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if_vtnet: Limit allocations of unused virtqueues

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For multiqueue, we may use fewer than the provided maximum number of
queues. Try to limit allocations of the unused queues: no interrupts,
no indirect descriptors, and no taskqueues.

Reviewed by: grehan (mentor)
Differential Revision: https://reviews.freebsd.org/D27921
This commit is contained in:
Bryan Venteicher 2021-01-19 04:55:25 +00:00
parent b470419ea5
commit bd8809df20
1 changed files with 27 additions and 13 deletions
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40
sys/dev/virtio/network/if_vtnet.c
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@ -758,6 +758,7 @@ vtnet_setup_features(struct vtnet_softc *sc)
else
sc->vtnet_tx_nsegs = VTNET_TX_SEGS_MIN;
sc->vtnet_req_vq_pairs = 1;
sc->vtnet_max_vq_pairs = 1;
if (virtio_with_feature(dev, VIRTIO_NET_F_CTRL_VQ)) {
@ -785,8 +786,10 @@ vtnet_setup_features(struct vtnet_softc *sc)
* number of CPUs and the configured maximum.
*/
req = vtnet_tunable_int(sc, "mq_max_pairs", vtnet_mq_max_pairs);
if (req < 1)
if (req < 0)
req = 1;
if (req == 0)
req = mp_ncpus;
if (req > sc->vtnet_max_vq_pairs)
req = sc->vtnet_max_vq_pairs;
if (req > mp_ncpus)
@ -1014,16 +1017,27 @@ vtnet_alloc_virtqueues(struct vtnet_softc *sc)
if (info == NULL)
return (ENOMEM);
for (i = 0, idx = 0; i < sc->vtnet_max_vq_pairs; i++, idx += 2) {
for (i = 0, idx = 0; i < sc->vtnet_req_vq_pairs; i++, idx += 2) {
rxq = &sc->vtnet_rxqs[i];
VQ_ALLOC_INFO_INIT(&info[idx], sc->vtnet_rx_nsegs,
vtnet_rx_vq_intr, rxq, &rxq->vtnrx_vq,
"%s-%d rx", device_get_nameunit(dev), rxq->vtnrx_id);
"%s-rx%d", device_get_nameunit(dev), rxq->vtnrx_id);
txq = &sc->vtnet_txqs[i];
VQ_ALLOC_INFO_INIT(&info[idx+1], sc->vtnet_tx_nsegs,
vtnet_tx_vq_intr, txq, &txq->vtntx_vq,
"%s-%d tx", device_get_nameunit(dev), txq->vtntx_id);
"%s-tx%d", device_get_nameunit(dev), txq->vtntx_id);
}
/* These queues will not be used so allocate the minimum resources. */
for (/**/; i < sc->vtnet_max_vq_pairs; i++, idx += 2) {
rxq = &sc->vtnet_rxqs[i];
VQ_ALLOC_INFO_INIT(&info[idx], 0, NULL, rxq, &rxq->vtnrx_vq,
"%s-rx%d", device_get_nameunit(dev), rxq->vtnrx_id);
txq = &sc->vtnet_txqs[i];
VQ_ALLOC_INFO_INIT(&info[idx+1], 0, NULL, txq, &txq->vtntx_vq,
"%s-tx%d", device_get_nameunit(dev), txq->vtntx_id);
}
if (sc->vtnet_flags & VTNET_FLAG_CTRL_VQ) {
@ -3006,7 +3020,7 @@ vtnet_start_taskqueues(struct vtnet_softc *sc)
* Most drivers just ignore the return value - it only fails
* with ENOMEM so an error is not likely.
*/
for (i = 0; i < sc->vtnet_max_vq_pairs; i++) {
for (i = 0; i < sc->vtnet_req_vq_pairs; i++) {
rxq = &sc->vtnet_rxqs[i];
error = taskqueue_start_threads(&rxq->vtnrx_tq, 1, PI_NET,
"%s rxq %d", device_get_nameunit(dev), rxq->vtnrx_id);
@ -3076,7 +3090,7 @@ vtnet_drain_rxtx_queues(struct vtnet_softc *sc)
struct vtnet_txq *txq;
int i;
for (i = 0; i < sc->vtnet_act_vq_pairs; i++) {
for (i = 0; i < sc->vtnet_max_vq_pairs; i++) {
rxq = &sc->vtnet_rxqs[i];
vtnet_rxq_free_mbufs(rxq);
@ -3289,8 +3303,8 @@ vtnet_set_active_vq_pairs(struct vtnet_softc *sc)
npairs = sc->vtnet_req_vq_pairs;
if (vtnet_ctrl_mq_cmd(sc, npairs) != 0) {
device_printf(dev,
"cannot set active queue pairs to %d\n", npairs);
device_printf(dev, "cannot set active queue pairs to %d, "
"falling back to 1 queue pair\n", npairs);
npairs = 1;
}
@ -4083,7 +4097,7 @@ vtnet_setup_queue_sysctl(struct vtnet_softc *sc)
tree = device_get_sysctl_tree(dev);
child = SYSCTL_CHILDREN(tree);
for (i = 0; i < sc->vtnet_max_vq_pairs; i++) {
for (i = 0; i < sc->vtnet_req_vq_pairs; i++) {
vtnet_setup_rxq_sysctl(ctx, child, &sc->vtnet_rxqs[i]);
vtnet_setup_txq_sysctl(ctx, child, &sc->vtnet_txqs[i]);
}
@ -4278,7 +4292,7 @@ vtnet_disable_rx_interrupts(struct vtnet_softc *sc)
{
int i;
for (i = 0; i < sc->vtnet_act_vq_pairs; i++)
for (i = 0; i < sc->vtnet_max_vq_pairs; i++)
vtnet_rxq_disable_intr(&sc->vtnet_rxqs[i]);
}
@ -4287,7 +4301,7 @@ vtnet_disable_tx_interrupts(struct vtnet_softc *sc)
{
int i;
for (i = 0; i < sc->vtnet_act_vq_pairs; i++)
for (i = 0; i < sc->vtnet_max_vq_pairs; i++)
vtnet_txq_disable_intr(&sc->vtnet_txqs[i]);
}
@ -4320,7 +4334,7 @@ vtnet_debugnet_init(struct ifnet *ifp, int *nrxr, int *ncl, int *clsize)
sc = if_getsoftc(ifp);
VTNET_CORE_LOCK(sc);
*nrxr = sc->vtnet_max_vq_pairs;
*nrxr = sc->vtnet_req_vq_pairs;
*ncl = DEBUGNET_MAX_IN_FLIGHT;
*clsize = sc->vtnet_rx_clustersz;
VTNET_CORE_UNLOCK(sc);
@ -4362,7 +4376,7 @@ vtnet_debugnet_poll(struct ifnet *ifp, int count)
return (EBUSY);
(void)vtnet_txq_eof(&sc->vtnet_txqs[0]);
for (i = 0; i < sc->vtnet_max_vq_pairs; i++)
for (i = 0; i < sc->vtnet_act_vq_pairs; i++)
(void)vtnet_rxq_eof(&sc->vtnet_rxqs[i]);
return (0);
}