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Message-Id: <027ebc7d404af07b70f8f9816512b2a485e8f420.1536939423.git.pabeni@redhat.com>
Date: Fri, 14 Sep 2018 17:43:23 +0200
From: Paolo Abeni <pabeni@...hat.com>
To: netdev@...r.kernel.org
Cc: "David S. Miller" <davem@...emloft.net>,
Willem de Bruijn <willemb@...gle.com>,
Steffen Klassert <steffen.klassert@...unet.com>
Subject: [RFC PATCH 3/4] udp: implement GRO plain UDP sockets.
This is the RX counter part of commit bec1f6f69736 ("udp: generate gso
with UDP_SEGMENT"). When UDP_SEGMENT is enabled, such socket is also
eligible for GRO in the rx path: UDP segments directed to such socket
are assembled into a larger GSO_UDP_L4 packet.
The core UDP GRO support is enabled/updated on setsockopt(UDP_SEGMENT) and
disabled, if needed at socket destruction time.
Initial benchmark numbers:
Before:
udp rx: 1079 MB/s 769065 calls/s
After:
udp rx: 1466 MB/s 24877 calls/s
This change introduces a side effect in respect to UDP tunnels:
after an UDP tunnel creation, now the kernel performs a lookup per ingress UDP
packet, before such lookup happended only if the ingress packet carried a valid
internal header csum.
Signed-off-by: Paolo Abeni <pabeni@...hat.com>
---
include/linux/udp.h | 2 +-
net/ipv4/udp.c | 1 +
net/ipv4/udp_offload.c | 107 +++++++++++++++++++++++++++++++++--------
net/ipv6/udp_offload.c | 6 +--
4 files changed, 90 insertions(+), 26 deletions(-)
diff --git a/include/linux/udp.h b/include/linux/udp.h
index 56a321a55ba1..27dea956ef6e 100644
--- a/include/linux/udp.h
+++ b/include/linux/udp.h
@@ -128,7 +128,7 @@ static inline bool udp_get_gro_in_use(struct sock *sk)
static inline bool udp_want_gro(struct sock *sk)
{
- return udp_sk(sk)->gro_receive;
+ return udp_sk(sk)->gro_receive || udp_sk(sk)->gso_size;
}
#define udp_portaddr_for_each_entry(__sk, list) \
diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index 5ac794230013..871ee55afd96 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -2450,6 +2450,7 @@ int udp_lib_setsockopt(struct sock *sk, int level, int optname,
if (val < 0 || val > USHRT_MAX)
return -EINVAL;
up->gso_size = val;
+ udp_update_gro_in_use(sk, udp_want_gro(sk));
break;
/*
diff --git a/net/ipv4/udp_offload.c b/net/ipv4/udp_offload.c
index 08b225adf763..4ff150bb84de 100644
--- a/net/ipv4/udp_offload.c
+++ b/net/ipv4/udp_offload.c
@@ -347,6 +347,54 @@ static struct sk_buff *udp4_ufo_fragment(struct sk_buff *skb,
return segs;
}
+#define UDO_GRO_CNT_MAX 64
+static struct sk_buff *udp_gro_receive_segment(struct list_head *head,
+ struct sk_buff *skb)
+{
+ struct udphdr *uh = udp_hdr(skb);
+ struct sk_buff *pp = NULL;
+ struct udphdr *uh2;
+ struct sk_buff *p;
+
+ /* requires non zero csum, for simmetry with GSO */
+ if (!uh->check) {
+ NAPI_GRO_CB(skb)->flush = 1;
+ return NULL;
+ }
+
+ /* pull encapsulating udp header */
+ skb_gro_pull(skb, sizeof(struct udphdr));
+ skb_gro_postpull_rcsum(skb, uh, sizeof(struct udphdr));
+
+ list_for_each_entry(p, head, list) {
+ if (!NAPI_GRO_CB(p)->same_flow)
+ continue;
+
+ uh2 = udp_hdr(p);
+
+ /* Match ports only, as csum is always non zero */
+ if ((*(u32 *)&uh->source != *(u32 *)&uh2->source)) {
+ NAPI_GRO_CB(p)->same_flow = 0;
+ continue;
+ }
+
+ /* Terminate the flow on len mismatch or if it grow "too much".
