On Mon, Apr 22, 2013 at 08:32:27PM -0400, Sasha Levin wrote: > Support mergable rx buffers for virtio-net. This helps reduce the amount > of memory the guest kernel has to allocate per rx vq.
With this, we always do an extra copy of the rx data into a linear buffer. I am thinking about whether we should keep the non MRG_RXBUF code. For tap use case, it is fine, user can use vhost. But for uip use case, we can not use vhost. > Signed-off-by: Sasha Levin <[email protected]> > --- > tools/kvm/include/kvm/uip.h | 4 ++-- > tools/kvm/include/kvm/util.h | 3 +++ > tools/kvm/net/uip/core.c | 54 > +++++--------------------------------------- > tools/kvm/net/uip/tcp.c | 2 +- > tools/kvm/net/uip/udp.c | 2 +- > tools/kvm/util/util.c | 15 ++++++++++++ > tools/kvm/virtio/net.c | 37 ++++++++++++++++++++++-------- > 7 files changed, 55 insertions(+), 62 deletions(-) > > diff --git a/tools/kvm/include/kvm/uip.h b/tools/kvm/include/kvm/uip.h > index ac248d2..fa82f10 100644 > --- a/tools/kvm/include/kvm/uip.h > +++ b/tools/kvm/include/kvm/uip.h > @@ -252,7 +252,7 @@ struct uip_tcp_socket { > }; > > struct uip_tx_arg { > - struct virtio_net_hdr *vnet; > + struct virtio_net_hdr_mrg_rxbuf *vnet; > struct uip_info *info; > struct uip_eth *eth; > int vnet_len; > @@ -332,7 +332,7 @@ static inline u16 uip_eth_hdrlen(struct uip_eth *eth) > } > > int uip_tx(struct iovec *iov, u16 out, struct uip_info *info); > -int uip_rx(struct iovec *iov, u16 in, struct uip_info *info); > +int uip_rx(unsigned char *buffer, u32 length, struct uip_info *info); > int uip_init(struct uip_info *info); > > int uip_tx_do_ipv4_udp_dhcp(struct uip_tx_arg *arg); > diff --git a/tools/kvm/include/kvm/util.h b/tools/kvm/include/kvm/util.h > index 0df9f0d..6f8ac83 100644 > --- a/tools/kvm/include/kvm/util.h > +++ b/tools/kvm/include/kvm/util.h > @@ -22,6 +22,7 @@ > #include <sys/param.h> > #include <sys/types.h> > #include <linux/types.h> > +#include <sys/uio.h> > > #ifdef __GNUC__ > #define NORETURN __attribute__((__noreturn__)) > @@ -94,4 +95,6 @@ struct kvm; > void *mmap_hugetlbfs(struct kvm *kvm, const char *htlbfs_path, u64 size); > void *mmap_anon_or_hugetlbfs(struct kvm *kvm, const char *hugetlbfs_path, > u64 size); > > +int memcpy_toiovecend(const struct iovec *iov, int iovlen, unsigned char > *kdata, size_t len); > + > #endif /* KVM__UTIL_H */ > diff --git a/tools/kvm/net/uip/core.c b/tools/kvm/net/uip/core.c > index 4e5bb82..d9e9993 100644 > --- a/tools/kvm/net/uip/core.c > +++ b/tools/kvm/net/uip/core.c > @@ -7,7 +7,7 @@ > > int uip_tx(struct iovec *iov, u16 out, struct uip_info *info) > { > - struct virtio_net_hdr *vnet; > + struct virtio_net_hdr_mrg_rxbuf *vnet; > struct uip_tx_arg arg; > int eth_len, vnet_len; > struct uip_eth *eth; > @@ -74,63 +74,21 @@ int uip_tx(struct iovec *iov, u16 out, struct uip_info > *info) > return vnet_len + eth_len; > } > > -int uip_rx(struct iovec *iov, u16 in, struct uip_info *info) > +int uip_rx(unsigned char *buffer, u32 length, struct uip_info *info) > { > - struct virtio_net_hdr *vnet; > - struct uip_eth *eth; > struct uip_buf *buf; > - int vnet_len; > - int eth_len; > - char *p; > int len; > - int cnt; > - int i; > > /* > * Sleep until there is a buffer for guest > */ > buf = uip_buf_get_used(info); > > - /* > - * Fill device to guest buffer, vnet hdr fisrt > - */ > - vnet_len = iov[0].iov_len; > - vnet = iov[0].iov_base; > - if (buf->vnet_len > vnet_len) { > - len = -1; > - goto out; > - } > - memcpy(vnet, buf->vnet, buf->vnet_len); > - > - /* > - * Then, the real eth data > - * Note: Be sure buf->eth_len is not bigger than the buffer len that > guest provides > - */ > - cnt = buf->eth_len; > - p = buf->eth; > - for (i = 1; i < in; i++) { > - eth_len = iov[i].iov_len; > - eth = iov[i].iov_base; > - if (cnt > eth_len) { > - memcpy(eth, p, eth_len); > - cnt -= eth_len; > - p += eth_len; > - } else { > - memcpy(eth, p, cnt); > - cnt -= cnt; > - break; > - } > - } > - > - if (cnt) { > - pr_warning("uip_rx error"); > - len = -1; > - goto out; > - } > + memcpy(buffer, buf->vnet, buf->vnet_len); > + memcpy(buffer + buf->vnet_len, buf->eth, buf->eth_len); > > len = buf->vnet_len + buf->eth_len; > > -out: > uip_buf_set_free(info, buf); > return len; > } > @@ -172,8 +130,8 @@ int uip_init(struct uip_info *info) > } > > list_for_each_entry(buf, buf_head, list) { > - buf->vnet = malloc(sizeof(struct virtio_net_hdr)); > - buf->vnet_len = sizeof(struct virtio_net_hdr); > + buf->vnet = malloc(sizeof(struct > virtio_net_hdr_mrg_rxbuf)); > + buf->vnet_len = sizeof(struct virtio_net_hdr_mrg_rxbuf); > buf->eth = malloc(1024*64 + sizeof(struct > uip_pseudo_hdr)); > buf->eth_len = 1024*64 + sizeof(struct uip_pseudo_hdr); > > diff --git a/tools/kvm/net/uip/tcp.c b/tools/kvm/net/uip/tcp.c > index 9044f40..a99b95e 100644 > --- a/tools/kvm/net/uip/tcp.c > +++ b/tools/kvm/net/uip/tcp.c > @@ -153,7 +153,7 @@ static int uip_tcp_payload_send(struct uip_tcp_socket > *sk, u8 flag, u16 payload_ > /* > * virtio_net_hdr > */ > - buf->vnet_len = sizeof(struct virtio_net_hdr); > + buf->vnet_len = sizeof(struct virtio_net_hdr_mrg_rxbuf); > memset(buf->vnet, 0, buf->vnet_len); > > buf->eth_len = ntohs(ip2->len) + uip_eth_hdrlen(&ip2->eth); > diff --git a/tools/kvm/net/uip/udp.c b/tools/kvm/net/uip/udp.c > index 31c417c..083c221 100644 > --- a/tools/kvm/net/uip/udp.c > +++ b/tools/kvm/net/uip/udp.c > @@ -142,7 +142,7 @@ int uip_udp_make_pkg(struct uip_info *info, struct > uip_udp_socket *sk, struct ui > /* > * virtio_net_hdr > */ > - buf->vnet_len = sizeof(struct virtio_net_hdr); > + buf->vnet_len = sizeof(struct virtio_net_hdr_mrg_rxbuf); > memset(buf->vnet, 0, buf->vnet_len); > > buf->eth_len = ntohs(ip2->len) + uip_eth_hdrlen(&ip2->eth); > diff --git a/tools/kvm/util/util.c b/tools/kvm/util/util.c > index c11a15a..4e0069c 100644 > --- a/tools/kvm/util/util.c > +++ b/tools/kvm/util/util.c > @@ -9,6 +9,7 @@ > #include <sys/mman.h> > #include <sys/stat.h> > #include <sys/statfs.h> > +#include <linux/kernel.h> > > static void report(const char *prefix, const char *err, va_list params) > { > @@ -131,3 +132,17 @@ void *mmap_anon_or_hugetlbfs(struct kvm *kvm, const char > *hugetlbfs_path, u64 si > return mmap(NULL, size, PROT_RW, MAP_ANON_NORESERVE, -1, 0); > } > } > + > +int memcpy_toiovecend(const struct iovec *iov, int iovlen, unsigned char > *kdata, size_t len) > +{ > + size_t copy, start_len = len; > + > + for (; len > 0 && iovlen > 0; ++iov, --iovlen) { > + copy = min(iov->iov_len, len); > + memcpy(iov->iov_base, kdata, copy); > + kdata += copy; > + len -= copy; > + } > + > + return start_len - len; > +} > diff --git a/tools/kvm/virtio/net.c b/tools/kvm/virtio/net.c > index c0a8f12..c99c5a6 100644 > --- a/tools/kvm/virtio/net.c > +++ b/tools/kvm/virtio/net.c > @@ -32,8 +32,8 @@ > struct net_dev; > > struct net_dev_operations { > - int (*rx)(struct iovec *iov, u16 