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Date: Mon, 28 Feb 2011 12:04:23 +0200
From: "Michael S. Tsirkin" <mst@...hat.com>
To: Krishna Kumar <krkumar2@...ibm.com>
Cc: rusty@...tcorp.com.au, davem@...emloft.net, eric.dumazet@...il.com,
arnd@...db.de, netdev@...r.kernel.org, horms@...ge.net.au,
avi@...hat.com, anthony@...emonkey.ws, kvm@...r.kernel.org
Subject: Re: [PATCH 3/3] [RFC] Changes for MQ vhost
On Mon, Feb 28, 2011 at 12:04:43PM +0530, Krishna Kumar wrote:
> Changes for mq vhost.
>
> vhost_net_open is changed to allocate a vhost_net and return.
> The remaining initializations are delayed till SET_OWNER.
> SET_OWNER is changed so that the argument is used to determine
> how many txqs to use. Unmodified qemu's will pass NULL, so
> this is recognized and handled as numtxqs=1.
>
> The number of vhost threads is <= #txqs. Threads handle more
> than one txq when #txqs is more than MAX_VHOST_THREADS (4).
It is this sharing that prevents us from just reusing multiple vhost
descriptors? 4 seems a bit arbitrary - do you have an explanation
on why this is a good number?
> The same thread handles both RX and TX - tested with tap/bridge
> so far (TBD: needs some changes in macvtap driver to support
> the same).
>
> I had to convert space->tab in vhost_attach_cgroups* to avoid
> checkpatch errors.
Separate patch pls, I'll apply that right away.
>
> Signed-off-by: Krishna Kumar <krkumar2@...ibm.com>
> ---
> drivers/vhost/net.c | 295 ++++++++++++++++++++++++++--------------
> drivers/vhost/vhost.c | 225 +++++++++++++++++++-----------
> drivers/vhost/vhost.h | 39 ++++-
> 3 files changed, 378 insertions(+), 181 deletions(-)
>
> diff -ruNp org/drivers/vhost/vhost.h new/drivers/vhost/vhost.h
> --- org/drivers/vhost/vhost.h 2011-02-08 09:05:09.000000000 +0530
> +++ new/drivers/vhost/vhost.h 2011-02-28 11:48:06.000000000 +0530
> @@ -35,11 +35,11 @@ struct vhost_poll {
> wait_queue_t wait;
> struct vhost_work work;
> unsigned long mask;
> - struct vhost_dev *dev;
> + struct vhost_virtqueue *vq; /* points back to vq */
> };
>
> void vhost_poll_init(struct vhost_poll *poll, vhost_work_fn_t fn,
> - unsigned long mask, struct vhost_dev *dev);
> + unsigned long mask, struct vhost_virtqueue *vq);
> void vhost_poll_start(struct vhost_poll *poll, struct file *file);
> void vhost_poll_stop(struct vhost_poll *poll);
> void vhost_poll_flush(struct vhost_poll *poll);
> @@ -108,8 +108,14 @@ struct vhost_virtqueue {
> /* Log write descriptors */
> void __user *log_base;
> struct vhost_log *log;
> + struct task_struct *worker; /* worker for this vq */
> + spinlock_t *work_lock; /* points to a dev->work_lock[] entry */
> + struct list_head *work_list; /* points to a dev->work_list[] entry */
> + int qnum; /* 0 for RX, 1 -> n-1 for TX */
Is this right?
> };
>
> +#define MAX_VHOST_THREADS 4
> +
> struct vhost_dev {
> /* Readers use RCU to access memory table pointer
> * log base pointer and features.
> @@ -122,12 +128,33 @@ struct vhost_dev {
> int nvqs;
> struct file *log_file;
> struct eventfd_ctx *log_ctx;
> - spinlock_t work_lock;
> - struct list_head work_list;
> - struct task_struct *worker;
> + spinlock_t *work_lock[MAX_VHOST_THREADS];
> + struct list_head *work_list[MAX_VHOST_THREADS];
This looks a bit strange. Won't sticking everything in a single
array of structures rather than multiple arrays be better for cache
utilization?
> };
>
> -long vhost_dev_init(struct vhost_dev *, struct vhost_virtqueue *vqs, int nvqs);
> +/*
> + * Return maximum number of vhost threads needed to handle RX & TX.
> + * Upto MAX_VHOST_THREADS are started, and threads can be shared
> + * among different vq's if numtxqs > MAX_VHOST_THREADS.
> + */
> +static inline int get_nvhosts(int nvqs)
nvhosts -> nthreads?
> +{
> + return min_t(int, nvqs / 2, MAX_VHOST_THREADS);
> +}
> +
> +/*
> + * Get index of an existing thread that will handle this txq/rxq.
> + * The same thread handles both rx[index] and tx[index].
> + */
> +static inline int vhost_get_thread_index(int index, int numtxqs, int nvhosts)
> +{
> + return (index % numtxqs) % nvhosts;
> +}
> +
As the only caller passes MAX_VHOST_THREADS,
just use that?
