[PATCH v9 net-next 1/2] hv_sock: introduce Hyper-V Sockets

[David Miller]

From: Dexuan Cui <decui at microsoft.com>
Date: Wed,  4 May 2016 09:56:57 -0700

> +#define VMBUS_RINGBUFFER_SIZE_HVSOCK_RECV (5 * PAGE_SIZE)
> +#define VMBUS_RINGBUFFER_SIZE_HVSOCK_SEND (5 * PAGE_SIZE)
> +
> +#define HVSOCK_RCV_BUF_SZ	VMBUS_RINGBUFFER_SIZE_HVSOCK_RECV
 ...
> +struct hvsock_sock {
 ...
> +	/* The 'hdr' and 'buf' in the below 'send' and 'recv' definitions must
> +	 * be consecutive: see hvsock_send_data() and hvsock_recv_data().
> +	 */
> +	struct {
> +		struct vmpipe_proto_header hdr;
> +		u8 buf[HVSOCK_SND_BUF_SZ];
> +	} send;
> +
> +	struct {
> +		struct vmpipe_proto_header hdr;
> +		u8 buf[HVSOCK_RCV_BUF_SZ];
> +
> +		unsigned int data_len;
> +		unsigned int data_offset;
> +	} recv;

I don't think allocating 5 pages of unswappable memory for every Hyper-V socket
created is reasonable.