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[net-next,4/4] tcp: gro: micro optimizations in tcp[4]_gro_complete()

Message ID 20240301193740.3436871-5-edumazet@google.com (mailing list archive)
State Accepted
Commit 8f78010b701d8fdc290063f29fefc09aaaca4085
Delegated to: Netdev Maintainers
Headers show
Series net: gro: cleanups and fast path refinement | expand

Checks

Context Check Description
netdev/series_format success Posting correctly formatted
netdev/tree_selection success Clearly marked for net-next
netdev/ynl success Generated files up to date; no warnings/errors; no diff in generated;
netdev/fixes_present success Fixes tag not required for -next series
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 946 this patch: 946
netdev/build_tools success No tools touched, skip
netdev/cc_maintainers warning 1 maintainers not CCed: dsahern@kernel.org
netdev/build_clang success Errors and warnings before: 957 this patch: 957
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/deprecated_api success None detected
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn success Errors and warnings before: 962 this patch: 962
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 37 lines checked
netdev/build_clang_rust success No Rust files in patch. Skipping build
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0
netdev/contest success net-next-2024-03-05--06-00 (tests: 891)

Commit Message

Eric Dumazet March 1, 2024, 7:37 p.m. UTC 
In tcp_gro_complete() :

Moving the skb->inner_transport_header setting
allows the compiler to reuse the previously loaded value
of skb->transport_header.

Caching skb_shinfo() avoids duplications as well.

In tcp4_gro_complete(), doing a single change on
skb_shinfo(skb)->gso_type also generates better code.

Signed-off-by: Eric Dumazet <edumazet@google.com>
---
 net/ipv4/tcp_offload.c | 17 +++++++++--------
 1 file changed, 9 insertions(+), 8 deletions(-)
diff mbox series

Patch

diff --git a/net/ipv4/tcp_offload.c b/net/ipv4/tcp_offload.c
index 875456efc92ddd546e13232dd775aaaf1093ce4f..b955ab3b236d965a38054efa004fe12f03074c70 100644
--- a/net/ipv4/tcp_offload.c
+++ b/net/ipv4/tcp_offload.c
@@ -299,18 +299,20 @@  struct sk_buff *tcp_gro_receive(struct list_head *head, struct sk_buff *skb)
 void tcp_gro_complete(struct sk_buff *skb)
 {
 	struct tcphdr *th = tcp_hdr(skb);
+	struct skb_shared_info *shinfo;
+
+	if (skb->encapsulation)
+		skb->inner_transport_header = skb->transport_header;
 
 	skb->csum_start = (unsigned char *)th - skb->head;
 	skb->csum_offset = offsetof(struct tcphdr, check);
 	skb->ip_summed = CHECKSUM_PARTIAL;
 
-	skb_shinfo(skb)->gso_segs = NAPI_GRO_CB(skb)->count;
+	shinfo = skb_shinfo(skb);
+	shinfo->gso_segs = NAPI_GRO_CB(skb)->count;
 
 	if (th->cwr)
-		skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_ECN;
-
-	if (skb->encapsulation)
-		skb->inner_transport_header = skb->transport_header;
+		shinfo->gso_type |= SKB_GSO_TCP_ECN;
 }
 EXPORT_SYMBOL(tcp_gro_complete);
 
@@ -335,10 +337,9 @@  INDIRECT_CALLABLE_SCOPE int tcp4_gro_complete(struct sk_buff *skb, int thoff)
 
 	th->check = ~tcp_v4_check(skb->len - thoff, iph->saddr,
 				  iph->daddr, 0);
-	skb_shinfo(skb)->gso_type |= SKB_GSO_TCPV4;
 
-	if (NAPI_GRO_CB(skb)->is_atomic)
-		skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_FIXEDID;
+	skb_shinfo(skb)->gso_type |= SKB_GSO_TCPV4 |
+			(NAPI_GRO_CB(skb)->is_atomic * SKB_GSO_TCP_FIXEDID);
 
 	tcp_gro_complete(skb);
 	return 0;