* [net-next v7 1/2] net: sched: use queue_mapping to pick tx queue
2021-12-24 16:49 [net-next v7 0/2] net: sched: allow user to select txqueue xiangxia.m.yue
@ 2021-12-24 16:49 ` xiangxia.m.yue
2021-12-24 16:49 ` [net-next v7 2/2] net: sched: support hash/classid/cpuid selecting " xiangxia.m.yue
1 sibling, 0 replies; 7+ messages in thread
From: xiangxia.m.yue @ 2021-12-24 16:49 UTC (permalink / raw)
To: netdev
Cc: Tonghao Zhang, Jamal Hadi Salim, Cong Wang, Jiri Pirko,
David S. Miller, Jakub Kicinski, Jonathan Lemon, Eric Dumazet,
Alexander Lobakin, Paolo Abeni, Talal Ahmad, Kevin Hao,
Ilias Apalodimas, Kees Cook, Kumar Kartikeya Dwivedi,
Antoine Tenart, Wei Wang, Arnd Bergmann
From: Tonghao Zhang <xiangxia.m.yue@gmail.com>
This patch fixes issue:
* If we install tc filters with act_skbedit in clsact hook.
It doesn't work, because netdev_core_pick_tx() overwrites
queue_mapping.
$ tc filter ... action skbedit queue_mapping 1
And this patch is useful:
* We can use FQ + EDT to implement efficient policies. Tx queues
are picked by xps, ndo_select_queue of netdev driver, or skb hash
in netdev_core_pick_tx(). In fact, the netdev driver, and skb
hash are _not_ under control. xps uses the CPUs map to select Tx
queues, but we can't figure out which task_struct of pod/containter
running on this cpu in most case. We can use clsact filters to classify
one pod/container traffic to one Tx queue. Why ?
In containter networking environment, there are two kinds of pod/
containter/net-namespace. One kind (e.g. P1, P2), the high throughput
is key in these applications. But avoid running out of network resource,
the outbound traffic of these pods is limited, using or sharing one
dedicated Tx queues assigned HTB/TBF/FQ Qdisc. Other kind of pods
(e.g. Pn), the low latency of data access is key. And the traffic is not
limited. Pods use or share other dedicated Tx queues assigned FIFO Qdisc.
This choice provides two benefits. First, contention on the HTB/FQ Qdisc
lock is significantly reduced since fewer CPUs contend for the same queue.
More importantly, Qdisc contention can be eliminated completely if each
CPU has its own FIFO Qdisc for the second kind of pods.
There must be a mechanism in place to support classifying traffic based on
pods/container to different Tx queues. Note that clsact is outside of Qdisc
while Qdisc can run a classifier to select a sub-queue under the lock.
In general recording the decision in the skb seems a little heavy handed.
This patch introduces a per-CPU variable, suggested by Eric.
The xmit.skip_txqueue flag is firstly cleared in __dev_queue_xmit().
- Tx Qdisc may install that skbedit actions, then xmit.skip_txqueue flag
is set in qdisc->enqueue() though tx queue has been selected in
netdev_tx_queue_mapping() or netdev_core_pick_tx(). That flag is cleared
firstly in __dev_queue_xmit(), is useful:
- Avoid picking Tx queue with netdev_tx_queue_mapping() in next netdev
in such case: eth0 macvlan - eth0.3 vlan - eth0 ixgbe-phy:
For example, eth0, macvlan in pod, which root Qdisc install skbedit
queue_mapping, send packets to eth0.3, vlan in host. In __dev_queue_xmit() of
eth0.3, clear the flag, does not select tx queue according to skb->queue_mapping
because there is no filters in clsact or tx Qdisc of this netdev.
Same action taked in eth0, ixgbe in Host.
- Avoid picking Tx queue for next packet. If we set xmit.skip_txqueue
in tx Qdisc (qdisc->enqueue()), the proper way to clear it is clearing it
in __dev_queue_xmit when processing next packets.
For performance reasons, use the static key. If user does not config the NET_EGRESS,
the patch will not be compiled.