> +int vhost_setup_vqs(struct vhost_dev *dev, int numtxqs);
> +void vhost_free_vqs(struct vhost_dev *dev);
> +long vhost_dev_init(struct vhost_dev *, struct vhost_virtqueue *vqs, int nvqs,
> + int nvhosts);
> long vhost_dev_check_owner(struct vhost_dev *);
> long vhost_dev_reset_owner(struct vhost_dev *);
> void vhost_dev_cleanup(struct vhost_dev *);
> diff -ruNp org/drivers/vhost/net.c new/drivers/vhost/net.c
> --- org/drivers/vhost/net.c 2011-02-08 09:05:09.000000000 +0530
> +++ new/drivers/vhost/net.c 2011-02-28 11:48:53.000000000 +0530
> @@ -32,12 +32,6 @@
> * Using this limit prevents one virtqueue from starving others. */
> #define VHOST_NET_WEIGHT 0x80000
>
> -enum {
> - VHOST_NET_VQ_RX = 0,
> - VHOST_NET_VQ_TX = 1,
> - VHOST_NET_VQ_MAX = 2,
> -};
> -
> enum vhost_net_poll_state {
> VHOST_NET_POLL_DISABLED = 0,
> VHOST_NET_POLL_STARTED = 1,
> @@ -46,12 +40,13 @@ enum vhost_net_poll_state {
>
> struct vhost_net {
> struct vhost_dev dev;
> - struct vhost_virtqueue vqs[VHOST_NET_VQ_MAX];
> - struct vhost_poll poll[VHOST_NET_VQ_MAX];
> + struct vhost_virtqueue *vqs;
> + struct vhost_poll *poll;
> + struct socket **socks;
> /* Tells us whether we are polling a socket for TX.
> * We only do this when socket buffer fills up.
> * Protected by tx vq lock. */
> - enum vhost_net_poll_state tx_poll_state;
> + enum vhost_net_poll_state *tx_poll_state;
another array?
> };
>
> /* Pop first len bytes from iovec. Return number of segments used. */
> @@ -91,28 +86,28 @@ static void copy_iovec_hdr(const struct
> }
>
> /* Caller must have TX VQ lock */
> -static void tx_poll_stop(struct vhost_net *net)
> +static void tx_poll_stop(struct vhost_net *net, int qnum)
> {
> - if (likely(net->tx_poll_state != VHOST_NET_POLL_STARTED))
> + if (likely(net->tx_poll_state[qnum] != VHOST_NET_POLL_STARTED))
> return;
> - vhost_poll_stop(net->poll + VHOST_NET_VQ_TX);
> - net->tx_poll_state = VHOST_NET_POLL_STOPPED;
> + vhost_poll_stop(&net->poll[qnum]);
> + net->tx_poll_state[qnum] = VHOST_NET_POLL_STOPPED;
> }
>
> /* Caller must have TX VQ lock */
> -static void tx_poll_start(struct vhost_net *net, struct socket *sock)
> +static void tx_poll_start(struct vhost_net *net, struct socket *sock, int qnum)
> {
> - if (unlikely(net->tx_poll_state != VHOST_NET_POLL_STOPPED))
> + if (unlikely(net->tx_poll_state[qnum] != VHOST_NET_POLL_STOPPED))
> return;
> - vhost_poll_start(net->poll + VHOST_NET_VQ_TX, sock->file);
> - net->tx_poll_state = VHOST_NET_POLL_STARTED;
> + vhost_poll_start(&net->poll[qnum], sock->file);
> + net->tx_poll_state[qnum] = VHOST_NET_POLL_STARTED;
> }
>
> /* Expects to be always run from workqueue - which acts as
> * read-size critical section for our kind of RCU. */
> -static void handle_tx(struct vhost_net *net)
> +static void handle_tx(struct vhost_virtqueue *vq)
> {
> - struct vhost_virtqueue *vq = &net->dev.vqs[VHOST_NET_VQ_TX];
> + struct vhost_net *net = container_of(vq->dev, struct vhost_net, dev);
> unsigned out, in, s;
> int head;
> struct msghdr msg = {
> @@ -136,7 +131,7 @@ static void handle_tx(struct vhost_net *
> wmem = atomic_read(&sock->sk->sk_wmem_alloc);
> if (wmem >= sock->sk->sk_sndbuf) {
> mutex_lock(&vq->mutex);
> - tx_poll_start(net, sock);
> + tx_poll_start(net, sock, vq->qnum);
> mutex_unlock(&vq->mutex);
> return;
> }
> @@ -145,7 +140,7 @@ static void handle_tx(struct vhost_net *
> vhost_disable_notify(vq);
>
> if (wmem < sock->sk->sk_sndbuf / 2)
> - tx_poll_stop(net);
> + tx_poll_stop(net, vq->qnum);
> hdr_size = vq->vhost_hlen;
>
> for (;;) {
> @@ -160,7 +155,7 @@ static void handle_tx(struct vhost_net *
> if (head == vq->num) {
> wmem = atomic_read(&sock->sk->sk_wmem_alloc);
> if (wmem >= sock->sk->sk_sndbuf * 3 / 4) {
> - tx_poll_start(net, sock);
> + tx_poll_start(net, sock, vq->qnum);
> set_bit(SOCK_ASYNC_NOSPACE, &sock->flags);
> break;
> }
> @@ -190,7 +185,7 @@ static void handle_tx(struct vhost_net *
