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

[Dexuan Cui]

> From: David Miller [mailto:davem@xxxxxxxxxxxxx]
> Sent: Saturday, May 7, 2016 1:04
> To: Dexuan Cui <decui@xxxxxxxxxxxxx>
> Cc: gregkh@xxxxxxxxxxxxxxxxxxx; netdev@xxxxxxxxxxxxxxx; linux-
> kernel@xxxxxxxxxxxxxxx; devel@xxxxxxxxxxxxxxxxxxxxxx; olaf@xxxxxxxxx;
> apw@xxxxxxxxxxxxx; jasowang@xxxxxxxxxx; cavery@xxxxxxxxxx; KY
> Srinivasan <kys@xxxxxxxxxxxxx>; Haiyang Zhang <haiyangz@xxxxxxxxxxxxx>;
> joe@xxxxxxxxxxx; vkuznets@xxxxxxxxxx
> Subject: Re: [PATCH v9 net-next 1/2] hv_sock: introduce Hyper-V Sockets
> 
> From: Dexuan Cui <decui@xxxxxxxxxxxxx>
> 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.

Thanks for the comment, David!

I should be able to make 'send', 'recv' here to pointers and use vmalloc()
to allocate the memory for them.  I will do this.

Thanks,
-- Dexuan