+----+ +----+ +----+
| P1 | | P2 | | Pn |
+----+ +----+ +----+
| | |
+-----------+-----------+
|
| clsact/skbedit
| MQ
v
+-----------+-----------+
| q0 | q1 | qn
v v v
HTB/FQ HTB/FQ ... FIFO
Cc: Jamal Hadi Salim <jhs@mojatatu.com>
Cc: Cong Wang <xiyou.wangcong@gmail.com>
Cc: Jiri Pirko <jiri@resnulli.us>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: Jonathan Lemon <jonathan.lemon@gmail.com>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Alexander Lobakin <alobakin@pm.me>
Cc: Paolo Abeni <pabeni@redhat.com>
Cc: Talal Ahmad <talalahmad@google.com>
Cc: Kevin Hao <haokexin@gmail.com>
Cc: Ilias Apalodimas <ilias.apalodimas@linaro.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Cc: Antoine Tenart <atenart@kernel.org>
Cc: Wei Wang <weiwan@google.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Suggested-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Tonghao Zhang <xiangxia.m.yue@gmail.com>
---
include/linux/netdevice.h | 3 +++
include/linux/rtnetlink.h | 1 +
net/core/dev.c | 31 +++++++++++++++++++++++++++++--
net/sched/act_skbedit.c | 6 +++++-
4 files changed, 38 insertions(+), 3 deletions(-)
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 8b0bdeb4734e..708e9f4cca01 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -3010,6 +3010,9 @@ struct softnet_data {
struct {
u16 recursion;
u8 more;
+#ifdef CONFIG_NET_EGRESS
+ u8 skip_txqueue;
+#endif
} xmit;
#ifdef CONFIG_RPS
/* input_queue_head should be written by cpu owning this struct,
diff --git a/include/linux/rtnetlink.h b/include/linux/rtnetlink.h
index bb9cb84114c1..e87c2dccc4d5 100644
--- a/include/linux/rtnetlink.h
+++ b/include/linux/rtnetlink.h
@@ -100,6 +100,7 @@ void net_dec_ingress_queue(void);
#ifdef CONFIG_NET_EGRESS
void net_inc_egress_queue(void);
void net_dec_egress_queue(void);
+void netdev_xmit_skip_txqueue(bool skip);
#endif
void rtnetlink_init(void);
diff --git a/net/core/dev.c b/net/core/dev.c
index a855e41bbe39..f66648d11a47 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -3860,6 +3860,25 @@ sch_handle_egress(struct sk_buff *skb, int *ret, struct net_device *dev)
return skb;
}
+
+static inline struct netdev_queue *
+netdev_tx_queue_mapping(struct net_device *dev, struct sk_buff *skb)
+{
+ int qm = skb_get_queue_mapping(skb);
+
+ return netdev_get_tx_queue(dev, netdev_cap_txqueue(dev, qm));
+}
+
+static inline bool netdev_xmit_txqueue_skipped(void)
+{
+ return __this_cpu_read(softnet_data.xmit.skip_txqueue);
+}
+
+void netdev_xmit_skip_txqueue(bool skip)
+{
+ __this_cpu_write(softnet_data.xmit.skip_txqueue, skip);
+}
+EXPORT_SYMBOL_GPL(netdev_xmit_skip_txqueue);
#endif /* CONFIG_NET_EGRESS */
#ifdef CONFIG_XPS
@@ -4030,7 +4049,7 @@ struct netdev_queue *netdev_core_pick_tx(struct net_device *dev,
static int __dev_queue_xmit(struct sk_buff *skb, struct net_device *sb_dev)
{
struct net_device *dev = skb->dev;
- struct netdev_queue *txq;
+ struct netdev_queue *txq = NULL;
struct Qdisc *q;
int rc = -ENOMEM;
bool again = false;
@@ -4058,11 +4077,17 @@ static int __dev_queue_xmit(struct sk_buff *skb, struct net_device *sb_dev)
if (!skb)
goto out;
}
+
+ netdev_xmit_skip_txqueue(false);
+
nf_skip_egress(skb, true);
skb = sch_handle_egress(skb, &rc, dev);
if (!skb)
goto out;
nf_skip_egress(skb, false);
+
+ if (netdev_xmit_txqueue_skipped())