> err = sock->ops->sendmsg(NULL, sock, &msg, len);
> if (unlikely(err < 0)) {
> vhost_discard_vq_desc(vq, 1);
> - tx_poll_start(net, sock);
> + tx_poll_start(net, sock, vq->qnum);
> break;
> }
> if (err != len)
> @@ -282,9 +277,9 @@ err:
>
> /* Expects to be always run from workqueue - which acts as
> * read-size critical section for our kind of RCU. */
> -static void handle_rx_big(struct vhost_net *net)
> +static void handle_rx_big(struct vhost_virtqueue *vq,
> + struct vhost_net *net)
> {
> - struct vhost_virtqueue *vq = &net->dev.vqs[VHOST_NET_VQ_RX];
> unsigned out, in, log, s;
> int head;
> struct vhost_log *vq_log;
> @@ -392,9 +387,9 @@ static void handle_rx_big(struct vhost_n
>
> /* Expects to be always run from workqueue - which acts as
> * read-size critical section for our kind of RCU. */
> -static void handle_rx_mergeable(struct vhost_net *net)
> +static void handle_rx_mergeable(struct vhost_virtqueue *vq,
> + struct vhost_net *net)
> {
> - struct vhost_virtqueue *vq = &net->dev.vqs[VHOST_NET_VQ_RX];
> unsigned uninitialized_var(in), log;
> struct vhost_log *vq_log;
> struct msghdr msg = {
> @@ -498,99 +493,196 @@ static void handle_rx_mergeable(struct v
> mutex_unlock(&vq->mutex);
> }
>
> -static void handle_rx(struct vhost_net *net)
> +static void handle_rx(struct vhost_virtqueue *vq)
> {
> + struct vhost_net *net = container_of(vq->dev, struct vhost_net, dev);
> +
> if (vhost_has_feature(&net->dev, VIRTIO_NET_F_MRG_RXBUF))
> - handle_rx_mergeable(net);
> + handle_rx_mergeable(vq, net);
> else
> - handle_rx_big(net);
> + handle_rx_big(vq, net);
> }
>
> static void handle_tx_kick(struct vhost_work *work)
> {
> struct vhost_virtqueue *vq = container_of(work, struct vhost_virtqueue,
> poll.work);
> - struct vhost_net *net = container_of(vq->dev, struct vhost_net, dev);
>
> - handle_tx(net);
> + handle_tx(vq);
> }
>
> static void handle_rx_kick(struct vhost_work *work)
> {
> struct vhost_virtqueue *vq = container_of(work, struct vhost_virtqueue,
> poll.work);
> - struct vhost_net *net = container_of(vq->dev, struct vhost_net, dev);
>
> - handle_rx(net);
> + handle_rx(vq);
> }
>
> static void handle_tx_net(struct vhost_work *work)
> {
> - struct vhost_net *net = container_of(work, struct vhost_net,
> - poll[VHOST_NET_VQ_TX].work);
> - handle_tx(net);
> + struct vhost_virtqueue *vq = container_of(work, struct vhost_poll,
> + work)->vq;
> +
> + handle_tx(vq);
> }
>
> static void handle_rx_net(struct vhost_work *work)
> {
> - struct vhost_net *net = container_of(work, struct vhost_net,
> - poll[VHOST_NET_VQ_RX].work);
> - handle_rx(net);
> + struct vhost_virtqueue *vq = container_of(work, struct vhost_poll,
> + work)->vq;
> +
> + handle_rx(vq);
> }
>
> -static int vhost_net_open(struct inode *inode, struct file *f)
> +void vhost_free_vqs(struct vhost_dev *dev)
> {
> - struct vhost_net *n = kmalloc(sizeof *n, GFP_KERNEL);
> - struct vhost_dev *dev;
> - int r;
> + struct vhost_net *n = container_of(dev, struct vhost_net, dev);
> + int i;
>
> - if (!n)
> - return -ENOMEM;
> + if (!n->vqs)
> + return;
>
> - dev = &n->dev;
> - n->vqs[VHOST_NET_VQ_TX].handle_kick = handle_tx_kick;
> - n->vqs[VHOST_NET_VQ_RX].handle_kick = handle_rx_kick;
> - r = vhost_dev_init(dev, n->vqs, VHOST_NET_VQ_MAX);
> - if (r < 0) {
> - kfree(n);
> - return r;
> + /* vhost_net_open does kzalloc, so this loop will not panic */
> + for (i = 0; i < get_nvhosts(dev->nvqs); i++) {
> + kfree(dev->work_list[i]);
> + kfree(dev->work_lock[i]);
> }
>
> - vhost_poll_init(n->poll + VHOST_NET_VQ_TX, handle_tx_net, POLLOUT, dev);
> - vhost_poll_init(n->poll + VHOST_NET_VQ_RX, handle_rx_net, POLLIN, dev);
> - n->tx_poll_state = VHOST_NET_POLL_DISABLED;
> + kfree(n->socks);
> + kfree(n->tx_poll_state);
> + kfree(n->poll);
> + kfree(n->vqs);
> +
> + /*
> + * Reset so that vhost_net_release (which gets called when
> + * vhost_dev_set_owner() call fails) will notice.
