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Merge branch 'net-sched-act_skbedit-lockless-data-path'

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Davide Caratti says:

====================
net/sched: act_skbedit: lockless data path

the data path of act_skbedit can be faster if we avoid using spinlocks:
 - patch 1 converts act_skbedit statistics to use per-cpu counters
 - patch 2 lets act_skbedit use RCU to read/update its configuration

test procedure (using pktgen from https://github.com/netoptimizer):

 # ip link add name eth1 type dummy
 # ip link set dev eth1 up
 # tc qdisc add dev eth1 clsact
 # tc filter add dev eth1 egress matchall action skbedit priority c1a0:c1a0
 # for c in 1 2 4 ; do
 > ./pktgen_bench_xmit_mode_queue_xmit.sh -v -s 64 -t $c -n 5000000 -i eth1
 > done

test results (avg. pps/thread)

  $c | before patch |  after patch | improvement
 ----+--------------+--------------+------------
   1 | 3917464 ± 3% | 4000458 ± 3% |  irrelevant
   2 | 3455367 ± 4% | 3953076 ± 1% |        +14%
   4 | 2496594 ± 2% | 3801123 ± 3% |        +52%

v2: rebased on latest net-next
====================

Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
David S. Miller 2018-07-12 14:54:12 -07:00
commit ccb06fba51
2 changed files with 98 additions and 52 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

37
include/net/tc_act/tc_skbedit.h
View File

@ -22,14 +22,19 @@
#include <net/act_api.h>
#include <linux/tc_act/tc_skbedit.h>
struct tcf_skbedit_params {
u32 flags;
u32 priority;
u32 mark;
u32 mask;
u16 queue_mapping;
u16 ptype;
struct rcu_head rcu;
};
struct tcf_skbedit {
struct tc_action common;
u32 flags;
u32 priority;
u32 mark;
u32 mask;
u16 queue_mapping;
u16 ptype;
struct tc_action common;
struct tcf_skbedit_params __rcu *params;
};
#define to_skbedit(a) ((struct tcf_skbedit *)a)
@ -37,15 +42,27 @@ struct tcf_skbedit {
static inline bool is_tcf_skbedit_mark(const struct tc_action *a)
{
#ifdef CONFIG_NET_CLS_ACT
if (a->ops && a->ops->type == TCA_ACT_SKBEDIT)
return to_skbedit(a)->flags == SKBEDIT_F_MARK;
u32 flags;
if (a->ops && a->ops->type == TCA_ACT_SKBEDIT) {
rcu_read_lock();
flags = rcu_dereference(to_skbedit(a)->params)->flags;
rcu_read_unlock();
return flags == SKBEDIT_F_MARK;
}
#endif
return false;
}
static inline u32 tcf_skbedit_mark(const struct tc_action *a)
{
return to_skbedit(a)->mark;
u32 mark;
rcu_read_lock();
mark = rcu_dereference(to_skbedit(a)->params)->mark;
rcu_read_unlock();
return mark;
}
#endif /* __NET_TC_SKBEDIT_H */

