On 01/08/2016 09:15 PM, Vincenzo Maffione wrote:
> With this patch, nm_open() does not mmap() the netmap device. This
> operation is performed separately only if the memory area of the
> port just opened was not known before.
> A global list of netmap clients is kept to check when matches
> occur.
>
> Signed-off-by: Vincenzo Maffione <v.maffi...@gmail.com>
> ---
> net/netmap.c | 38 +++++++++++++++++++++++++++++++++++++-
> 1 file changed, 37 insertions(+), 1 deletion(-)
>
> diff --git a/net/netmap.c b/net/netmap.c
> index 27295ab..6a4c01c 100644
> --- a/net/netmap.c
> +++ b/net/netmap.c
> @@ -49,8 +49,12 @@ typedef struct NetmapState {
> bool write_poll;
> struct iovec iov[IOV_MAX];
> int vnet_hdr_len; /* Current virtio-net header length.
> */
> + QTAILQ_ENTRY(NetmapState) next;
> } NetmapState;
>
> +static QTAILQ_HEAD(, NetmapState) netmap_clients =
> + QTAILQ_HEAD_INITIALIZER(netmap_clients);
> +
> #ifndef __FreeBSD__
> #define pkt_copy bcopy
> #else
> @@ -78,6 +82,23 @@ pkt_copy(const void *_src, void *_dst, int l)
> #endif /* __FreeBSD__ */
>
> /*
> + * find nm_desc parent with same allocator
> + */
> +static struct nm_desc *
> +netmap_find_memory(struct nm_desc *nmd)
> +{
> + NetmapState *s;
> +
> + QTAILQ_FOREACH(s, &netmap_clients, next) {
> + if (nmd->req.nr_arg2 == s->nmd->req.nr_arg2) {
> + return s->nmd;
> + }
> + }
> +
> + return NULL;
> +}
> +
> +/*
> * Open a netmap device. We assume there is only one queue
> * (which is the case for the VALE bridge).
> */
> @@ -86,10 +107,11 @@ static struct nm_desc *netmap_open(const
> NetdevNetmapOptions *nm_opts,
> {
> struct nm_desc *nmd;
> struct nmreq req;
> + int ret;
>
> memset(&req, 0, sizeof(req));
>
> - nmd = nm_open(nm_opts->ifname, &req, NETMAP_NO_TX_POLL,
> + nmd = nm_open(nm_opts->ifname, &req, NETMAP_NO_TX_POLL | NM_OPEN_NO_MMAP,
> NULL);
> if (nmd == NULL) {
> error_setg_errno(errp, errno, "Failed to nm_open() %s",
> @@ -97,6 +119,17 @@ static struct nm_desc *netmap_open(const
> NetdevNetmapOptions *nm_opts,
> return NULL;
> }
>
> + /* Check if we already have a nm_desc that uses the same memory as the
> one
> + * just opened, so that nm_mmap() can skip mmap() and inherit from
> parent.
> + */
> + ret = nm_mmap(nmd, netmap_find_memory(nmd));
Looks like I could not find nm_mmap() definition in neither qemu or
freebsd source. Is there anything missed?
> + if (ret) {
> + error_setg_errno(errp, errno, "Failed to nm_mmap() %s",
> + nm_opts->ifname);
> + nm_close(nmd);
> + return NULL;
> + }
> +
> return nmd;
> }
>
> @@ -321,6 +354,8 @@ static void netmap_cleanup(NetClientState *nc)
> netmap_poll(nc, false);
> nm_close(s->nmd);
> s->nmd = NULL;
> +
> + QTAILQ_REMOVE(&netmap_clients, s, next);
> }
>
> /* Offloading manipulation support callbacks. */
> @@ -423,6 +458,7 @@ int net_init_netmap(const NetClientOptions *opts,
> s->rx = NETMAP_RXRING(nmd->nifp, 0);
> s->vnet_hdr_len = 0;
> pstrcpy(s->ifname, sizeof(s->ifname), netmap_opts->ifname);
> + QTAILQ_INSERT_TAIL(&netmap_clients, s, next);
> netmap_read_poll(s, true); /* Initially only poll for reads. */
>
> return 0;
