diff options
| -rw-r--r-- | Documentation/networking/multiqueue.txt | 47 | ||||
| -rw-r--r-- | include/linux/pkt_sched.h | 7 | ||||
| -rw-r--r-- | net/sched/Kconfig | 9 | ||||
| -rw-r--r-- | net/sched/Makefile | 1 | ||||
| -rw-r--r-- | net/sched/sch_multiq.c | 467 |
5 files changed, 530 insertions, 1 deletions
diff --git a/Documentation/networking/multiqueue.txt b/Documentation/networking/multiqueue.txt index d391ea6..5787ee6 100644 --- a/Documentation/networking/multiqueue.txt +++ b/Documentation/networking/multiqueue.txt @@ -24,4 +24,49 @@ netif_{start|stop|wake}_subqueue() functions to manage each queue while the device is still operational. netdev->queue_lock is still used when the device comes online or when it's completely shut down (unregister_netdev(), etc.). -Author: Peter P. Waskiewicz Jr. <peter.p.waskiewicz.jr@intel.com> + +Section 2: Qdisc support for multiqueue devices + +----------------------------------------------- + +Currently two qdiscs support multiqueue devices. The first is the default +pfifo_fast qdisc. This qdisc supports one qdisc per hardware queue. A new +round-robin qdisc, sch_multiq also supports multiple hardware queues. The +qdisc is responsible for classifying the skb's and then directing the skb's to +bands and queues based on the value in skb->queue_mapping. Use this field in +the base driver to determine which queue to send the skb to. + +sch_multiq has been added for hardware that wishes to avoid unnecessary +requeuing. It will cycle though the bands and verify that the hardware queue +associated with the band is not stopped prior to dequeuing a packet. + +On qdisc load, the number of bands is based on the number of queues on the +hardware. Once the association is made, any skb with skb->queue_mapping set, +will be queued to the band associated with the hardware queue. + + +Section 3: Brief howto using MULTIQ for multiqueue devices +--------------------------------------------------------------- + +The userspace command 'tc,' part of the iproute2 package, is used to configure +qdiscs. To add the MULTIQ qdisc to your network device, assuming the device +is called eth0, run the following command: + +# tc qdisc add dev eth0 root handle 1: multiq + +The qdisc will allocate the number of bands to equal the number of queues that +the device reports, and bring the qdisc online. Assuming eth0 has 4 Tx +queues, the band mapping would look like: + +band 0 => queue 0 +band 1 => queue 1 +band 2 => queue 2 +band 3 => queue 3 + +Traffic will begin flowing through each queue if your base device has either +the default simple_tx_hash or a custom netdev->select_queue() defined. + +The behavior of tc filters remains the same. + +Author: Alexander Duyck <alexander.h.duyck@intel.com> +Original Author: Peter P. Waskiewicz Jr. <peter.p.waskiewicz.jr@intel.com> diff --git a/include/linux/pkt_sched.h b/include/linux/pkt_sched.h index e5de421..5d921fa 100644 --- a/include/linux/pkt_sched.h +++ b/include/linux/pkt_sched.h @@ -123,6 +123,13 @@ struct tc_prio_qopt __u8 priomap[TC_PRIO_MAX+1]; /* Map: logical priority -> PRIO band */ }; +/* MULTIQ section */ + +struct tc_multiq_qopt { + __u16 bands; /* Number of bands */ + __u16 max_bands; /* Maximum number of queues */ +}; + /* TBF section */ struct tc_tbf_qopt diff --git a/net/sched/Kconfig b/net/sched/Kconfig index 9437b27..efaa7a7 100644 --- a/net/sched/Kconfig +++ b/net/sched/Kconfig @@ -106,6 +106,15 @@ config NET_SCH_PRIO To compile this code as a module, choose M here: the module will be called sch_prio. +config NET_SCH_MULTIQ + tristate "Hardware Multiqueue-aware Multi Band Queuing (MULTIQ)" + ---help--- + Say Y here if