On Mon, Sep 02, 2019 at 09:39:12AM +0100, Stefan Hajnoczi wrote: > On Sun, Sep 01, 2019 at 02:56:44AM -0400, Michael S. Tsirkin wrote: > > > > OK let me try to clarify. The idea is this: > > > > Let's say we queue a buffer of 4K, and we copy if len < 128 bytes. This > > means that in the worst case (128 byte packets), each byte of credit in > > the socket uses up 4K/128 = 16 bytes of kernel memory. In fact we need > > to also account for the virtio_vsock_pkt since I think it's kept around > > until userspace consumes it. > > > > Thus given X buf alloc allowed in the socket, we should publish X/16 > > credits to the other side. This will ensure the other side does not send > > more than X/16 bytes for a given socket and thus we won't need to > > allocate more than X bytes to hold the data. > > > > We can play with the copy break value to tweak this. Thanks Michael, now it is perfectly clear. It seems an excellent solution and easy to implement. I'll work on that. > > This seems like a reasonable solution. Hopefully the benchmark results > will come out okay too. Yes, as Michael suggested I'll play with the copy break value to see as benchmark has affected. Thank you very much, Stefano
