|
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH RFC 4/4] xen-netfront: Add support for multiple queues
On Wed, Jan 15, 2014 at 04:23:24PM +0000, Andrew J. Bennieston wrote:
> From: "Andrew J. Bennieston" <andrew.bennieston@xxxxxxxxxx>
>
> Build on the refactoring of the previous patch to implement multiple
> queues between xen-netfront and xen-netback.
>
> Check XenStore for multi-queue support, and set up the rings and event
> channels accordingly.
>
> Write ring references and event channels to XenStore in a queue
> hierarchy if appropriate, or flat when using only one queue.
>
> Update the xennet_select_queue() function to choose the queue on which
> to transmit a packet based on the skb rxhash result.
>
> Signed-off-by: Andrew J. Bennieston <andrew.bennieston@xxxxxxxxxx>
> ---
> drivers/net/xen-netfront.c | 167
> ++++++++++++++++++++++++++++++++++----------
> 1 file changed, 130 insertions(+), 37 deletions(-)
>
> diff --git a/drivers/net/xen-netfront.c b/drivers/net/xen-netfront.c
> index 508ea96..9b08da5 100644
> --- a/drivers/net/xen-netfront.c
> +++ b/drivers/net/xen-netfront.c
> @@ -57,6 +57,10 @@
> #include <xen/interface/memory.h>
> #include <xen/interface/grant_table.h>
>
> +/* Module parameters */
> +unsigned int xennet_max_queues = 16;
Should this be based on some for of num_online_cpus() ?
> +module_param(xennet_max_queues, uint, 0644);
How about just 'max_queues' ? Without the 'xennet'?
> +
> static const struct ethtool_ops xennet_ethtool_ops;
>
> struct netfront_cb {
> @@ -556,8 +560,19 @@ static int xennet_count_skb_frag_slots(struct sk_buff
> *skb)
>
> static u16 xennet_select_queue(struct net_device *dev, struct sk_buff *skb)
> {
> - /* Stub for later implementation of queue selection */
> - return 0;
> + struct netfront_info *info = netdev_priv(dev);
> + u32 hash;
> + u16 queue_idx;
> +
> + /* First, check if there is only one queue */
> + if (info->num_queues == 1)
> + queue_idx = 0;
> + else {
> + hash = skb_get_rxhash(skb);
> + queue_idx = (u16) (((u64)hash * info->num_queues) >> 32);
> + }
> +
> + return queue_idx;
> }
>
> static int xennet_start_xmit(struct sk_buff *skb, struct net_device *dev)
> @@ -1361,7 +1376,7 @@ static struct net_device *xennet_create_dev(struct
> xenbus_device *dev)
> struct net_device *netdev;
> struct netfront_info *np;
>
> - netdev = alloc_etherdev_mq(sizeof(struct netfront_info), 1);
> + netdev = alloc_etherdev_mq(sizeof(struct netfront_info),
> xennet_max_queues);
> if (!netdev)
> return ERR_PTR(-ENOMEM);
>
> @@ -1731,6 +1746,89 @@ static int xennet_init_queue(struct netfront_queue
> *queue)
> return err;
> }
>
> +static int write_queue_xenstore_keys(struct netfront_queue *queue,
> + struct xenbus_transaction *xbt, int
> write_hierarchical)
> +{
> + /* Write the queue-specific keys into XenStore in the traditional
> + * way for a single queue, or in a queue subkeys for multiple
> + * queues.
> + */
> + struct xenbus_device *dev = queue->info->xbdev;
> + int err;
> + const char *message;
> + char *path;
> + size_t pathsize;
> +
> + /* Choose the correct place to write the keys */
> + if (write_hierarchical) {
> + pathsize = strlen(dev->nodename) + 10;
> + path = kzalloc(pathsize, GFP_KERNEL);
> + if (!path) {
> + err = -ENOMEM;
> + message = "writing ring references";
> + goto error;
> + }
> + snprintf(path, pathsize, "%s/queue-%u",
> + dev->nodename, queue->number);
> + }
> + else
> + path = (char *)dev->nodename;
> +
> + /* Write ring references */
> + err = xenbus_printf(*xbt, path, "tx-ring-ref", "%u",
> + queue->tx_ring_ref);
> + if (err) {
> + message = "writing tx-ring-ref";
> + goto error;
> + }
> +
> + err = xenbus_printf(*xbt, path, "rx-ring-ref", "%u",
> + queue->rx_ring_ref);
> + if (err) {
> + message = "writing rx-ring-ref";
> + goto error;
> + }
> +
> + /* Write event channels; taking into account both shared
> + * and split event channel scenarios.