you want to use an n-band queue packet scheduler + to support devices that have multiple hardware transmit queues. + + To compile this code as a module, choose M here: the + module will be called sch_multiq. + config NET_SCH_RED tristate "Random Early Detection (RED)" ---help--- diff --git a/net/sched/Makefile b/net/sched/Makefile index 1d2b0f7..3d9b953 100644 --- a/net/sched/Makefile +++ b/net/sched/Makefile @@ -26,6 +26,7 @@ obj-$(CONFIG_NET_SCH_SFQ) += sch_sfq.o obj-$(CONFIG_NET_SCH_TBF) += sch_tbf.o obj-$(CONFIG_NET_SCH_TEQL) += sch_teql.o obj-$(CONFIG_NET_SCH_PRIO) += sch_prio.o +obj-$(CONFIG_NET_SCH_MULTIQ) += sch_multiq.o obj-$(CONFIG_NET_SCH_ATM) += sch_atm.o obj-$(CONFIG_NET_SCH_NETEM) += sch_netem.o obj-$(CONFIG_NET_CLS_U32) += cls_u32.o diff --git a/net/sched/sch_multiq.c b/net/sched/sch_multiq.c new file mode 100644 index 0000000..49a8b67 --- /dev/null +++ b/net/sched/sch_multiq.c @@ -0,0 +1,467 @@ +/* + * Copyright (c) 2008, Intel Corporation. + * + * This program is free software; you can redistribute it and/or modify it + * under the terms and conditions of the GNU General Public License, + * version 2, as published by the Free Software Foundation. + * + * This program is distributed in the hope it will be useful, but WITHOUT + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for + * more details. + * + * You should have received a copy of the GNU General Public License along with + * this program; if not, write to the Free Software Foundation, Inc., 59 Temple + * Place - Suite 330, Boston, MA 02111-1307 USA. + * + * Author: Alexander Duyck <alexander.h.duyck@intel.com> + */ + +#include <linux/module.h> +#include <linux/types.h> +#include <linux/kernel.h> +#include <linux/string.h> +#include <linux/errno.h> +#include <linux/skbuff.h> +#include <net/netlink.h> +#include <net/pkt_sched.h> + + +struct multiq_sched_data { + u16 bands; + u16 max_bands; + u16 curband; + struct tcf_proto *filter_list; + struct Qdisc **queues; +}; + + +static struct Qdisc * +multiq_classify(struct sk_buff *skb, struct Qdisc *sch, int *qerr) +{ + struct multiq_sched_data *q = qdisc_priv(sch); + u32 band; + struct tcf_result res; + int err; + + *qerr = NET_XMIT_SUCCESS | __NET_XMIT_BYPASS; + err = tc_classify(skb, q->filter_list, &res); +#ifdef CONFIG_NET_CLS_ACT + switch (err) { + case TC_ACT_STOLEN: + case TC_ACT_QUEUED: + *qerr = NET_XMIT_SUCCESS | __NET_XMIT_STOLEN; + case TC_ACT_SHOT: + return NULL; + } +#endif + band = skb_get_queue_mapping(skb); + + if (band >= q->bands) + return q->queues[0]; + + return q->queues[band]; +} + +static int +multiq_enqueue(struct sk_buff *skb, struct Qdisc *sch) +{ + struct Qdisc *qdisc; + int ret; + + qdisc = multiq_classify(skb, sch, &ret); +#ifdef CONFIG_NET_CLS_ACT + if (qdisc == NULL) { + + if (ret & __NET_XMIT_BYPASS) + sch->qstats.drops++; + kfree_skb(skb); + return ret; + } +#endif + + ret = qdisc_enqueue(skb, qdisc); + if (ret == NET_XMIT_SUCCESS) { + sch->bstats.bytes += qdisc_pkt_len(skb); + sch->bstats.packets++; + sch->q.qlen++; + return NET_XMIT_SUCCESS; + } + if (net_xmit_drop_count(ret)) + sch->qstats.drops++; + return ret; +} + + +static int +multiq_requeue(struct sk_buff *skb, struct Qdisc *sch) +{ + struct Qdisc *qdisc; + int ret; + + qdisc = multiq_classify(skb, sch, &ret); +#ifdef CONFIG_NET_CLS_ACT + if (qdisc == NULL) { + if (ret & __NET_XMIT_BYPASS) + sch->qstats.drops++; + kfree_skb(skb); + return ret; + } +#endif + + ret = qdisc->ops->requeue(skb, qdisc); + if (ret == NET_XMIT_SUCCESS) { + sch->q.qlen++; + sch->qstats.requeues++; + return NET_XMIT_SUCCESS; + } + if (net_xmit_drop_count(ret)) + sch->qstats.drops++; + return ret; +} + + +static struct sk_buff *multiq_dequeue(struct Qdisc *sch) +{ + struct multiq_sched_data *q = qdisc_priv(sch); + struct Qdisc *qdisc; + struct sk_buff *skb; + int band; + + for (band = 0; band < q->bands; band++) { + /* cycle through bands to ensure fairness */ + q->curband++; + if (q->curband >= q->bands) + q->curband = 0; + + /* Check that target subqueue is available before + * pulling an skb to avoid excessive requeues + */ + if (!