+ txq = netdev_tx_queue_mapping(dev, skb);
}
#endif
/* If device/qdisc don't need skb->dst, release it right now while
@@ -4073,7 +4098,9 @@ static int __dev_queue_xmit(struct sk_buff *skb, struct net_device *sb_dev)
else
skb_dst_force(skb);
- txq = netdev_core_pick_tx(dev, skb, sb_dev);
+ if (likely(!txq))
+ txq = netdev_core_pick_tx(dev, skb, sb_dev);
+
q = rcu_dereference_bh(txq->qdisc);
trace_net_dev_queue(skb);
diff --git a/net/sched/act_skbedit.c b/net/sched/act_skbedit.c
index ceba11b198bb..d5799b4fc499 100644
--- a/net/sched/act_skbedit.c
+++ b/net/sched/act_skbedit.c
@@ -58,8 +58,12 @@ static int tcf_skbedit_act(struct sk_buff *skb, const struct tc_action *a,
}
}
if (params->flags & SKBEDIT_F_QUEUE_MAPPING &&
- skb->dev->real_num_tx_queues > params->queue_mapping)
+ skb->dev->real_num_tx_queues > params->queue_mapping) {
+#ifdef CONFIG_NET_EGRESS
+ netdev_xmit_skip_txqueue(true);
+#endif
skb_set_queue_mapping(skb, params->queue_mapping);
+ }
if (params->flags & SKBEDIT_F_MARK) {
skb->mark &= ~params->mask;
skb->mark |= params->mark & params->mask;
--
2.27.0
^ permalink raw reply related [flat|nested] 7+ messages in thread
* [net-next v7 2/2] net: sched: support hash/classid/cpuid selecting tx queue
2021-12-24 16:49 [net-next v7 0/2] net: sched: allow user to select txqueue xiangxia.m.yue
2021-12-24 16:49 ` [net-next v7 1/2] net: sched: use queue_mapping to pick tx queue xiangxia.m.yue
@ 2021-12-24 16:49 ` xiangxia.m.yue
2021-12-24 19:28 ` Cong Wang
1 sibling, 1 reply; 7+ messages in thread
From: xiangxia.m.yue @ 2021-12-24 16:49 UTC (permalink / raw)
To: netdev
Cc: Tonghao Zhang, Jamal Hadi Salim, Cong Wang, Jiri Pirko,
David S. Miller, Jakub Kicinski, Jonathan Lemon, Eric Dumazet,
Alexander Lobakin, Paolo Abeni, Talal Ahmad, Kevin Hao,
Ilias Apalodimas, Kees Cook, Kumar Kartikeya Dwivedi,
Antoine Tenart, Wei Wang, Arnd Bergmann
From: Tonghao Zhang <xiangxia.m.yue@gmail.com>
This patch allows user to select queue_mapping, range
from A to B. And user can use skbhash, cgroup classid
and cpuid to select Tx queues. Then we can load balance
packets from A to B queue. The range is an unsigned 16bit
value in decimal format.
$ tc filter ... action skbedit queue_mapping skbhash A B
"skbedit queue_mapping QUEUE_MAPPING" (from "man 8 tc-skbedit")
is enhanced with flags:
* SKBEDIT_F_TXQ_SKBHASH
* SKBEDIT_F_TXQ_CLASSID
* SKBEDIT_F_TXQ_CPUID
Use skb->hash, cgroup classid, or cpuid to distribute packets.
Then same range of tx queues can be shared for different flows,
cgroups, or CPUs in a variety of scenarios.
For example, F1 may share range R1 with F2. The best way to do
that is to set flag to SKBEDIT_F_TXQ_HASH, using skb->hash to
share the queues. If cgroup C1 want to share the R1 with cgroup
C2 .. Cn, use the SKBEDIT_F_TXQ_CLASSID. Of course, in some other
scenario, C1 use R1, while Cn can use the Rn.
Cc: Jamal Hadi Salim <jhs@mojatatu.com>
Cc: Cong Wang <xiyou.wangcong@gmail.com>
Cc: Jiri Pirko <jiri@resnulli.us>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: Jonathan Lemon <jonathan.lemon@gmail.com>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Alexander Lobakin <alobakin@pm.me>
Cc: Paolo Abeni <pabeni@redhat.com>
Cc: Talal Ahmad <talalahmad@google.com>
Cc: Kevin Hao <haokexin@gmail.com>
