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authorPaolo Abeni <pabeni@redhat.com>2018-07-30 15:30:45 +0300
committerDavid S. Miller <davem@davemloft.net>2018-07-30 19:31:14 +0300
commite5cf1baf92cb785b90390db1c624948e70c8b8bd (patch)
treee0120e70e86ad96977d6a92b59aebbb1e06af3eb /net/sched/act_mirred.c
parentcd11b164073b719203318227918f9510809d5e10 (diff)
downloadlinux-e5cf1baf92cb785b90390db1c624948e70c8b8bd.tar.xz
act_mirred: use TC_ACT_REINSERT when possible
When mirred is invoked from the ingress path, and it wants to redirect the processed packet, it can now use the TC_ACT_REINSERT action, filling the tcf_result accordingly, and avoiding a per packet skb_clone(). Overall this gives a ~10% improvement in forwarding performance for the TC S/W data path and TC S/W performances are now comparable to the kernel openvswitch datapath. v1 -> v2: use ACT_MIRRED instead of ACT_REDIRECT v2 -> v3: updated after action rename, fixed typo into the commit message v3 -> v4: updated again after action rename, added more comments to the code (JiriP), skip the optimization if the control action need to touch the tcf_result (Paolo) v4 -> v5: fix sparse warning (kbuild bot) Signed-off-by: Paolo Abeni <pabeni@redhat.com> Acked-by: Jiri Pirko <jiri@mellanox.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/sched/act_mirred.c')
-rw-r--r--net/sched/act_mirred.c53
1 files changed, 43 insertions, 10 deletions
diff --git a/net/sched/act_mirred.c b/net/sched/act_mirred.c
index eeb335f03102..b26d060da08e 100644
--- a/net/sched/act_mirred.c
+++ b/net/sched/act_mirred.c
@@ -25,6 +25,7 @@
#include <net/net_namespace.h>
#include <net/netlink.h>
#include <net/pkt_sched.h>
+#include <net/pkt_cls.h>
#include <linux/tc_act/tc_mirred.h>
#include <net/tc_act/tc_mirred.h>
@@ -49,6 +50,18 @@ static bool tcf_mirred_act_wants_ingress(int action)
}
}
+static bool tcf_mirred_can_reinsert(int action)
+{
+ switch (action) {
+ case TC_ACT_SHOT:
+ case TC_ACT_STOLEN:
+ case TC_ACT_QUEUED:
+ case TC_ACT_TRAP:
+ return true;
+ }
+ return false;
+}
+
static void tcf_mirred_release(struct tc_action *a)
{
struct tcf_mirred *m = to_mirred(a);
@@ -171,10 +184,13 @@ static int tcf_mirred(struct sk_buff *skb, const struct tc_action *a,
struct tcf_result *res)
{
struct tcf_mirred *m = to_mirred(a);
+ struct sk_buff *skb2 = skb;
bool m_mac_header_xmit;
struct net_device *dev;
- struct sk_buff *skb2;
int retval, err = 0;
+ bool use_reinsert;
+ bool want_ingress;
+ bool is_redirect;
int m_eaction;
int mac_len;
@@ -196,16 +212,25 @@ static int tcf_mirred(struct sk_buff *skb, const struct tc_action *a,
goto out;
}
- skb2 = skb_clone(skb, GFP_ATOMIC);
- if (!skb2)
- goto out;
+ /* we could easily avoid the clone only if called by ingress and clsact;
+ * since we can't easily detect the clsact caller, skip clone only for
+ * ingress - that covers the TC S/W datapath.
+ */
+ is_redirect = tcf_mirred_is_act_redirect(m_eaction);
+ use_reinsert = skb_at_tc_ingress(skb) && is_redirect &&
+ tcf_mirred_can_reinsert(retval);
+ if (!use_reinsert) {
+ skb2 = skb_clone(skb, GFP_ATOMIC);
+ if (!skb2)
+ goto out;
+ }
/* If action's target direction differs than filter's direction,
* and devices expect a mac header on xmit, then mac push/pull is
* needed.
*/
- if (skb_at_tc_ingress(skb) != tcf_mirred_act_wants_ingress(m_eaction) &&
- m_mac_header_xmit) {
+ want_ingress = tcf_mirred_act_wants_ingress(m_eaction);
+ if (skb_at_tc_ingress(skb) != want_ingress && m_mac_header_xmit) {
if (!skb_at_tc_ingress(skb)) {
/* caught at egress, act ingress: pull mac */
mac_len = skb_network_header(skb) - skb_mac_header(skb);
@@ -216,15 +241,23 @@ static int tcf_mirred(struct sk_buff *skb, const struct tc_action *a,
}
}
+ skb2->skb_iif = skb->dev->ifindex;
+ skb2->dev = dev;
+
/* mirror is always swallowed */
- if (tcf_mirred_is_act_redirect(m_eaction)) {
+ if (is_redirect) {
skb2->tc_redirected = 1;
skb2->tc_from_ingress = skb2->tc_at_ingress;
+
+ /* let's the caller reinsert the packet, if possible */
+ if (use_reinsert) {
+ res->ingress = want_ingress;
+ res->qstats = this_cpu_ptr(m->common.cpu_qstats);
+ return TC_ACT_REINSERT;
+ }
}
- skb2->skb_iif = skb->dev->ifindex;
- skb2->dev = dev;
- if (!tcf_mirred_act_wants_ingress(m_eaction))
+ if (!want_ingress)
err = dev_queue_xmit(skb2);
else
err = netif_receive_skb(skb2);