> + */
> + n->vqs = NULL;
> +}
>
> - f->private_data = n;
> +int vhost_setup_vqs(struct vhost_dev *dev, int numtxqs)
> +{
> + struct vhost_net *n = container_of(dev, struct vhost_net, dev);
> + int nvhosts;
> + int i, nvqs;
> + int ret = -ENOMEM;
> +
> + if (numtxqs < 0 || numtxqs > VIRTIO_MAX_TXQS)
> + return -EINVAL;
> +
> + if (numtxqs == 0) {
> + /* Old qemu doesn't pass arguments to set_owner, use 1 txq */
> + numtxqs = 1;
> + }
> +
> + /* Get total number of virtqueues */
> + nvqs = numtxqs * 2;
> +
> + n->vqs = kmalloc(nvqs * sizeof(*n->vqs), GFP_KERNEL);
> + n->poll = kmalloc(nvqs * sizeof(*n->poll), GFP_KERNEL);
> + n->socks = kmalloc(nvqs * sizeof(*n->socks), GFP_KERNEL);
> + n->tx_poll_state = kmalloc(nvqs * sizeof(*n->tx_poll_state),
> + GFP_KERNEL);
> + if (!n->vqs || !n->poll || !n->socks || !n->tx_poll_state)
> + goto err;
> +
> + /* Get total number of vhost threads */
> + nvhosts = get_nvhosts(nvqs);
> +
> + for (i = 0; i < nvhosts; i++) {
> + dev->work_lock[i] = kmalloc(sizeof(*dev->work_lock[i]),
> + GFP_KERNEL);
> + dev->work_list[i] = kmalloc(sizeof(*dev->work_list[i]),
> + GFP_KERNEL);
> + if (!dev->work_lock[i] || !dev->work_list[i])
> + goto err;
> + if (((unsigned long) dev->work_lock[i] & (SMP_CACHE_BYTES - 1))
> + ||
> + ((unsigned long) dev->work_list[i] & SMP_CACHE_BYTES - 1))
> + pr_debug("Unaligned buffer @ %d - Lock: %p List: %p\n",
> + i, dev->work_lock[i], dev->work_list[i]);
> + }
> +
> + /* 'numtxqs' RX followed by 'numtxqs' TX queues */
> + for (i = 0; i < numtxqs; i++)
> + n->vqs[i].handle_kick = handle_rx_kick;
> + for (; i < nvqs; i++)
> + n->vqs[i].handle_kick = handle_tx_kick;
> +
> + ret = vhost_dev_init(dev, n->vqs, nvqs, nvhosts);
> + if (ret < 0)
> + goto err;
> +
> + for (i = 0; i < numtxqs; i++)
> + vhost_poll_init(&n->poll[i], handle_rx_net, POLLIN, &n->vqs[i]);
> +
> + for (; i < nvqs; i++) {
> + vhost_poll_init(&n->poll[i], handle_tx_net, POLLOUT,
> + &n->vqs[i]);
> + n->tx_poll_state[i] = VHOST_NET_POLL_DISABLED;
> + }
>
> return 0;
> +
> +err:
> + /* Free all pointers that may have been allocated */
> + vhost_free_vqs(dev);
> +
> + return ret;
> +}
> +
> +static int vhost_net_open(struct inode *inode, struct file *f)
> +{
> + struct vhost_net *n = kzalloc(sizeof *n, GFP_KERNEL);
> + int ret = -ENOMEM;
> +
> + if (n) {
> + struct vhost_dev *dev = &n->dev;
> +
> + f->private_data = n;
> + mutex_init(&dev->mutex);
> +
> + /* Defer all other initialization till user does SET_OWNER */
> + ret = 0;
> + }
> +
> + return ret;
> }
>
> static void vhost_net_disable_vq(struct vhost_net *n,
> struct vhost_virtqueue *vq)
> {
> + int qnum = vq->qnum;
> +
> if (!vq->private_data)
> return;
> - if (vq == n->vqs + VHOST_NET_VQ_TX) {
> - tx_poll_stop(n);
> - n->tx_poll_state = VHOST_NET_POLL_DISABLED;
> - } else
> - vhost_poll_stop(n->poll + VHOST_NET_VQ_RX);
> + if (qnum < n->dev.nvqs / 2) {
> + /* qnum is less than half, we are RX */
> + vhost_poll_stop(&n->poll[qnum]);
> + } else { /* otherwise we are TX */
> + tx_poll_stop(n, qnum);
> + n->tx_poll_state[qnum] = VHOST_NET_POLL_DISABLED;
> + }
> }
>
> static void vhost_net_enable_vq(struct vhost_net *n,
> struct vhost_virtqueue *vq)
> {
> struct socket *sock;
> + int qnum = vq->qnum;
>
> sock = rcu_dereference_protected(vq->private_data,
> lockdep_is_held(&vq->mutex));
> if (!sock)
> return;
> - if (vq == n->vqs + VHOST_NET_VQ_TX) {
> - n->tx_poll_state = VHOST_NET_POLL_STOPPED;
> - tx_poll_start(n, sock);
> - } else
> - vhost_poll_start(n->poll + VHOST_NET_VQ_RX, sock->file);
