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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH RFC 2/4] xen-netback: Add support for multiple queues
> -----Original Message----- > From: Andrew J. Bennieston [mailto:andrew.bennieston@xxxxxxxxxx] > Sent: 15 January 2014 16:23 > To: xen-devel@xxxxxxxxxxxxxxxxxxxx > Cc: Ian Campbell; Wei Liu; Paul Durrant; Andrew Bennieston > Subject: [PATCH RFC 2/4] xen-netback: Add support for multiple queues > > From: "Andrew J. Bennieston" <andrew.bennieston@xxxxxxxxxx> > > Builds on the refactoring of the previous patch to implement multiple > queues between xen-netfront and xen-netback. > > Writes the maximum supported number of queues into XenStore, and reads > the values written by the frontend to determine how many queues to use. > > Ring references and event channels are read from XenStore on a per-queue > basis and rings are connected accordingly. > > Signed-off-by: Andrew J. Bennieston <andrew.bennieston@xxxxxxxxxx> > --- > drivers/net/xen-netback/common.h | 2 + > drivers/net/xen-netback/interface.c | 8 +++- > drivers/net/xen-netback/netback.c | 3 ++ > drivers/net/xen-netback/xenbus.c | 70 > ++++++++++++++++++++++++++++++----- > 4 files changed, 72 insertions(+), 11 deletions(-) > > diff --git a/drivers/net/xen-netback/common.h b/drivers/net/xen- > netback/common.h > index 54d2eeb..97efd09 100644 > --- a/drivers/net/xen-netback/common.h > +++ b/drivers/net/xen-netback/common.h > @@ -254,4 +254,6 @@ void xenvif_carrier_on(struct xenvif *vif); > > extern bool separate_tx_rx_irq; > > +extern unsigned int xenvif_max_queues; > + > #endif /* __XEN_NETBACK__COMMON_H__ */ > diff --git a/drivers/net/xen-netback/interface.c b/drivers/net/xen- > netback/interface.c > index 0113324..0234ff0 100644 > --- a/drivers/net/xen-netback/interface.c > +++ b/drivers/net/xen-netback/interface.c > @@ -355,7 +355,13 @@ struct xenvif *xenvif_alloc(struct device *parent, > domid_t domid, > char name[IFNAMSIZ] = {}; > > snprintf(name, IFNAMSIZ - 1, "vif%u.%u", domid, handle); > - dev = alloc_netdev_mq(sizeof(struct xenvif), name, ether_setup, 1); > + /* > + * Allocate a netdev with the max. supported number of queues. > + * When the guest selects the desired number, it will be updated > + * via netif_set_real_num_tx_queues(). > + */ > + dev = alloc_netdev_mq(sizeof(struct xenvif), name, ether_setup, > + xenvif_max_queues); > if (dev == NULL) { > pr_warn("Could not allocate netdev for %s\n", name); > return ERR_PTR(-ENOMEM); > diff --git a/drivers/net/xen-netback/netback.c b/drivers/net/xen- > netback/netback.c > index 586e741..5d717d7 100644 > --- a/drivers/net/xen-netback/netback.c > +++ b/drivers/net/xen-netback/netback.c > @@ -55,6 +55,9 @@ > bool separate_tx_rx_irq = 1; > module_param(separate_tx_rx_irq, bool, 0644); > > +unsigned int xenvif_max_queues = 4; > +module_param(xenvif_max_queues, uint, 0644); > + > /* > * This is the maximum slots a skb can have. If a guest sends a skb > * which exceeds this limit it is considered malicious. > diff --git a/drivers/net/xen-netback/xenbus.c b/drivers/net/xen- > netback/xenbus.c > index c3332e2..ce7ca9a 100644 > --- a/drivers/net/xen-netback/xenbus.c > +++ b/drivers/net/xen-netback/xenbus.c > @@ -21,6 +21,7 @@ > > #include "common.h" > #include <linux/vmalloc.h> > +#include <linux/rtnetlink.h> > > struct backend_info { > struct xenbus_device *dev; > @@ -160,6 +161,14 @@ static int netback_probe(struct xenbus_device *dev, > if (err) > pr_debug("Error writing feature-split-event-channels\n"); > > + /* > + * Multi-queue support: This is an optional feature. > + */ Comment style. Did you run checkpatch? > + err = xenbus_printf(XBT_NIL, dev->nodename, > + "multi-queue-max-queues", "%u", > xenvif_max_queues); > + if (err) > + pr_debug("Error writing multi-queue-max-queues\n"); > + > err = xenbus_switch_state(dev, XenbusStateInitWait); > if (err) > goto fail; > @@ -491,6 +500,16 @@ static void connect(struct backend_info *be) > unsigned long credit_bytes, credit_usec; > unsigned int queue_index; > struct xenvif_queue *queue; > + unsigned int requested_num_queues; > + > + /* Check whether the frontend requested multiple queues > + * and read the number requested. > + */ > + err = xenbus_scanf(XBT_NIL, dev->otherend, > + "multi-queue-num-queues", > + "%u", &requested_num_queues); > + if (err < 0) > + requested_num_queues = 1; /* Fall back to single queue */ > > err = xen_net_read_mac(dev, be->vif->fe_dev_addr); > if (err) { > @@ -501,9 +520,13 @@ static void connect(struct backend_info *be) > xen_net_read_rate(dev, &credit_bytes, &credit_usec); > read_xenbus_vif_flags(be); > > - be->vif->num_queues = 1; > + /* Use the number of queues requested by the frontend */ > + be->vif->num_queues = requested_num_queues; > be->vif->queues = vzalloc(be->vif->num_queues * > sizeof(struct xenvif_queue)); > + rtnl_lock(); > + netif_set_real_num_tx_queues(be->vif->dev, be->vif- > >num_queues); > + rtnl_unlock(); > > for (queue_index = 0; queue_index < be->vif->num_queues; > ++queue_index) > { > @@ -549,29 +572,51 @@ static int connect_rings(struct backend_info *be, > struct xenvif_queue *queue) > unsigned long tx_ring_ref, rx_ring_ref; > unsigned int tx_evtchn, rx_evtchn; > int err; > + char *xspath = NULL; > + size_t xspathsize; > + > + /* If the frontend requested 1 queue, or we have fallen back > + * to single queue due to lack of frontend support for multi- > + * queue, expect the remaining XenStore keys in the toplevel > + * directory. Otherwise, expect them in a subdirectory called > + * queue-N. > + */ > + if (queue->vif->num_queues == 1) > + xspath = (char *)dev->otherend; > + else { > + xspathsize = strlen(dev->otherend) + 10; Magic number. Paul > + xspath = kzalloc(xspathsize, GFP_KERNEL); > + if (!xspath) { > + xenbus_dev_fatal(dev, -ENOMEM, > + "reading ring references"); > + return -ENOMEM; > + } > + snprintf(xspath, xspathsize, "%s/queue-%u", dev- > >otherend, > + queue->number); > + } > > - err = xenbus_gather(XBT_NIL, dev->otherend, > + err = xenbus_gather(XBT_NIL, xspath, > "tx-ring-ref", "%lu", &tx_ring_ref, > "rx-ring-ref", "%lu", &rx_ring_ref, NULL); > if (err) { > xenbus_dev_fatal(dev, err, > "reading %s/ring-ref", > - dev->otherend); > - return err; > + xspath); > + goto err; > } > > /* Try split event channels first, then single event channel. */ > - err = xenbus_gather(XBT_NIL, dev->otherend, > + err = xenbus_gather(XBT_NIL, xspath, > "event-channel-tx", "%u", &tx_evtchn, > "event-channel-rx", "%u", &rx_evtchn, NULL); > if (err < 0) { > - err = xenbus_scanf(XBT_NIL, dev->otherend, > + err = xenbus_scanf(XBT_NIL, xspath, > "event-channel", "%u", &tx_evtchn); > if (err < 0) { > xenbus_dev_fatal(dev, err, > "reading %s/event-channel(-tx/rx)", > - dev->otherend); > - return err; > + xspath); > + goto err; > } > rx_evtchn = tx_evtchn; > } > @@ -584,10 +629,15 @@ static int connect_rings(struct backend_info *be, > struct xenvif_queue *queue) > "mapping shared-frames %lu/%lu port tx %u > rx %u", > tx_ring_ref, rx_ring_ref, > tx_evtchn, rx_evtchn); > - return err; > + goto err; > } > > - return 0; > + err = 0; > +err: /* Regular return falls through with err == 0 */ > + if (xspath != dev->otherend) > + kfree(xspath); > + > + return err; > } > > static int read_xenbus_vif_flags(struct backend_info *be) > -- > 1.7.10.4 _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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