameter is better.

Thanks


> ---
>   include/linux/virtio_vsock.h     |  1 +
>   net/vmw_vsock/virtio_transport.c | 27 ++++++++++++++++++++++++++-
>   2 files changed, 27 insertions(+), 1 deletion(-)
>
> diff --git a/include/linux/virtio_vsock.h b/include/linux/virtio_vsock.h
> index 5a9d25be72df..b9f8c3d91f80 100644
> --- a/include/linux/virtio_vsock.h
> +++ b/include/linux/virtio_vsock.h
> @@ -13,6 +13,7 @@
>   #define VIRTIO_VSOCK_DEFAULT_RX_BUF_SIZE	(1024 * 64)
>   #define VIRTIO_VSOCK_MAX_BUF_SIZE		0xFFFFFFFFUL
>   #define VIRTIO_VSOCK_MAX_PKT_BUF_SIZE		(1024 * 64)
> +#define VIRTIO_VSOCK_MIN_PKT_BUF_SIZE		(1024 * 4)
>   
>   enum {
>   	VSOCK_VQ_RX     = 0, /* for host to guest data */
> diff --git a/net/vmw_vsock/virtio_transport.c b/net/vmw_vsock/virtio_transport.c
> index af1d2ce12f54..732398b4e28f 100644
> --- a/net/vmw_vsock/virtio_transport.c
> +++ b/net/vmw_vsock/virtio_transport.c
> @@ -66,6 +66,31 @@ struct virtio_vsock {
>   	u32 guest_cid;
>   };
>   
> +static unsigned int rx_buf_size = VIRTIO_VSOCK_DEFAULT_RX_BUF_SIZE;
> +
> +static int param_set_rx_buf_size(const char *val, const struct kernel_param *kp)
> +{
> +	unsigned int size;
> +	int ret;
> +
> +	ret = kstrtouint(val, 0, &size);
> +	if (ret)
> +		return ret;
> +
> +	if (size < VIRTIO_VSOCK_MIN_PKT_BUF_SIZE ||
> +	    size > VIRTIO_VSOCK_MAX_PKT_BUF_SIZE)
> +		return -EINVAL;
> +
> +	return param_set_uint(val, kp);
> +};
> +
> +static const struct kernel_param_ops param_ops_rx_buf_size = {
> +	.set = param_set_rx_buf_size,
> +	.get = param_get_uint,
> +};
> +
> +module_param_cb(rx_buf_size, &param_ops_rx_buf_size, &rx_buf_size, 0644);
> +
>   static struct virtio_vsock *virtio_vsock_get(void)
>   {
>   	return the_virtio_vsock;
> @@ -261,7 +286,7 @@ virtio_transport_cancel_pkt(struct vsock_sock *vsk)
>   
>   static void virtio_vsock_rx_fill(struct virtio_vsock *vsock)
>   {
> -	int buf_len = VIRTIO_VSOCK_DEFAULT_RX_BUF_SIZE;
> +	int buf_len = rx_buf_size;
>   	struct virtio_vsock_pkt *pkt;
>   	struct scatterlist hdr, buf, *sgs[2];
>   	struct virtqueue *vq;
Jason Wang May 13, 2019, 12:46 p.m. UTC | #2
On 2019/5/13 下午6:05, Jason Wang wrote:
>
> On 2019/5/10 下午8:58, Stefano Garzarella wrote:
>> The RX buffer size determines the memory consumption of the
>> vsock/virtio guest driver, so we make it tunable through
>> a module parameter.
>>
>> The size allowed are between 4 KB and 64 KB in order to be
>> compatible with old host drivers.
>>
>> Suggested-by: Stefan Hajnoczi <stefanha@redhat.com>
>> Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
>
>
> I don't see much value of doing this through kernel command line. We 
> should deal with them automatically like what virtio-net did. Or even 
> a module parameter is better.
>
> Thanks


Sorry, I misread the patch. But even module parameter is something not 
flexible enough. We should deal with them transparently.