> + if (qnum < n->dev.nvqs / 2) {
> + /* qnum is less than half, we are RX */
> + vhost_poll_start(&n->poll[qnum], sock->file);
> + } else {
> + n->tx_poll_state[qnum] = VHOST_NET_POLL_STOPPED;
> + tx_poll_start(n, sock, qnum);
> + }
> }
>
> static struct socket *vhost_net_stop_vq(struct vhost_net *n,
> @@ -607,11 +699,12 @@ static struct socket *vhost_net_stop_vq(
> return sock;
> }
>
> -static void vhost_net_stop(struct vhost_net *n, struct socket **tx_sock,
> - struct socket **rx_sock)
> +static void vhost_net_stop(struct vhost_net *n)
> {
> - *tx_sock = vhost_net_stop_vq(n, n->vqs + VHOST_NET_VQ_TX);
> - *rx_sock = vhost_net_stop_vq(n, n->vqs + VHOST_NET_VQ_RX);
> + int i;
> +
> + for (i = n->dev.nvqs - 1; i >= 0; i--)
> + n->socks[i] = vhost_net_stop_vq(n, &n->vqs[i]);
> }
>
> static void vhost_net_flush_vq(struct vhost_net *n, int index)
> @@ -622,26 +715,33 @@ static void vhost_net_flush_vq(struct vh
>
> static void vhost_net_flush(struct vhost_net *n)
> {
> - vhost_net_flush_vq(n, VHOST_NET_VQ_TX);
> - vhost_net_flush_vq(n, VHOST_NET_VQ_RX);
> + int i;
> +
> + for (i = n->dev.nvqs - 1; i >= 0; i--)
> + vhost_net_flush_vq(n, i);
> }
>
> static int vhost_net_release(struct inode *inode, struct file *f)
> {
> struct vhost_net *n = f->private_data;
> - struct socket *tx_sock;
> - struct socket *rx_sock;
> + struct vhost_dev *dev = &n->dev;
> + int i;
>
> - vhost_net_stop(n, &tx_sock, &rx_sock);
> + vhost_net_stop(n);
> vhost_net_flush(n);
> - vhost_dev_cleanup(&n->dev);
> - if (tx_sock)
> - fput(tx_sock->file);
> - if (rx_sock)
> - fput(rx_sock->file);
> + vhost_dev_cleanup(dev);
> +
> + for (i = n->dev.nvqs - 1; i >= 0; i--)
> + if (n->socks[i])
> + fput(n->socks[i]->file);
> +
> /* We do an extra flush before freeing memory,
> * since jobs can re-queue themselves. */
> vhost_net_flush(n);
> +
> + /* Free all old pointers */
> + vhost_free_vqs(dev);
> +
> kfree(n);
> return 0;
> }
> @@ -719,7 +819,7 @@ static long vhost_net_set_backend(struct
> if (r)
> goto err;
>
> - if (index >= VHOST_NET_VQ_MAX) {
> + if (index >= n->dev.nvqs) {
> r = -ENOBUFS;
> goto err;
> }
> @@ -741,9 +841,9 @@ static long vhost_net_set_backend(struct
> oldsock = rcu_dereference_protected(vq->private_data,
> lockdep_is_held(&vq->mutex));
> if (sock != oldsock) {
> - vhost_net_disable_vq(n, vq);
> - rcu_assign_pointer(vq->private_data, sock);
> - vhost_net_enable_vq(n, vq);
> + vhost_net_disable_vq(n, vq);
> + rcu_assign_pointer(vq->private_data, sock);
> + vhost_net_enable_vq(n, vq);
> }
>
> mutex_unlock(&vq->mutex);
> @@ -765,22 +865,25 @@ err:
>
> static long vhost_net_reset_owner(struct vhost_net *n)
> {
> - struct socket *tx_sock = NULL;
> - struct socket *rx_sock = NULL;
> long err;
> + int i;
> +
> mutex_lock(&n->dev.mutex);
> err = vhost_dev_check_owner(&n->dev);
> - if (err)
> - goto done;
> - vhost_net_stop(n, &tx_sock, &rx_sock);
> + if (err) {
> + mutex_unlock(&n->dev.mutex);
> + return err;
> + }
> +
> + vhost_net_stop(n);
> vhost_net_flush(n);
> err = vhost_dev_reset_owner(&n->dev);
> -done:
> mutex_unlock(&n->dev.mutex);
> - if (tx_sock)
> - fput(tx_sock->file);
> - if (rx_sock)
> - fput(rx_sock->file);
> +
> + for (i = n->dev.nvqs - 1; i >= 0; i--)
> + if (n->socks[i])
> + fput(n->socks[i]->file);
> +
> return err;
> }
>
> @@ -809,7 +912,7 @@ static int vhost_net_set_features(struct
> }
> n->dev.acked_features = features;
> smp_wmb();
> - for (i = 0; i < VHOST_NET_VQ_MAX; ++i) {
> + for (i = 0; i < n->dev.nvqs; ++i) {