113
net/sched/act_skbedit.c
View File

@ -37,14 +37,19 @@ static int tcf_skbedit(struct sk_buff *skb, const struct tc_action *a,
struct tcf_result *res)
{
struct tcf_skbedit *d = to_skbedit(a);
struct tcf_skbedit_params *params;
int action;
spin_lock(&d->tcf_lock);
tcf_lastuse_update(&d->tcf_tm);
bstats_update(&d->tcf_bstats, skb);
bstats_cpu_update(this_cpu_ptr(d->common.cpu_bstats), skb);
if (d->flags & SKBEDIT_F_PRIORITY)
skb->priority = d->priority;
if (d->flags & SKBEDIT_F_INHERITDSFIELD) {
rcu_read_lock();
params = rcu_dereference(d->params);
action = READ_ONCE(d->tcf_action);
if (params->flags & SKBEDIT_F_PRIORITY)
skb->priority = params->priority;
if (params->flags & SKBEDIT_F_INHERITDSFIELD) {
int wlen = skb_network_offset(skb);
switch (tc_skb_protocol(skb)) {
@ -63,23 +68,23 @@ static int tcf_skbedit(struct sk_buff *skb, const struct tc_action *a,
break;
}
}
if (d->flags & SKBEDIT_F_QUEUE_MAPPING &&
skb->dev->real_num_tx_queues > d->queue_mapping)
skb_set_queue_mapping(skb, d->queue_mapping);
if (d->flags & SKBEDIT_F_MARK) {
skb->mark &= ~d->mask;
skb->mark |= d->mark & d->mask;
if (params->flags & SKBEDIT_F_QUEUE_MAPPING &&
skb->dev->real_num_tx_queues > params->queue_mapping)
skb_set_queue_mapping(skb, params->queue_mapping);
if (params->flags & SKBEDIT_F_MARK) {
skb->mark &= ~params->mask;
skb->mark |= params->mark & params->mask;
}
if (d->flags & SKBEDIT_F_PTYPE)
skb->pkt_type = d->ptype;
spin_unlock(&d->tcf_lock);
return d->tcf_action;
if (params->flags & SKBEDIT_F_PTYPE)
skb->pkt_type = params->ptype;
unlock:
rcu_read_unlock();
return action;
err:
d->tcf_qstats.drops++;
spin_unlock(&d->tcf_lock);
return TC_ACT_SHOT;
qstats_drop_inc(this_cpu_ptr(d->common.cpu_qstats));
action = TC_ACT_SHOT;
goto unlock;
}
static const struct nla_policy skbedit_policy[TCA_SKBEDIT_MAX + 1] = {
@ -98,6 +103,7 @@ static int tcf_skbedit_init(struct net *net, struct nlattr *nla,
struct netlink_ext_ack *extack)
{
struct tc_action_net *tn = net_generic(net, skbedit_net_id);
struct tcf_skbedit_params *params_old, *params_new;
struct nlattr *tb[TCA_SKBEDIT_MAX + 1];
struct tc_skbedit *parm;
struct tcf_skbedit *d;
@ -169,7 +175,7 @@ static int tcf_skbedit_init(struct net *net, struct nlattr *nla,
if (!exists) {
ret = tcf_idr_create(tn, parm->index, est, a,
&act_skbedit_ops, bind, false);
&act_skbedit_ops, bind, true);
if (ret) {
tcf_idr_cleanup(tn, parm->index);
return ret;
@ -185,25 +191,34 @@ static int tcf_skbedit_init(struct net *net, struct nlattr *nla,
}
}
spin_lock_bh(&d->tcf_lock);
ASSERT_RTNL();
d->flags = flags;
params_new = kzalloc(sizeof(*params_new), GFP_KERNEL);
if (unlikely(!params_new)) {
if (ret == ACT_P_CREATED)
tcf_idr_release(*a, bind);
return -ENOMEM;
}
params_new->flags = flags;
if (flags & SKBEDIT_F_PRIORITY)
d->priority = *priority;
params_new->priority = *priority;
if (flags & SKBEDIT_F_QUEUE_MAPPING)
d->queue_mapping = *queue_mapping;
params_new->queue_mapping = *queue_mapping;
if (flags & SKBEDIT_F_MARK)
d->mark = *mark;