Thanks


>
>
>> ---
>>   include/linux/virtio_vsock.h     |  1 +
>>   net/vmw_vsock/virtio_transport.c | 27 ++++++++++++++++++++++++++-
>>   2 files changed, 27 insertions(+), 1 deletion(-)
>>
>> diff --git a/include/linux/virtio_vsock.h b/include/linux/virtio_vsock.h
>> index 5a9d25be72df..b9f8c3d91f80 100644
>> --- a/include/linux/virtio_vsock.h
>> +++ b/include/linux/virtio_vsock.h
>> @@ -13,6 +13,7 @@
>>   #define VIRTIO_VSOCK_DEFAULT_RX_BUF_SIZE    (1024 * 64)
>>   #define VIRTIO_VSOCK_MAX_BUF_SIZE        0xFFFFFFFFUL
>>   #define VIRTIO_VSOCK_MAX_PKT_BUF_SIZE        (1024 * 64)
>> +#define VIRTIO_VSOCK_MIN_PKT_BUF_SIZE        (1024 * 4)
>>     enum {
>>       VSOCK_VQ_RX     = 0, /* for host to guest data */
>> diff --git a/net/vmw_vsock/virtio_transport.c 
>> b/net/vmw_vsock/virtio_transport.c
>> index af1d2ce12f54..732398b4e28f 100644
>> --- a/net/vmw_vsock/virtio_transport.c
>> +++ b/net/vmw_vsock/virtio_transport.c
>> @@ -66,6 +66,31 @@ struct virtio_vsock {
>>       u32 guest_cid;
>>   };
>>   +static unsigned int rx_buf_size = VIRTIO_VSOCK_DEFAULT_RX_BUF_SIZE;
>> +
>> +static int param_set_rx_buf_size(const char *val, const struct 
>> kernel_param *kp)
>> +{
>> +    unsigned int size;
>> +    int ret;
>> +
>> +    ret = kstrtouint(val, 0, &size);
>> +    if (ret)
>> +        return ret;
>> +
>> +    if (size < VIRTIO_VSOCK_MIN_PKT_BUF_SIZE ||
>> +        size > VIRTIO_VSOCK_MAX_PKT_BUF_SIZE)
>> +        return -EINVAL;
>> +
>> +    return param_set_uint(val, kp);
>> +};
>> +
>> +static const struct kernel_param_ops param_ops_rx_buf_size = {
>> +    .set = param_set_rx_buf_size,
>> +    .get = param_get_uint,
>> +};
>> +
>> +module_param_cb(rx_buf_size, &param_ops_rx_buf_size, &rx_buf_size, 
>> 0644);
>> +
>>   static struct virtio_vsock *virtio_vsock_get(void)
>>   {
>>       return the_virtio_vsock;
>> @@ -261,7 +286,7 @@ virtio_transport_cancel_pkt(struct vsock_sock *vsk)
>>     static void virtio_vsock_rx_fill(struct virtio_vsock *vsock)
>>   {
>> -    int buf_len = VIRTIO_VSOCK_DEFAULT_RX_BUF_SIZE;
>> +    int buf_len = rx_buf_size;
>>       struct virtio_vsock_pkt *pkt;
>>       struct scatterlist hdr, buf, *sgs[2];
>>       struct virtqueue *vq;
Stefano Garzarella May 14, 2019, 4:10 p.m. UTC | #3
On Mon, May 13, 2019 at 08:46:19PM +0800, Jason Wang wrote:
> 
> On 2019/5/13 下午6:05, Jason Wang wrote:
> > 
> > On 2019/5/10 下午8:58, Stefano Garzarella wrote:
> > > The RX buffer size determines the memory consumption of the
> > > vsock/virtio guest driver, so we make it tunable through
> > > a module parameter.
> > > 
> > > The size allowed are between 4 KB and 64 KB in order to be
> > > compatible with old host drivers.
> > > 
> > > Suggested-by: Stefan Hajnoczi <stefanha@redhat.com>
> > > Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
> > 
> > 
> > I don't see much value of doing this through kernel command line. We
> > should deal with them automatically like what virtio-net did. Or even a
> > module parameter is better.
> > 
> > Thanks
> 
> 
> Sorry, I misread the patch. But even module parameter is something not
> flexible enough. We should deal with them transparently.
> 

Okay, I'll try to understand how we can automatically adapt the RX
buffer size. Since the flow is stream based, the receiver doesn't know the
original packet size.

Maybe I can reuse the EWMA approach to understand if the buffers are
entirely filled or not.
In that case I can increase (e.g. double) or decrease the size.

I'll try to do it!

Thanks,
Stefano
diff mbox series

Patch

diff --git a/include/linux/virtio_vsock.h b/include/linux/virtio_vsock.h
index 5a9d25be72df..b9f8c3d91f80 100644
--- a/include/linux/virtio_vsock.h
+++ b/include/linux/virtio_vsock.h
@@ -13,6 +13,7 @@ 
 #define VIRTIO_VSOCK_DEFAULT_RX_BUF_SIZE	(1024 * 64)
 #define VIRTIO_VSOCK_MAX_BUF_SIZE		0xFFFFFFFFUL
 #define VIRTIO_VSOCK_MAX_PKT_BUF_SIZE		(1024 * 64)
+#define VIRTIO_VSOCK_MIN_PKT_BUF_SIZE		(1024 * 4)
 
 enum {
 	VSOCK_VQ_RX     = 0, /* for host to guest data */
diff --git a/net/vmw_vsock/virtio_transport.c b/net/vmw_vsock/virtio_transport.c
index af1d2ce12f54..732398b4e28f 100644
--- a/net/vmw_vsock/virtio_transport.c
+++ b/net/vmw_vsock/virtio_transport.c
@@ -66,6 +66,31 @@  struct virtio_vsock {
 	u32 guest_cid;
 };
 
+static unsigned int rx_buf_size = VIRTIO_VSOCK_DEFAULT_RX_BUF_SIZE;
+
+static int param_set_rx_buf_size(const char *val, const struct kernel_param *kp)
+{
+	unsigned int size;
+	int ret;
+
+	ret = kstrtouint(val, 0, &size);
+	if (ret)
+		return ret;
+
+	if (size < VIRTIO_VSOCK_MIN_PKT_BUF_SIZE ||
+	    size > VIRTIO_VSOCK_MAX_PKT_BUF_SIZE)
+		return -EINVAL;
+
+	return param_set_uint(val, kp);
+};
+
+static const struct kernel_param_ops param_ops_rx_buf_size = {
+	.set = param_set_rx_buf_size,
+	.get = param_get_uint,
+};
+
+module_param_cb(rx_buf_size, &param_ops_rx_buf_size, &rx_buf_size, 0644);
+
 static struct virtio_vsock *virtio_vsock_get(void)
 {
 	return the_virtio_vsock;
@@ -261,7 +286,7 @@  virtio_transport_cancel_pkt(struct vsock_sock *vsk)
 
 static void virtio_vsock_rx_fill(struct virtio_vsock *vsock)
 {
-	int buf_len = VIRTIO_VSOCK_DEFAULT_RX_BUF_SIZE;
+	int buf_len = rx_buf_size;
 	struct virtio_vsock_pkt *pkt;
 	struct scatterlist hdr, buf, *sgs[2];
 	struct virtqueue *vq;