> mutex_lock(&n->vqs[i].mutex);
> n->vqs[i].vhost_hlen = vhost_hlen;
> n->vqs[i].sock_hlen = sock_hlen;
> diff -ruNp org/drivers/vhost/vhost.c new/drivers/vhost/vhost.c
> --- org/drivers/vhost/vhost.c 2011-01-19 20:01:29.000000000 +0530
> +++ new/drivers/vhost/vhost.c 2011-02-25 21:18:14.000000000 +0530
> @@ -70,12 +70,12 @@ static void vhost_work_init(struct vhost
>
> /* Init poll structure */
> void vhost_poll_init(struct vhost_poll *poll, vhost_work_fn_t fn,
> - unsigned long mask, struct vhost_dev *dev)
> + unsigned long mask, struct vhost_virtqueue *vq)
> {
> init_waitqueue_func_entry(&poll->wait, vhost_poll_wakeup);
> init_poll_funcptr(&poll->table, vhost_poll_func);
> poll->mask = mask;
> - poll->dev = dev;
> + poll->vq = vq;
>
> vhost_work_init(&poll->work, fn);
> }
> @@ -97,29 +97,30 @@ void vhost_poll_stop(struct vhost_poll *
> remove_wait_queue(poll->wqh, &poll->wait);
> }
>
> -static bool vhost_work_seq_done(struct vhost_dev *dev, struct vhost_work *work,
> - unsigned seq)
> +static bool vhost_work_seq_done(struct vhost_virtqueue *vq,
> + struct vhost_work *work, unsigned seq)
> {
> int left;
> - spin_lock_irq(&dev->work_lock);
> + spin_lock_irq(vq->work_lock);
> left = seq - work->done_seq;
> - spin_unlock_irq(&dev->work_lock);
> + spin_unlock_irq(vq->work_lock);
> return left <= 0;
> }
>
> -static void vhost_work_flush(struct vhost_dev *dev, struct vhost_work *work)
> +static void vhost_work_flush(struct vhost_virtqueue *vq,
> + struct vhost_work *work)
> {
> unsigned seq;
> int flushing;
>
> - spin_lock_irq(&dev->work_lock);
> + spin_lock_irq(vq->work_lock);
> seq = work->queue_seq;
> work->flushing++;
> - spin_unlock_irq(&dev->work_lock);
> - wait_event(work->done, vhost_work_seq_done(dev, work, seq));
> - spin_lock_irq(&dev->work_lock);
> + spin_unlock_irq(vq->work_lock);
> + wait_event(work->done, vhost_work_seq_done(vq, work, seq));
> + spin_lock_irq(vq->work_lock);
> flushing = --work->flushing;
> - spin_unlock_irq(&dev->work_lock);
> + spin_unlock_irq(vq->work_lock);
> BUG_ON(flushing < 0);
> }
>
> @@ -127,26 +128,26 @@ static void vhost_work_flush(struct vhos
> * locks that are also used by the callback. */
> void vhost_poll_flush(struct vhost_poll *poll)
> {
> - vhost_work_flush(poll->dev, &poll->work);
> + vhost_work_flush(poll->vq, &poll->work);
> }
>
> -static inline void vhost_work_queue(struct vhost_dev *dev,
> +static inline void vhost_work_queue(struct vhost_virtqueue *vq,
> struct vhost_work *work)
> {
> unsigned long flags;
>
> - spin_lock_irqsave(&dev->work_lock, flags);
> + spin_lock_irqsave(vq->work_lock, flags);
> if (list_empty(&work->node)) {
> - list_add_tail(&work->node, &dev->work_list);
> + list_add_tail(&work->node, vq->work_list);
> work->queue_seq++;
> - wake_up_process(dev->worker);
> + wake_up_process(vq->worker);
> }
> - spin_unlock_irqrestore(&dev->work_lock, flags);
> + spin_unlock_irqrestore(vq->work_lock, flags);
> }
>
> void vhost_poll_queue(struct vhost_poll *poll)
> {
> - vhost_work_queue(poll->dev, &poll->work);
> + vhost_work_queue(poll->vq, &poll->work);
> }
>
> static void vhost_vq_reset(struct vhost_dev *dev,
> @@ -176,17 +177,17 @@ static void vhost_vq_reset(struct vhost_
>
> static int vhost_worker(void *data)
> {
> - struct vhost_dev *dev = data;
> + struct vhost_virtqueue *vq = data;
> struct vhost_work *work = NULL;
> unsigned uninitialized_var(seq);
>
> - use_mm(dev->mm);
> + use_mm(vq->dev->mm);
>
> for (;;) {
> /* mb paired w/ kthread_stop */
> set_current_state(TASK_INTERRUPTIBLE);
