Resubmit the patch with most update. This patch passed some live-migration test against RHEL6.2. I will run more stress test w/i live migration.
Signed-off-by: Shirley Ma <[email protected]> --- drivers/vhost/net.c | 37 +++++++++++++++++++++++++++++++- drivers/vhost/vhost.c | 55 ++++++++++++++++++++++++++++++++++++++++++++++++- drivers/vhost/vhost.h | 12 ++++++++++ 3 files changed, 101 insertions(+), 3 deletions(-) diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c index 2f7c76a..6bd6e28 100644 --- a/drivers/vhost/net.c +++ b/drivers/vhost/net.c @@ -32,6 +32,9 @@ * Using this limit prevents one virtqueue from starving others. */ #define VHOST_NET_WEIGHT 0x80000 +/* MAX number of TX used buffers for outstanding zerocopy */ +#define VHOST_MAX_ZEROCOPY_PEND 128 + enum { VHOST_NET_VQ_RX = 0, VHOST_NET_VQ_TX = 1, @@ -129,6 +132,7 @@ static void handle_tx(struct vhost_net *net) int err, wmem; size_t hdr_size; struct socket *sock; + struct skb_ubuf_info pend; /* TODO: check that we are running from vhost_worker? */ sock = rcu_dereference_check(vq->private_data, 1); @@ -151,6 +155,10 @@ static void handle_tx(struct vhost_net *net) hdr_size = vq->vhost_hlen; for (;;) { + /* Release DMAs done buffers first */ + if (atomic_read(&vq->refcnt) > VHOST_MAX_ZEROCOPY_PEND) + vhost_zerocopy_signal_used(vq, false); + head = vhost_get_vq_desc(&net->dev, vq, vq->iov, ARRAY_SIZE(vq->iov), &out, &in, @@ -166,6 +174,13 @@ static void handle_tx(struct vhost_net *net) set_bit(SOCK_ASYNC_NOSPACE, &sock->flags); break; } + /* If more outstanding DMAs, queue the work */ + if (sock_flag(sock->sk, SOCK_ZEROCOPY) && + (atomic_read(&vq->refcnt) > VHOST_MAX_ZEROCOPY_PEND)) { + tx_poll_start(net, sock); + set_bit(SOCK_ASYNC_NOSPACE, &sock->flags); + break; + } if (unlikely(vhost_enable_notify(vq))) { vhost_disable_notify(vq); continue; @@ -188,17 +203,35 @@ static void handle_tx(struct vhost_net *net) iov_length(vq->hdr, s), hdr_size); break; } + /* use msg_control to pass vhost zerocopy ubuf info to skb */ + if (sock_flag(sock->sk, SOCK_ZEROCOPY)) { + vq->heads[vq->upend_idx].id = head; + if (len <= 128) + vq->heads[vq->upend_idx].len = VHOST_DMA_DONE_LEN; + else { + vq->heads[vq->upend_idx].len = len; + pend.callback = vhost_zerocopy_callback; + pend.arg = vq; + pend.desc = vq->upend_idx; + msg.msg_control = &pend; + msg.msg_controllen = sizeof(pend); + } + atomic_inc(&vq->refcnt); + vq->upend_idx = (vq->upend_idx + 1) % UIO_MAXIOV; + } /* TODO: Check specific error and bomb out unless ENOBUFS? */ err = sock->ops->sendmsg(NULL, sock, &msg, len); if (unlikely(err < 0)) { - vhost_discard_vq_desc(vq, 1); + if (!sock_flag(sock->sk, SOCK_ZEROCOPY)) + vhost_discard_vq_desc(vq, 1); tx_poll_start(net, sock); break; } if (err != len) pr_debug("Truncated TX packet: " " len %d != %zd\n", err, len); - vhost_add_used_and_signal(&net->dev, vq, head, 0); + if (!sock_flag(sock->sk, SOCK_ZEROCOPY)) + vhost_add_used_and_signal(&net->dev, vq, head, 0); total_len += len; if (unlikely(total_len >= VHOST_NET_WEIGHT)) { vhost_poll_queue(&vq->poll); diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c index 2ab2912..ce799d6 100644 --- a/drivers/vhost/vhost.c +++ b/drivers/vhost/vhost.c @@ -174,6 +174,9 @@ static void vhost_vq_reset(struct vhost_dev *dev, vq->call_ctx = NULL; vq->call = NULL; vq->log_ctx = NULL; + vq->upend_idx = 0; + vq->done_idx = 0; + atomic_set(&vq->refcnt, 0); } static int vhost_worker(void *data) @@ -230,7 +233,7 @@ static long vhost_dev_alloc_iovecs(struct