Cc: Ilias Apalodimas <ilias.apalodimas@linaro.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Cc: Antoine Tenart <atenart@kernel.org>
Cc: Wei Wang <weiwan@google.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Tonghao Zhang <xiangxia.m.yue@gmail.com>
---
include/net/tc_act/tc_skbedit.h | 1 +
include/uapi/linux/tc_act/tc_skbedit.h | 8 +++
net/sched/act_skbedit.c | 78 +++++++++++++++++++++++++-
3 files changed, 84 insertions(+), 3 deletions(-)
diff --git a/include/net/tc_act/tc_skbedit.h b/include/net/tc_act/tc_skbedit.h
index 00bfee70609e..ee96e0fa6566 100644
--- a/include/net/tc_act/tc_skbedit.h
+++ b/include/net/tc_act/tc_skbedit.h
@@ -17,6 +17,7 @@ struct tcf_skbedit_params {
u32 mark;
u32 mask;
u16 queue_mapping;
+ u16 mapping_mod;
u16 ptype;
struct rcu_head rcu;
};
diff --git a/include/uapi/linux/tc_act/tc_skbedit.h b/include/uapi/linux/tc_act/tc_skbedit.h
index 800e93377218..5ea1438a4d88 100644
--- a/include/uapi/linux/tc_act/tc_skbedit.h
+++ b/include/uapi/linux/tc_act/tc_skbedit.h
@@ -29,6 +29,13 @@
#define SKBEDIT_F_PTYPE 0x8
#define SKBEDIT_F_MASK 0x10
#define SKBEDIT_F_INHERITDSFIELD 0x20
+#define SKBEDIT_F_TXQ_SKBHASH 0x40
+#define SKBEDIT_F_TXQ_CLASSID 0x80
+#define SKBEDIT_F_TXQ_CPUID 0x100
+
+#define SKBEDIT_F_TXQ_HASH_MASK (SKBEDIT_F_TXQ_SKBHASH | \
+ SKBEDIT_F_TXQ_CLASSID | \
+ SKBEDIT_F_TXQ_CPUID)
struct tc_skbedit {
tc_gen;
@@ -45,6 +52,7 @@ enum {
TCA_SKBEDIT_PTYPE,
TCA_SKBEDIT_MASK,
TCA_SKBEDIT_FLAGS,
+ TCA_SKBEDIT_QUEUE_MAPPING_MAX,
__TCA_SKBEDIT_MAX
};
#define TCA_SKBEDIT_MAX (__TCA_SKBEDIT_MAX - 1)
diff --git a/net/sched/act_skbedit.c b/net/sched/act_skbedit.c
index d5799b4fc499..4c209689f8de 100644
--- a/net/sched/act_skbedit.c
+++ b/net/sched/act_skbedit.c
@@ -10,6 +10,7 @@
#include <linux/kernel.h>
#include <linux/skbuff.h>
#include <linux/rtnetlink.h>
+#include <net/cls_cgroup.h>
#include <net/netlink.h>
#include <net/pkt_sched.h>
#include <net/ip.h>
@@ -23,6 +24,38 @@
static unsigned int skbedit_net_id;
static struct tc_action_ops act_skbedit_ops;
+static u16 tcf_skbedit_hash(struct tcf_skbedit_params *params,
+ struct sk_buff *skb)
+{
+ u32 mapping_hash_type = params->flags & SKBEDIT_F_TXQ_HASH_MASK;
+ u16 queue_mapping = params->queue_mapping;
+ u16 mapping_mod = params->mapping_mod;
+ u32 hash = 0;
+
+ switch (mapping_hash_type) {
+ case SKBEDIT_F_TXQ_CLASSID:
+ hash = task_get_classid(skb);
+ break;
+ case SKBEDIT_F_TXQ_SKBHASH:
+ hash = skb_get_hash(skb);
+ break;
+ case SKBEDIT_F_TXQ_CPUID:
+ hash = raw_smp_processor_id();
+ break;
+ case 0:
+ /* Hash type isn't specified. In this case:
+ * hash % mapping_mod == 0
+ */
+ break;
+ default:
+ net_warn_ratelimited("The type of queue_mapping hash is not supported. 0x%x\n",
+ mapping_hash_type);
+ }
+
+ queue_mapping = queue_mapping + hash % mapping_mod;
+ return netdev_cap_txqueue(skb->dev, queue_mapping);
+}
+
static int tcf_skbedit_act(struct sk_buff *skb, const struct tc_action *a,
struct tcf_result *res)
{
@@ -62,7 +95,7 @@ static int tcf_skbedit_act(struct sk_buff *skb, const struct tc_action *a,
#ifdef CONFIG_NET_EGRESS
netdev_xmit_skip_txqueue(true);
#endif
- skb_set_queue_mapping(skb, params->queue_mapping);
+ skb_set_queue_mapping(skb, tcf_skbedit_hash(params, skb));
}
if (params->flags & SKBEDIT_F_MARK) {