in, struct net_dev *ndev); > - int (*tx)(struct iovec *iov, u16 in, struct net_dev *ndev); > + int (*rx)(unsigned char *buffer, u32 length, struct net_dev *ndev); > + int (*tx)(struct iovec *iov, u16 out, struct net_dev *ndev); > }; > > struct net_dev { > @@ -63,6 +63,8 @@ struct net_dev { > static LIST_HEAD(ndevs); > static int compat_id = -1; > > +#define MAX_PACKET_SIZE ((u16)(-1)) Why 64KB - 1? The package can be 65550 bytes which is max TCP or UDP plus 14 bytes eth header. > + > static void *virtio_net_rx_thread(void *p) > { > struct iovec iov[VIRTIO_NET_QUEUE_SIZE]; > @@ -90,9 +92,23 @@ static void *virtio_net_rx_thread(void *p) > mutex_unlock(&ndev->io_lock[id]); > > while (virt_queue__available(vq)) { > + unsigned char buffer[MAX_PACKET_SIZE]; The buffer size should at least be: MAX_PACKET_SIZE + sizeof(struct virtio_net_hdr_mrg_rxbuf) > + struct virtio_net_hdr_mrg_rxbuf *hdr; > + > + len = ndev->ops->rx(buffer, MAX_PACKET_SIZE, ndev); > head = virt_queue__get_iov(vq, iov, &out, &in, kvm); > - len = ndev->ops->rx(iov, in, ndev); > - virt_queue__set_used_elem(vq, head, len); > + hdr = (void *)iov[0].iov_base; > + while (len) { > + int copied; > + > + copied = memcpy_toiovecend(iov, in, buffer, > len); > + len -= copied; > + hdr->num_buffers++; > + virt_queue__set_used_elem(vq, head, copied); > + if (len == 0) > + break; > + head = virt_queue__get_iov(vq, iov, &out, &in, > kvm); Here, need to check if we still have available buffer from guest. If not need to wait for it. > + } > > /* We should interrupt guest right now, otherwise > latency is huge. */ > if (virtio_queue__should_signal(vq)) > @@ -241,7 +257,7 @@ static bool virtio_net__tap_init(const struct > virtio_net_params *params, > goto fail; > } > > - hdr_len = sizeof(struct virtio_net_hdr); > + hdr_len = sizeof(struct virtio_net_hdr_mrg_rxbuf); > if (ioctl(ndev->tap_fd, TUNSETVNETHDRSZ, &hdr_len) < 0) > pr_warning("Config tap device TUNSETVNETHDRSZ error"); > > @@ -300,9 +316,9 @@ static inline int tap_ops_tx(struct iovec *iov, u16 out, > struct net_dev *ndev) > return writev(ndev->tap_fd, iov, out); > } > > -static inline int tap_ops_rx(struct iovec *iov, u16 in, struct net_dev *ndev) > +static inline int tap_ops_rx(unsigned char *buffer, u32 length, struct > net_dev *ndev) > { > - return readv(ndev->tap_fd, iov, in); > + return read(ndev->tap_fd, buffer, length); > } > > static inline int uip_ops_tx(struct iovec *iov, u16 out, struct net_dev > *ndev) > @@ -310,9 +326,9 @@ static inline int uip_ops_tx(struct iovec *iov, u16 out, > struct net_dev *ndev) > return uip_tx(iov, out, &ndev->info); > } > > -static inline int uip_ops_rx(struct iovec *iov, u16 in, struct net_dev *ndev) > +static inline int uip_ops_rx(unsigned char *buffer, u32 length, struct > net_dev *ndev) > { > - return uip_rx(iov, in, &ndev->info); > + return uip_rx(buffer, length, &ndev->info); > } > > static struct net_dev_operations tap_ops = { > @@ -347,7 +363,8 @@ static u32 get_host_features(struct kvm *kvm, void *dev) > | 1UL << VIRTIO_RING_F_EVENT_IDX > | 1UL << VIRTIO_RING_F_INDIRECT_DESC > | 1UL << VIRTIO_NET_F_CTRL_VQ > - | 1UL << (ndev->queue_pairs > 1 ? VIRTIO_NET_F_MQ : 0); > + | 1UL << (ndev->queue_pairs > 1 ? VIRTIO_NET_F_MQ : 0) > + | 1UL << VIRTIO_NET_F_MRG_RXBUF; > } > > static void set_guest_features(struct kvm *kvm, void *dev, u32 features) > -- > 1.8.2.1 > -- Asias -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