__netif_subqueue_stopped(qdisc_dev(sch), q->curband)) { + qdisc = q->queues[q->curband]; + skb = qdisc->dequeue(qdisc); + if (skb) { + sch->q.qlen--; + return skb; + } + } + } + return NULL; + +} + +static unsigned int multiq_drop(struct Qdisc *sch) +{ + struct multiq_sched_data *q = qdisc_priv(sch); + int band; + unsigned int len; + struct Qdisc *qdisc; + + for (band = q->bands-1; band >= 0; band--) { + qdisc = q->queues[band]; + if (qdisc->ops->drop) { + len = qdisc->ops->drop(qdisc); + if (len != 0) { + sch->q.qlen--; + return len; + } + } + } + return 0; +} + + +static void +multiq_reset(struct Qdisc *sch) +{ + u16 band; + struct multiq_sched_data *q = qdisc_priv(sch); + + for (band = 0; band < q->bands; band++) + qdisc_reset(q->queues[band]); + sch->q.qlen = 0; + q->curband = 0; +} + +static void +multiq_destroy(struct Qdisc *sch) +{ + int band; + struct multiq_sched_data *q = qdisc_priv(sch); + + tcf_destroy_chain(&q->filter_list); + for (band = 0; band < q->bands; band++) + qdisc_destroy(q->queues[band]); + + kfree(q->queues); +} + +static int multiq_tune(struct Qdisc *sch, struct nlattr *opt) +{ + struct multiq_sched_data *q = qdisc_priv(sch); + struct tc_multiq_qopt *qopt; + int i; + + if (!netif_is_multiqueue(qdisc_dev(sch))) + return -EINVAL; + if (nla_len(opt) < sizeof(*qopt)) + return -EINVAL; + + qopt = nla_data(opt); + + qopt->bands = qdisc_dev(sch)->real_num_tx_queues; + + sch_tree_lock(sch); + q->bands = qopt->bands; + for (i = q->bands; i < q->max_bands; i++) { + struct Qdisc *child = xchg(&q->queues[i], &noop_qdisc); + if (child != &noop_qdisc) { + qdisc_tree_decrease_qlen(child, child->q.qlen); + qdisc_destroy(child); + } + } + + sch_tree_unlock(sch); + + for (i = 0; i < q->bands; i++) { + if (q->queues[i] == &noop_qdisc) { + struct Qdisc *child; + child = qdisc_create_dflt(qdisc_dev(sch), + sch->dev_queue, + &pfifo_qdisc_ops, + TC_H_MAKE(sch->handle, + i + 1)); + if (child) { + sch_tree_lock(sch); + child = xchg(&q->queues[i], child); + + if (child != &noop_qdisc) { + qdisc_tree_decrease_qlen(child, + child->q.qlen); + qdisc_destroy(child); + } + sch_tree_unlock(sch); + } + } + } + return 0; +} + +static int multiq_init(struct Qdisc *sch, struct nlattr *opt) +{ + struct multiq_sched_data *q = qdisc_priv(sch); + int i; + + q->queues = NULL; + + if (opt == NULL) + return -EINVAL; + + q->max_bands = qdisc_dev(sch)->num_tx_queues; + + q->queues = kcalloc(q->max_bands, sizeof(struct Qdisc *), GFP_KERNEL); + if (!q->queues) + return -ENOBUFS; + for (i = 0; i < q->max_bands; i++) + q->queues[i] = &noop_qdisc; + + return multiq_tune(sch, opt); +} + +static int multiq_dump(struct Qdisc *sch, struct sk_buff *skb) +{ + struct multiq_sched_data *q = qdisc_priv(sch); + unsigned char *b = skb_tail_pointer(skb); + struct tc_multiq_qopt opt; + + opt.bands = q->bands; + opt.max_bands = q->max_bands; + + NLA_PUT(skb, TCA_OPTIONS, sizeof(opt), &opt); + + return skb->len; + +nla_put_failure: + nlmsg_trim(skb, b); + return -1; +} + +static int multiq_graft(struct Qdisc *sch, unsigned long arg, struct Qdisc *new, + struct Qdisc **old) +{ + struct multiq_sched_data *q = qdisc_priv(sch); + unsigned long band = arg - 1; + + if (band >= q->bands) + return -EINVAL; + + if (new == NULL) + new = &noop_qdisc; + + sch_tree_lock(sch); + *old = q->queues[band]; + q->queues[band] = new; + qdisc_tree_decrease_qlen(*old, (*old)->q.qlen); + qdisc_reset(*old); + sch_tree_unlock(sch); + + return 0; +} + +static struct Qdisc * +multiq_leaf(struct Qdisc *sch, unsigned long arg) +{ + struct multiq_sched_data *q = qdisc_priv(sch); + unsigned long band = arg - 1; + + if (band >= q->bands) + return NULL; + + return q->queues[band]; +} + +static unsigned long multiq_get(struct Qdisc *sch, u32 classid) +{ + struct multiq_sched_data *q = qdisc_priv(sch); + unsigned long band = TC_H_MIN(classid); + + if (band - 1 >= q->bands) + return 0; + return band; +} + +static unsigned long multiq_bind(struct Qdisc *sch, unsigned long parent, + u32 classid) +{ + return multiq_get(sch, classid); +} + + +static void multiq_put(struct Qdisc *q, unsigned long cl) +{ + return; +} + +static int multiq_change(struct Qdisc *sch, u32 handle, u32 parent, + struct nlattr **tca, unsigned long *arg) +{ + unsigned long cl = *arg; + struct multiq_sched_data *q = qdisc_priv(sch); + + if (cl - 1 > q->bands) + return -ENOENT; + return 0; +} + +static int multiq_delete(struct Qdisc *sch, unsigned long cl) +{ + struct multiq_sched_data *q = qdisc_priv(sch); + if (cl - 1 > q->bands) + return -ENOENT; + return 0; +} + + +static int multiq_dump_class(struct Qdisc *sch, unsigned long cl, + struct sk_buff *skb, struct tcmsg *tcm) +{ + struct multiq_sched_data *q = qdisc_priv(sch); + + if (cl - 1 > q->bands) + return -ENOENT; + tcm->tcm_handle |= TC_H_MIN(cl); + if (q->queues[cl-1]) + tcm->tcm_info = q->queues[cl-1]->handle; + return 0; +} + +static int multiq_dump_class_stats(struct Qdisc *sch, unsigned long cl, + struct gnet_dump *d) +{ + struct multiq_sched_data *q = qdisc_priv(sch); + struct Qdisc *cl_q; + + cl_q = q->queues[cl - 1]; + if (gnet_stats_copy_basic(d, &cl_q->bstats) < 0 || + gnet_stats_copy_queue(d, &cl_q->qstats) < 0) + return -1; + + return 0; +} + +static void multiq_walk(struct Qdisc *sch, struct qdisc_walker *arg) +{ + struct multiq_sched_data *q = qdisc_priv(sch); + int band; + + if (arg->stop) + return; + + for (band = 0; band < q->bands; band++) { + if (arg->count < arg->skip) { + arg->count++; + continue; + } + if (arg->fn(sch, band+1, arg) < 0) { + arg->stop = 1; + break; + } + arg->count++; + } +} + +static struct tcf_proto **multiq_find_tcf(struct Qdisc *sch, unsigned long cl) +{ + struct multiq_sched_data *q = qdisc_priv(sch); + + if (cl) + return NULL; + return &q->filter_list; +} + +static const struct Qdisc_class_ops multiq_class_ops = { + .graft = multiq_graft, + .leaf = multiq_leaf, + .get = multiq_get, + .put = multiq_put, + .change = multiq_change, + .delete = multiq_delete, + .walk = multiq_walk, + .tcf_chain = multiq_find_tcf, + .bind_tcf = multiq_bind, + .unbind_tcf = multiq_put, + .dump = multiq_dump_class, + .dump_stats = multiq_dump_class_stats, +}; + +static struct Qdisc_ops multiq_qdisc_ops __read_mostly = { + .next = NULL, + .cl_ops = &multiq_class_ops, + .id = "multiq", + .priv_size = sizeof(struct multiq_sched_data), + .enqueue = multiq_enqueue, + .dequeue = multiq_dequeue, + .requeue = multiq_requeue, + .drop = multiq_drop, + .init = multiq_init, + .reset = multiq_reset, + .destroy = multiq_destroy, + .change = multiq_tune, + .dump = multiq_dump, + .owner = THIS_MODULE, +}; + +static int __init multiq_module_init(void) +{ + return register_qdisc(&multiq_qdisc_ops); +} + +static void __exit multiq_module_exit(void) +{ + unregister_qdisc(&multiq_qdisc_ops); +} + +module_init(multiq_module_init) +module_exit(multiq_module_exit) + +MODULE_LICENSE("GPL"); |