#include <linux/scatterlist.h>
#include <linux/if_vlan.h>
#include <linux/slab.h>
+#include <linux/cpu.h>
static int napi_weight = 128;
module_param(napi_weight, int, 0444);
/* Does the affinity hint is set for virtqueues? */
bool affinity_hint_set;
+
+ /* Per-cpu variable to show the mapping from CPU to virtqueue */
+ int __percpu *vq_index;
+
+ /* CPU hot plug notifier */
+ struct notifier_block nb;
};
struct skb_vnet_hdr {
struct virtio_net_hdr hdr;
struct virtio_net_hdr_mrg_rxbuf mhdr;
};
- unsigned int num_sg;
};
struct padded_vnet_hdr {
err = add_recvbuf_small(rq, gfp);
oom = err == -ENOMEM;
- if (err < 0)
+ if (err)
break;
++rq->num;
- } while (err > 0);
+ } while (rq->vq->num_free);
if (unlikely(rq->num > rq->max))
rq->max = rq->num;
virtqueue_kick(rq->vq);
return 0;
}
-static unsigned int free_old_xmit_skbs(struct send_queue *sq)
+static void free_old_xmit_skbs(struct send_queue *sq)
{
struct sk_buff *skb;
- unsigned int len, tot_sgs = 0;
+ unsigned int len;
struct virtnet_info *vi = sq->vq->vdev->priv;
struct virtnet_stats *stats = this_cpu_ptr(vi->stats);
stats->tx_packets++;
u64_stats_update_end(&stats->tx_syncp);
- tot_sgs += skb_vnet_hdr(skb)->num_sg;
dev_kfree_skb_any(skb);
}
- return tot_sgs;
}
static int xmit_skb(struct send_queue *sq, struct sk_buff *skb)
struct skb_vnet_hdr *hdr = skb_vnet_hdr(skb);
const unsigned char *dest = ((struct ethhdr *)skb->data)->h_dest;
struct virtnet_info *vi = sq->vq->vdev->priv;
+ unsigned num_sg;
pr_debug("%s: xmit %p %pM\n", vi->dev->name, skb, dest);
else
sg_set_buf(sq->sg, &hdr->hdr, sizeof hdr->hdr);
- hdr->num_sg = skb_to_sgvec(skb, sq->sg + 1, 0, skb->len) + 1;
- return virtqueue_add_buf(sq->vq, sq->sg, hdr->num_sg,
+ num_sg = skb_to_sgvec(skb, sq->sg + 1, 0, skb->len) + 1;
+ return virtqueue_add_buf(sq->vq, sq->sg, num_sg,
0, skb, GFP_ATOMIC);
}
struct virtnet_info *vi = netdev_priv(dev);
int qnum = skb_get_queue_mapping(skb);
struct send_queue *sq = &vi->sq[qnum];
- int capacity;
+ int err;
/* Free up any pending old buffers before queueing new ones. */
free_old_xmit_skbs(sq);
/* Try to transmit */
- capacity = xmit_skb(sq, skb);
-
- /* This can happen with OOM and indirect buffers. */
- if (unlikely(capacity < 0)) {
- if (likely(capacity == -ENOMEM)) {
- if (net_ratelimit())
- dev_warn(&dev->dev,
- "TXQ (%d) failure: out of memory\n",
- qnum);
- } else {
- dev->stats.tx_fifo_errors++;
- if (net_ratelimit())
- dev_warn(&dev->dev,
- "Unexpected TXQ (%d) failure: %d\n",
- qnum, capacity);
- }
+ err = xmit_skb(sq, skb);
+
+ /* This should not happen! */
+ if (unlikely(err)) {
+ dev->stats.tx_fifo_errors++;
+ if (net_ratelimit())
+ dev_warn(&dev->dev,
+ "Unexpected TXQ (%d) queue failure: %d\n", qnum, err);
dev->stats.tx_dropped++;
kfree_skb(skb);
return NETDEV_TX_OK;
/* Apparently nice girls don't return TX_BUSY; stop the queue
* before it gets out of hand. Naturally, this wastes entries. */
- if (capacity < 2+MAX_SKB_FRAGS) {
+ if (sq->vq->num_free < 2+MAX_SKB_FRAGS) {
netif_stop_subqueue(dev, qnum);
if (unlikely(!virtqueue_enable_cb_delayed(sq->vq))) {
/* More just got used, free them then recheck. */
- capacity += free_old_xmit_skbs(sq);
- if (capacity >= 2+MAX_SKB_FRAGS) {
+ free_old_xmit_skbs(sq);
+ if (sq->vq->num_free >= 2+MAX_SKB_FRAGS) {
netif_start_subqueue(dev, qnum);
virtqueue_disable_cb(sq->vq);
}
return 0;
}
-static void virtnet_set_affinity(struct virtnet_info *vi, bool set)
+static void virtnet_clean_affinity(struct virtnet_info *vi, long hcpu)
{
int i;
+ int cpu;
+
+ if (vi->affinity_hint_set) {
+ for (i = 0; i < vi->max_queue_pairs; i++) {
+ virtqueue_set_affinity(vi->rq[i].vq, -1);
+ virtqueue_set_affinity(vi->sq[i].vq, -1);
+ }
+
+ vi->affinity_hint_set = false;
+ }
+
+ i = 0;
+ for_each_online_cpu(cpu) {
+ if (cpu == hcpu) {
+ *per_cpu_ptr(vi->vq_index, cpu) = -1;
+ } else {
+ *per_cpu_ptr(vi->vq_index, cpu) =
+ ++i % vi->curr_queue_pairs;
+ }
+ }
+}
+
+static void virtnet_set_affinity(struct virtnet_info *vi)
+{
+ int i;
+ int cpu;
/* In multiqueue mode, when the number of cpu is equal to the number of
* queue pairs, we let the queue pairs to be private to one cpu by
* setting the affinity hint to eliminate the contention.