> + */
> + if (queue->tx_evtchn == queue->rx_evtchn) {
> + /* Shared event channel */
> + err = xenbus_printf(*xbt, path,
> + "event-channel", "%u", queue->tx_evtchn);
> + if (err) {
> + message = "writing event-channel";
> + goto error;
> + }
> + }
> + else {
> + /* Split event channels */
> + err = xenbus_printf(*xbt, path,
> + "event-channel-tx", "%u", queue->tx_evtchn);
> + if (err) {
> + message = "writing event-channel-tx";
> + goto error;
> + }
> +
> + err = xenbus_printf(*xbt, path,
> + "event-channel-rx", "%u", queue->rx_evtchn);
> + if (err) {
> + message = "writing event-channel-rx";
> + goto error;
> + }
> + }
> +
> + if (write_hierarchical)
> + kfree(path);
> + return 0;
> +
> +error:
> + if (write_hierarchical)
> + kfree(path);
> + xenbus_dev_fatal(dev, err, "%s", message);
> + return err;
> +}
> +
> /* Common code used when first setting up, and when resuming. */
> static int talk_to_netback(struct xenbus_device *dev,
> struct netfront_info *info)
> @@ -1740,10 +1838,17 @@ static int talk_to_netback(struct xenbus_device *dev,
> int err;
> unsigned int feature_split_evtchn;
> unsigned int i = 0;
> + unsigned int max_queues = 0;
> struct netfront_queue *queue = NULL;
>
> info->netdev->irq = 0;
>
> + /* Check if backend supports multiple queues */
> + err = xenbus_scanf(XBT_NIL, info->xbdev->otherend,
> + "multi-queue-max-queues", "%u", &max_queues);
> + if (err < 0)
> + max_queues = 1;
> +
> /* Check feature-split-event-channels */
> err = xenbus_scanf(XBT_NIL, info->xbdev->otherend,
> "feature-split-event-channels", "%u",
> @@ -1759,12 +1864,12 @@ static int talk_to_netback(struct xenbus_device *dev,
> }
>
> /* Allocate array of queues */
> - info->queues = kcalloc(1, sizeof(struct netfront_queue), GFP_KERNEL);
> + info->queues = kcalloc(max_queues, sizeof(struct netfront_queue),
> GFP_KERNEL);
> if (!info->queues) {
> err = -ENOMEM;
> goto out;
> }
> - info->num_queues = 1;
> + info->num_queues = max_queues;
>
> /* Create shared ring, alloc event channel -- for each queue */
> for (i = 0; i < info->num_queues; ++i) {
> @@ -1800,49 +1905,36 @@ static int talk_to_netback(struct xenbus_device *dev,
> }
>
> again:
> - queue = &info->queues[0]; /* Use first queue only */
> -
> err = xenbus_transaction_start(&xbt);
> if (err) {
> xenbus_dev_fatal(dev, err, "starting transaction");
> goto destroy_ring;
> }
>
> - err = xenbus_printf(xbt, dev->nodename, "tx-ring-ref", "%u",
> - queue->tx_ring_ref);
> - if (err) {
> - message = "writing tx ring-ref";
> - goto abort_transaction;
> - }
> - err = xenbus_printf(xbt, dev->nodename, "rx-ring-ref", "%u",
> - queue->rx_ring_ref);
> - if (err) {
> - message = "writing rx ring-ref";
> - goto abort_transaction;
> + if (info->num_queues == 1) {
> + err = write_queue_xenstore_keys(&info->queues[0], &xbt, 0); /*
> flat */
> + if (err)
> + goto abort_transaction_no_dev_fatal;
> }
> -
> - if (queue->tx_evtchn == queue->rx_evtchn) {
> - err = xenbus_printf(xbt, dev->nodename,
> - "event-channel", "%u", queue->tx_evtchn);
> + else {
> + /* Write the number of queues */
> + err = xenbus_printf(xbt, dev->nodename,
> "multi-queue-num-queues",
> + "%u", info->num_queues);
> if (err) {
> - message = "writing event-channel";
> - goto abort_transaction;
> + message = "writing multi-queue-num-queues";
> + goto abort_transaction_no_dev_fatal;
> }
> - } else {
> - err = xenbus_printf(xbt, dev->nodename,
> - "event-channel-tx", "%u", queue->tx_evtchn);
> - if (err) {
> - message = "writing event-channel-tx";
> - goto abort_transaction;
> - }
> - err = xenbus_printf(xbt, dev->nodename,
> - "event-channel-rx", "%u", queue->rx_evtchn);
> - if (err) {
> - message = "writing event-channel-rx";
> - goto abort_transaction;
> +
> + /* Write the keys for each queue */
> + for (i = 0; i < info->num_queues; ++i) {
> + queue = &info->queues[i];
> + err = write_queue_xenstore_keys(queue, &xbt, 1); /*
> hierarchical */
> + if (err)
> + goto abort_transaction_no_dev_fatal;
> }
> }
>
> + /* The remaining keys are not queue-specific */
> err = xenbus_printf(xbt, dev->nodename, "request-rx-copy", "%u",
> 1);
> if (err) {
> @@ -1879,8 +1971,9 @@ again:
> return 0;
>
> abort_transaction:
> - xenbus_transaction_end(xbt, 1);
> xenbus_dev_fatal(dev, err, "%s", message);
> +abort_transaction_no_dev_fatal:
> + xenbus_transaction_end(xbt, 1);
> destroy_ring:
> xennet_disconnect_backend(info);
> kfree(info->queues);
> --
> 1.7.10.4
>
>
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@xxxxxxxxxxxxx
> http://lists.xen.org/xen-devel
_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
http://lists.xen.org/xen-devel
|
 |
Lists.xenproject.org is hosted with RackSpace, monitoring our |