+ * Under small packet flood GRO count could elsewhere grow a lot
+ * leading to execessive truesize values
+ */
+ if (!skb_gro_receive(p, skb) &&
+ NAPI_GRO_CB(p)->count > UDO_GRO_CNT_MAX)
+ pp = p;
+ else if (uh->len != uh2->len)
+ pp = p;
+
+ return pp;
+ }
+
+ /* mismatch, but we never need to flush */
+ return NULL;
+}
+
struct sk_buff *udp_gro_receive(struct list_head *head, struct sk_buff *skb,
struct udphdr *uh, udp_lookup_t lookup)
{
@@ -357,23 +405,29 @@ struct sk_buff *udp_gro_receive(struct list_head *head, struct sk_buff *skb,
int flush = 1;
struct sock *sk;
+ rcu_read_lock();
+ sk = (*lookup)(skb, uh->source, uh->dest);
+ if (!sk)
+ goto out_unlock;
+
+ if (udp_sk(sk)->gso_size) {
+ pp = call_gro_receive(udp_gro_receive_segment, head, skb);
+ rcu_read_unlock();
+ return pp;
+ }
+
if (NAPI_GRO_CB(skb)->encap_mark ||
(skb->ip_summed != CHECKSUM_PARTIAL &&
NAPI_GRO_CB(skb)->csum_cnt == 0 &&
!NAPI_GRO_CB(skb)->csum_valid))
- goto out;
+ goto out_unlock;
/* mark that this skb passed once through the tunnel gro layer */
NAPI_GRO_CB(skb)->encap_mark = 1;
- rcu_read_lock();
- sk = (*lookup)(skb, uh->source, uh->dest);
-
- if (sk && udp_sk(sk)->gro_receive)
- goto unflush;
- goto out_unlock;
+ if (!udp_sk(sk)->gro_receive)
+ goto out_unlock;
-unflush:
flush = 0;
list_for_each_entry(p, head, list) {
@@ -398,7 +452,6 @@ struct sk_buff *udp_gro_receive(struct list_head *head, struct sk_buff *skb,
out_unlock:
rcu_read_unlock();
-out:
skb_gro_flush_final(skb, pp, flush);
return pp;
}
@@ -431,6 +484,19 @@ static struct sk_buff *udp4_gro_receive(struct list_head *head,
return NULL;
}
+static int udp_gro_complete_segment(struct sk_buff *skb)
+{
+ struct udphdr *uh = udp_hdr(skb);
+
+ skb->csum_start = (unsigned char *)uh - skb->head;
+ skb->csum_offset = offsetof(struct udphdr, check);
+ skb->ip_summed = CHECKSUM_PARTIAL;
+
+ skb_shinfo(skb)->gso_segs = NAPI_GRO_CB(skb)->count;
+ skb_shinfo(skb)->gso_type |= SKB_GSO_UDP_L4;
+ return 0;
+}
+
int udp_gro_complete(struct sk_buff *skb, int nhoff,
udp_lookup_t lookup)
{
@@ -441,16 +507,21 @@ int udp_gro_complete(struct sk_buff *skb, int nhoff,
uh->len = newlen;
- /* Set encapsulation before calling into inner gro_complete() functions
- * to make them set up the inner offsets.
- */
- skb->encapsulation = 1;
-
rcu_read_lock();
sk = (*lookup)(skb, uh->source, uh->dest);
- if (sk && udp_sk(sk)->gro_complete)
+ if (sk && udp_sk(sk)->gso_size) {
+ err = udp_gro_complete_segment(skb);
+ } else if (sk && udp_sk(sk)->gro_complete) {
+ skb_shinfo(skb)->gso_type = uh->check ? SKB_GSO_UDP_TUNNEL_CSUM
+ : SKB_GSO_UDP_TUNNEL;
+
+ /* Set encapsulation before calling into inner gro_complete()
+ * functions to make them set up the inner offsets.
+ */
+ skb->encapsulation = 1;
err = udp_sk(sk)->gro_complete(sk, skb,
nhoff + sizeof(struct udphdr));
+ }
rcu_read_unlock();
if (skb->remcsum_offload)
@@ -465,13 +536,9 @@ static int udp4_gro_complete(struct sk_buff *skb, int nhoff)
const struct iphdr *iph = ip_hdr(skb);
struct udphdr *uh = (struct udphdr *)(skb->data + nhoff);
- if (uh->check) {
- skb_shinfo(skb)->gso_type |= SKB_GSO_UDP_TUNNEL_CSUM;
+ if (uh->check)
uh->check = ~udp_v4_check(skb->len - nhoff, iph->saddr,
iph->daddr, 0);
- } else {
- skb_shinfo(skb)->gso_type |= SKB_GSO_UDP_TUNNEL;
- }
return udp_gro_complete(skb, nhoff, udp4_lib_lookup_skb);
}
diff --git a/net/ipv6/udp_offload.c b/net/ipv6/udp_offload.c
index 1df968a3e788..f2731b7b4c75 100644
--- a/net/ipv6/udp_offload.c
+++ b/net/ipv6/udp_offload.c
@@ -147,13 +147,9 @@ static int udp6_gro_complete(struct sk_buff *skb, int nhoff)
const struct ipv6hdr *ipv6h = ipv6_hdr(skb);
struct udphdr *uh = (struct udphdr *)(skb->data + nhoff);
- if (uh->check) {
- skb_shinfo(skb)->gso_type |= SKB_GSO_UDP_TUNNEL_CSUM;
+ if (uh->check)
uh->check = ~udp_v6_check(skb->len - nhoff, &ipv6h->saddr,
&ipv6h->daddr, 0);
- } else {
- skb_shinfo(skb)->gso_type |= SKB_GSO_UDP_TUNNEL;
- }
return udp_gro_complete(skb, nhoff, udp6_lib_lookup_skb);
}
--
2.17.1
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