vhost_dev *dev) UIO_MAXIOV, GFP_KERNEL); dev->vqs[i].log = kmalloc(sizeof *dev->vqs[i].log * UIO_MAXIOV, GFP_KERNEL); - dev->vqs[i].heads = kmalloc(sizeof *dev->vqs[i].heads * + dev->vqs[i].heads = kzalloc(sizeof *dev->vqs[i].heads * UIO_MAXIOV, GFP_KERNEL); if (!dev->vqs[i].indirect || !dev->vqs[i].log || @@ -385,6 +388,38 @@ long vhost_dev_reset_owner(struct vhost_dev *dev) return 0; } +/* + comments +*/ +void vhost_zerocopy_signal_used(struct vhost_virtqueue *vq, bool shutdown) +{ + int i, j = 0; + + i = vq->done_idx; + while (i != vq->upend_idx) { + if ((vq->heads[i].len == VHOST_DMA_DONE_LEN) || shutdown) { + /* reset len = 0 */ + vq->heads[i].len = 0; + i = (i + 1) % UIO_MAXIOV; + ++j; + } else + break; + } + if (j) { + /* comments */ + if (i > vq->done_idx) + vhost_add_used_n(vq, &vq->heads[vq->done_idx], j); + else { + vhost_add_used_n(vq, &vq->heads[vq->done_idx], + UIO_MAXIOV - vq->done_idx); + vhost_add_used_n(vq, vq->heads, i); + } + vq->done_idx = i; + vhost_signal(vq->dev, vq); + atomic_sub(j, &vq->refcnt); + } +} + /* Caller should have device mutex */ void vhost_dev_cleanup(struct vhost_dev *dev) { @@ -395,6 +430,11 @@ void vhost_dev_cleanup(struct vhost_dev *dev) vhost_poll_stop(&dev->vqs[i].poll); vhost_poll_flush(&dev->vqs[i].poll); } + /* wait for all lower device DMAs done, then notify guest */ + if (atomic_read(&dev->vqs[i].refcnt)) { + msleep(1000); + vhost_zerocopy_signal_used(&dev->vqs[i], true); + } if (dev->vqs[i].error_ctx) eventfd_ctx_put(dev->vqs[i].error_ctx); if (dev->vqs[i].error) @@ -603,6 +643,10 @@ static long vhost_set_vring(struct vhost_dev *d, int ioctl, void __user *argp) mutex_lock(&vq->mutex); + /* force all lower device DMAs done */ + if (atomic_read(&vq->refcnt)) + vhost_zerocopy_signal_used(vq, true); + switch (ioctl) { case VHOST_SET_VRING_NUM: /* Resizing ring with an active backend? @@ -1416,3 +1460,12 @@ void vhost_disable_notify(struct vhost_virtqueue *vq) vq_err(vq, "Failed to enable notification at %p: %d\n", &vq->used->flags, r); } + +void vhost_zerocopy_callback(struct sk_buff *skb) +{ + int idx = skb_shinfo(skb)->ubuf.desc; + struct vhost_virtqueue *vq = skb_shinfo(skb)->ubuf.arg; + + /* set len = 1 to mark this desc buffers done DMA */ + vq->heads[idx].len = VHOST_DMA_DONE_LEN; +} diff --git a/drivers/vhost/vhost.h b/drivers/vhost/vhost.h index b3363ae..8e3ecc7 100644 --- a/drivers/vhost/vhost.h +++ b/drivers/vhost/vhost.h @@ -13,6 +13,10 @@ #include <linux/virtio_ring.h> #include <asm/atomic.h> +/* This is for zerocopy, used buffer len is set to 1 when lower device DMA + * done */ +#define VHOST_DMA_DONE_LEN 1 + struct vhost_device; struct vhost_work; @@ -108,6 +112,12 @@ struct vhost_virtqueue { /* Log write descriptors */ void __user *log_base; struct vhost_log *log; + /* vhost zerocopy support */ + atomic_t refcnt; /* num of outstanding zerocopy DMAs */ + /* copy of avail idx to monitor outstanding DMA zerocopy buffers */ + int upend_idx; + /* copy of used idx to monintor DMA done zerocopy buffers */ + int done_idx; }; struct vhost_dev { @@ -154,6 +164,8 @@ bool vhost_enable_notify(struct vhost_virtqueue *); int vhost_log_write(struct vhost_virtqueue *vq, struct vhost_log *log, unsigned int log_num, u64 len); +void vhost_zerocopy_callback(struct sk_buff *skb); +void vhost_zerocopy_signal_used(struct vhost_virtqueue *vq, bool shutdown); #define vq_err(vq, fmt, ...) do { \ pr_debug(pr_fmt(fmt), ##__VA_ARGS__); \ -- 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