skb->mark &= ~params->mask;
@@ -96,6 +129,7 @@ static const struct nla_policy skbedit_policy[TCA_SKBEDIT_MAX + 1] = {
[TCA_SKBEDIT_PTYPE] = { .len = sizeof(u16) },
[TCA_SKBEDIT_MASK] = { .len = sizeof(u32) },
[TCA_SKBEDIT_FLAGS] = { .len = sizeof(u64) },
+ [TCA_SKBEDIT_QUEUE_MAPPING_MAX] = { .len = sizeof(u16) },
};
static int tcf_skbedit_init(struct net *net, struct nlattr *nla,
@@ -112,6 +146,7 @@ static int tcf_skbedit_init(struct net *net, struct nlattr *nla,
struct tcf_skbedit *d;
u32 flags = 0, *priority = NULL, *mark = NULL, *mask = NULL;
u16 *queue_mapping = NULL, *ptype = NULL;
+ u16 mapping_mod = 1;
bool exists = false;
int ret = 0, err;
u32 index;
@@ -156,7 +191,34 @@ static int tcf_skbedit_init(struct net *net, struct nlattr *nla,
if (tb[TCA_SKBEDIT_FLAGS] != NULL) {
u64 *pure_flags = nla_data(tb[TCA_SKBEDIT_FLAGS]);
-
+ u64 mapping_hash_type;
+
+ mapping_hash_type = *pure_flags & SKBEDIT_F_TXQ_HASH_MASK;
+ if (mapping_hash_type) {
+ u16 *queue_mapping_max;
+
+ /* Hash types are mutually exclusive. */
+ if (mapping_hash_type & (mapping_hash_type - 1)) {
+ NL_SET_ERR_MSG_MOD(extack, "Multi types of hash are specified.");
+ return -EINVAL;
+ }
+
+ if (!tb[TCA_SKBEDIT_QUEUE_MAPPING] ||
+ !tb[TCA_SKBEDIT_QUEUE_MAPPING_MAX]) {
+ NL_SET_ERR_MSG_MOD(extack, "Missing required range of queue_mapping.");
+ return -EINVAL;
+ }
+
+ queue_mapping_max =
+ nla_data(tb[TCA_SKBEDIT_QUEUE_MAPPING_MAX]);
+ if (*queue_mapping_max < *queue_mapping) {
+ NL_SET_ERR_MSG_MOD(extack, "The range of queue_mapping is invalid, max < min.");
+ return -EINVAL;
+ }
+
+ mapping_mod = *queue_mapping_max - *queue_mapping + 1;
+ flags |= mapping_hash_type;
+ }
if (*pure_flags & SKBEDIT_F_INHERITDSFIELD)
flags |= SKBEDIT_F_INHERITDSFIELD;
}
@@ -208,8 +270,10 @@ static int tcf_skbedit_init(struct net *net, struct nlattr *nla,
params_new->flags = flags;
if (flags & SKBEDIT_F_PRIORITY)
params_new->priority = *priority;
- if (flags & SKBEDIT_F_QUEUE_MAPPING)
+ if (flags & SKBEDIT_F_QUEUE_MAPPING) {
params_new->queue_mapping = *queue_mapping;
+ params_new->mapping_mod = mapping_mod;
+ }
if (flags & SKBEDIT_F_MARK)
params_new->mark = *mark;
if (flags & SKBEDIT_F_PTYPE)
@@ -276,6 +340,13 @@ static int tcf_skbedit_dump(struct sk_buff *skb, struct tc_action *a,
goto nla_put_failure;
if (params->flags & SKBEDIT_F_INHERITDSFIELD)
pure_flags |= SKBEDIT_F_INHERITDSFIELD;
+ if (params->flags & SKBEDIT_F_TXQ_HASH_MASK) {
+ if (nla_put_u16(skb, TCA_SKBEDIT_QUEUE_MAPPING_MAX,
+ params->queue_mapping + params->mapping_mod - 1))
+ goto nla_put_failure;
+
+ pure_flags |= params->flags & SKBEDIT_F_TXQ_HASH_MASK;
+ }
if (pure_flags != 0 &&
nla_put(skb, TCA_SKBEDIT_FLAGS, sizeof(pure_flags), &pure_flags))
goto nla_put_failure;
@@ -325,6 +396,7 @@ static size_t tcf_skbedit_get_fill_size(const struct tc_action *act)
return nla_total_size(sizeof(struct tc_skbedit))
+ nla_total_size(sizeof(u32)) /* TCA_SKBEDIT_PRIORITY */
+ nla_total_size(sizeof(u16)) /* TCA_SKBEDIT_QUEUE_MAPPING */
+ + nla_total_size(sizeof(u16)) /* TCA_SKBEDIT_QUEUE_MAPPING_MAX */
+ nla_total_size(sizeof(u32)) /* TCA_SKBEDIT_MARK */
+ nla_total_size(sizeof(u16)) /* TCA_SKBEDIT_PTYPE */
+ nla_total_size(sizeof(u32)) /* TCA_SKBEDIT_MASK */
--
2.27.0
^ permalink raw reply related [flat|nested] 7+ messages in thread