params_new->mark = *mark;
if (flags & SKBEDIT_F_PTYPE)
d->ptype = *ptype;
params_new->ptype = *ptype;
/* default behaviour is to use all the bits */
d->mask = 0xffffffff;
params_new->mask = 0xffffffff;
if (flags & SKBEDIT_F_MASK)
d->mask = *mask;
params_new->mask = *mask;
d->tcf_action = parm->action;
spin_unlock_bh(&d->tcf_lock);
params_old = rtnl_dereference(d->params);
rcu_assign_pointer(d->params, params_new);
if (params_old)
kfree_rcu(params_old, rcu);
if (ret == ACT_P_CREATED)
tcf_idr_insert(tn, *a);
@ -215,33 +230,36 @@ static int tcf_skbedit_dump(struct sk_buff *skb, struct tc_action *a,
{
unsigned char *b = skb_tail_pointer(skb);
struct tcf_skbedit *d = to_skbedit(a);
struct tcf_skbedit_params *params;
struct tc_skbedit opt = {
.index = d->tcf_index,
.refcnt = refcount_read(&d->tcf_refcnt) - ref,
.bindcnt = atomic_read(&d->tcf_bindcnt) - bind,
.action = d->tcf_action,
};
struct tcf_t t;
u64 pure_flags = 0;
struct tcf_t t;
params = rtnl_dereference(d->params);
if (nla_put(skb, TCA_SKBEDIT_PARMS, sizeof(opt), &opt))
goto nla_put_failure;
if ((d->flags & SKBEDIT_F_PRIORITY) &&
nla_put_u32(skb, TCA_SKBEDIT_PRIORITY, d->priority))
if ((params->flags & SKBEDIT_F_PRIORITY) &&
nla_put_u32(skb, TCA_SKBEDIT_PRIORITY, params->priority))
goto nla_put_failure;
if ((d->flags & SKBEDIT_F_QUEUE_MAPPING) &&
nla_put_u16(skb, TCA_SKBEDIT_QUEUE_MAPPING, d->queue_mapping))
if ((params->flags & SKBEDIT_F_QUEUE_MAPPING) &&
nla_put_u16(skb, TCA_SKBEDIT_QUEUE_MAPPING, params->queue_mapping))
goto nla_put_failure;
if ((d->flags & SKBEDIT_F_MARK) &&
nla_put_u32(skb, TCA_SKBEDIT_MARK, d->mark))
if ((params->flags & SKBEDIT_F_MARK) &&
nla_put_u32(skb, TCA_SKBEDIT_MARK, params->mark))
goto nla_put_failure;
if ((d->flags & SKBEDIT_F_PTYPE) &&
nla_put_u16(skb, TCA_SKBEDIT_PTYPE, d->ptype))
if ((params->flags & SKBEDIT_F_PTYPE) &&
nla_put_u16(skb, TCA_SKBEDIT_PTYPE, params->ptype))
goto nla_put_failure;
if ((d->flags & SKBEDIT_F_MASK) &&
nla_put_u32(skb, TCA_SKBEDIT_MASK, d->mask))
if ((params->flags & SKBEDIT_F_MASK) &&
nla_put_u32(skb, TCA_SKBEDIT_MASK, params->mask))
goto nla_put_failure;
if (d->flags & SKBEDIT_F_INHERITDSFIELD)
if (params->flags & SKBEDIT_F_INHERITDSFIELD)
pure_flags |= SKBEDIT_F_INHERITDSFIELD;
if (pure_flags != 0 &&
nla_put(skb, TCA_SKBEDIT_FLAGS, sizeof(pure_flags), &pure_flags))
@ -257,6 +275,16 @@ nla_put_failure:
return -1;
}
static void tcf_skbedit_cleanup(struct tc_action *a)
{
struct tcf_skbedit *d = to_skbedit(a);
struct tcf_skbedit_params *params;
params = rcu_dereference_protected(d->params, 1);
if (params)
kfree_rcu(params, rcu);
}
static int tcf_skbedit_walker(struct net *net, struct sk_buff *skb,
struct netlink_callback *cb, int type,
const struct tc_action_ops *ops,
@ -289,6 +317,7 @@ static struct tc_action_ops act_skbedit_ops = {
.act = tcf_skbedit,
.dump = tcf_skbedit_dump,
.init = tcf_skbedit_init,
.cleanup = tcf_skbedit_cleanup,
.walk = tcf_skbedit_walker,
.lookup = tcf_skbedit_search,
.delete = tcf_skbedit_delete,