>
> - spin_lock_irq(&dev->work_lock);
> + spin_lock_irq(vq->work_lock);
> if (work) {
> work->done_seq = seq;
> if (work->flushing)
> @@ -194,18 +195,18 @@ static int vhost_worker(void *data)
> }
>
> if (kthread_should_stop()) {
> - spin_unlock_irq(&dev->work_lock);
> + spin_unlock_irq(vq->work_lock);
> __set_current_state(TASK_RUNNING);
> break;
> }
> - if (!list_empty(&dev->work_list)) {
> - work = list_first_entry(&dev->work_list,
> + if (!list_empty(vq->work_list)) {
> + work = list_first_entry(vq->work_list,
> struct vhost_work, node);
> list_del_init(&work->node);
> seq = work->queue_seq;
> } else
> work = NULL;
> - spin_unlock_irq(&dev->work_lock);
> + spin_unlock_irq(vq->work_lock);
>
> if (work) {
> __set_current_state(TASK_RUNNING);
> @@ -214,7 +215,7 @@ static int vhost_worker(void *data)
> schedule();
>
> }
> - unuse_mm(dev->mm);
> + unuse_mm(vq->dev->mm);
> return 0;
> }
>
> @@ -258,7 +259,7 @@ static void vhost_dev_free_iovecs(struct
> }
>
> long vhost_dev_init(struct vhost_dev *dev,
> - struct vhost_virtqueue *vqs, int nvqs)
> + struct vhost_virtqueue *vqs, int nvqs, int nvhosts)
> {
> int i;
>
> @@ -269,20 +270,34 @@ long vhost_dev_init(struct vhost_dev *de
> dev->log_file = NULL;
> dev->memory = NULL;
> dev->mm = NULL;
> - spin_lock_init(&dev->work_lock);
> - INIT_LIST_HEAD(&dev->work_list);
> - dev->worker = NULL;
>
> for (i = 0; i < dev->nvqs; ++i) {
> - dev->vqs[i].log = NULL;
> - dev->vqs[i].indirect = NULL;
> - dev->vqs[i].heads = NULL;
> - dev->vqs[i].dev = dev;
> - mutex_init(&dev->vqs[i].mutex);
> + struct vhost_virtqueue *vq = &dev->vqs[i];
> + int j;
> +
> + if (i < nvhosts) {
> + spin_lock_init(dev->work_lock[i]);
> + INIT_LIST_HEAD(dev->work_list[i]);
> + j = i;
> + } else {
> + /* Share work with another thread */
> + j = vhost_get_thread_index(i, nvqs / 2, nvhosts);
> + }
> +
> + vq->work_lock = dev->work_lock[j];
> + vq->work_list = dev->work_list[j];
> +
> + vq->worker = NULL;
> + vq->qnum = i;
> + vq->log = NULL;
> + vq->indirect = NULL;
> + vq->heads = NULL;
> + vq->dev = dev;
> + mutex_init(&vq->mutex);
> vhost_vq_reset(dev, dev->vqs + i);
> - if (dev->vqs[i].handle_kick)
> - vhost_poll_init(&dev->vqs[i].poll,
> - dev->vqs[i].handle_kick, POLLIN, dev);
> + if (vq->handle_kick)
> + vhost_poll_init(&vq->poll,
> + vq->handle_kick, POLLIN, vq);
> }
>
> return 0;
> @@ -296,65 +311,124 @@ long vhost_dev_check_owner(struct vhost_
> }
>
> struct vhost_attach_cgroups_struct {
> - struct vhost_work work;
> - struct task_struct *owner;
> - int ret;
> + struct vhost_work work;
> + struct task_struct *owner;
> + int ret;
> };
>
> static void vhost_attach_cgroups_work(struct vhost_work *work)
> {
> - struct vhost_attach_cgroups_struct *s;
> - s = container_of(work, struct vhost_attach_cgroups_struct, work);
> - s->ret = cgroup_attach_task_all(s->owner, current);
> + struct vhost_attach_cgroups_struct *s;
> + s = container_of(work, struct vhost_attach_cgroups_struct, work);
> + s->ret = cgroup_attach_task_all(s->owner, current);
> +}
> +
> +static int vhost_attach_cgroups(struct vhost_virtqueue *vq)
> +{
> + struct vhost_attach_cgroups_struct attach;
> + attach.owner = current;
> + vhost_work_init(&attach.work, vhost_attach_cgroups_work);
> + vhost_work_queue(vq, &attach.work);
> + vhost_work_flush(vq, &attach.work);
> + return attach.ret;
> +}
> +
> +static void __vhost_stop_workers(struct vhost_dev *dev, int nvhosts)
> +{
> + int i;
> +
> + for (i = 0; i < nvhosts; i++) {