*/
- if ((vi->curr_queue_pairs == 1 ||
- vi->max_queue_pairs != num_online_cpus()) && set) {
- if (vi->affinity_hint_set)
- set = false;
- else
- return;
+ if (vi->curr_queue_pairs == 1 ||
+ vi->max_queue_pairs != num_online_cpus()) {
+ virtnet_clean_affinity(vi, -1);
+ return;
}
- for (i = 0; i < vi->max_queue_pairs; i++) {
- int cpu = set ? i : -1;
+ i = 0;
+ for_each_online_cpu(cpu) {
virtqueue_set_affinity(vi->rq[i].vq, cpu);
virtqueue_set_affinity(vi->sq[i].vq, cpu);
+ *per_cpu_ptr(vi->vq_index, cpu) = i;
+ i++;
}
- if (set)
- vi->affinity_hint_set = true;
- else
- vi->affinity_hint_set = false;
+ vi->affinity_hint_set = true;
+}
+
+static int virtnet_cpu_callback(struct notifier_block *nfb,
+ unsigned long action, void *hcpu)
+{
+ struct virtnet_info *vi = container_of(nfb, struct virtnet_info, nb);
+
+ switch(action & ~CPU_TASKS_FROZEN) {
+ case CPU_ONLINE:
+ case CPU_DOWN_FAILED:
+ case CPU_DEAD:
+ virtnet_set_affinity(vi);
+ break;
+ case CPU_DOWN_PREPARE:
+ virtnet_clean_affinity(vi, (long)hcpu);
+ break;
+ default:
+ break;
+ }
+ return NOTIFY_OK;
}
static void virtnet_get_ringparam(struct net_device *dev,
if (queue_pairs > vi->max_queue_pairs)
return -EINVAL;
+ get_online_cpus();
err = virtnet_set_queues(vi, queue_pairs);
if (!err) {
netif_set_real_num_tx_queues(dev, queue_pairs);
netif_set_real_num_rx_queues(dev, queue_pairs);
- virtnet_set_affinity(vi, true);
+ virtnet_set_affinity(vi);
}
+ put_online_cpus();
return err;
}
/* To avoid contending a lock hold by a vcpu who would exit to host, select the
* txq based on the processor id.
- * TODO: handle cpu hotplug.
*/
static u16 virtnet_select_queue(struct net_device *dev, struct sk_buff *skb)
{
- int txq = skb_rx_queue_recorded(skb) ? skb_get_rx_queue(skb) :
- smp_processor_id();
+ int txq;
+ struct virtnet_info *vi = netdev_priv(dev);
+
+ if (skb_rx_queue_recorded(skb)) {
+ txq = skb_get_rx_queue(skb);
+ } else {
+ txq = *__this_cpu_ptr(vi->vq_index);
+ if (txq == -1)
+ txq = 0;
+ }
while (unlikely(txq >= dev->real_num_tx_queues))
txq -= dev->real_num_tx_queues;
{
struct virtio_device *vdev = vi->vdev;
- virtnet_set_affinity(vi, false);
+ virtnet_clean_affinity(vi, -1);
vdev->config->del_vqs(vdev);
if (ret)
goto err_free;
- virtnet_set_affinity(vi, true);
+ get_online_cpus();
+ virtnet_set_affinity(vi);
+ put_online_cpus();
+
return 0;
err_free:
if (vi->stats == NULL)
goto free;
+ vi->vq_index = alloc_percpu(int);
+ if (vi->vq_index == NULL)
+ goto free_stats;
+
mutex_init(&vi->config_lock);
vi->config_enable = true;
INIT_WORK(&vi->config_work, virtnet_config_changed_work);
/* Allocate/initialize the rx/tx queues, and invoke find_vqs */
err = init_vqs(vi);
if (err)
- goto free_stats;
+ goto free_index;
netif_set_real_num_tx_queues(dev, 1);
netif_set_real_num_rx_queues(dev, 1);
}
}
+ vi->nb.notifier_call = &virtnet_cpu_callback;
+ err = register_hotcpu_notifier(&vi->nb);
+ if (err) {
+ pr_debug("virtio_net: registering cpu notifier failed\n");
+ goto free_recv_bufs;
+ }
+
/* Assume link up if device can't report link status,
otherwise get link status from config. */
if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_STATUS)) {
free_vqs:
cancel_delayed_work_sync(&vi->refill);
virtnet_del_vqs(vi);
+free_index:
+ free_percpu(vi->vq_index);
free_stats:
free_percpu(vi->stats);
free:
{
struct virtnet_info *vi = vdev->priv;
+ unregister_hotcpu_notifier(&vi->nb);
+
/* Prevent config work handler from accessing the device. */
mutex_lock(&vi->config_lock);
vi->config_enable = false;
flush_work(&vi->config_work);
+ free_percpu(vi->vq_index);
free_percpu(vi->stats);
free_netdev(vi->dev);
}
projects / karo-tx-linux.git / blobdiff