> + WARN_ON(!list_empty(dev->vqs[i].work_list));
> + if (dev->vqs[i].worker) {
> + kthread_stop(dev->vqs[i].worker);
> + dev->vqs[i].worker = NULL;
> + }
> + }
> +
> + if (dev->mm)
> + mmput(dev->mm);
> + dev->mm = NULL;
> +}
> +
> +static void vhost_stop_workers(struct vhost_dev *dev)
> +{
> + __vhost_stop_workers(dev, get_nvhosts(dev->nvqs));
> }
>
> -static int vhost_attach_cgroups(struct vhost_dev *dev)
> -{
> - struct vhost_attach_cgroups_struct attach;
> - attach.owner = current;
> - vhost_work_init(&attach.work, vhost_attach_cgroups_work);
> - vhost_work_queue(dev, &attach.work);
> - vhost_work_flush(dev, &attach.work);
> - return attach.ret;
> +static int vhost_start_workers(struct vhost_dev *dev)
> +{
> + int nvhosts = get_nvhosts(dev->nvqs);
> + int i, err;
> +
> + for (i = 0; i < dev->nvqs; ++i) {
> + struct vhost_virtqueue *vq = &dev->vqs[i];
> +
> + if (i < nvhosts) {
> + /* Start a new thread */
> + vq->worker = kthread_create(vhost_worker, vq,
> + "vhost-%d-%d",
> + current->pid, i);
> + if (IS_ERR(vq->worker)) {
> + i--; /* no thread to clean at this index */
> + err = PTR_ERR(vq->worker);
> + goto err;
> + }
> +
> + wake_up_process(vq->worker);
> +
> + /* avoid contributing to loadavg */
> + err = vhost_attach_cgroups(vq);
> + if (err)
> + goto err;
> + } else {
> + /* Share work with an existing thread */
> + int j = vhost_get_thread_index(i, dev->nvqs / 2,
> + nvhosts);
> +
> + vq->worker = dev->vqs[j].worker;
> + }
> + }
> + return 0;
> +
> +err:
> + __vhost_stop_workers(dev, i);
> + return err;
> }
>
> /* Caller should have device mutex */
> -static long vhost_dev_set_owner(struct vhost_dev *dev)
> +static long vhost_dev_set_owner(struct vhost_dev *dev, int numtxqs)
> {
> - struct task_struct *worker;
> int err;
> /* Is there an owner already? */
> if (dev->mm) {
> err = -EBUSY;
> goto err_mm;
> }
> +
> + err = vhost_setup_vqs(dev, numtxqs);
> + if (err)
> + goto err_mm;
> +
> /* No owner, become one */
> dev->mm = get_task_mm(current);
> - worker = kthread_create(vhost_worker, dev, "vhost-%d", current->pid);
> - if (IS_ERR(worker)) {
> - err = PTR_ERR(worker);
> - goto err_worker;
> - }
> -
> - dev->worker = worker;
> - wake_up_process(worker); /* avoid contributing to loadavg */
>
> - err = vhost_attach_cgroups(dev);
> + /* Start threads */
> + err = vhost_start_workers(dev);
> if (err)
> - goto err_cgroup;
> + goto free_vqs;
>
> err = vhost_dev_alloc_iovecs(dev);
> if (err)
> - goto err_cgroup;
> + goto clean_workers;
>
> return 0;
> -err_cgroup:
> - kthread_stop(worker);
> - dev->worker = NULL;
> -err_worker:
> +clean_workers:
> + vhost_stop_workers(dev);
> +free_vqs:
> if (dev->mm)
> mmput(dev->mm);
> dev->mm = NULL;
> + vhost_free_vqs(dev);
> err_mm:
> return err;
> }
> @@ -408,14 +482,7 @@ void vhost_dev_cleanup(struct vhost_dev
> kfree(rcu_dereference_protected(dev->memory,
> lockdep_is_held(&dev->mutex)));
> RCU_INIT_POINTER(dev->memory, NULL);
> - WARN_ON(!list_empty(&dev->work_list));
> - if (dev->worker) {
> - kthread_stop(dev->worker);
> - dev->worker = NULL;
> - }
> - if (dev->mm)
> - mmput(dev->mm);
> - dev->mm = NULL;
> + vhost_stop_workers(dev);
> }
>
> static int log_access_ok(void __user *log_base, u64 addr, unsigned long sz)
> @@ -775,7 +842,7 @@ long vhost_dev_ioctl(struct vhost_dev *d
>
> /* If you are not the owner, you can become one */
> if (ioctl == VHOST_SET_OWNER) {
> - r = vhost_dev_set_owner(d);
> + r = vhost_dev_set_owner(d, arg);
> goto done;
> }
>
--
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