diff mbox series

[net-next,16/20] tcp: avoid indirect calls to sock_rfree

Message ID 20211115190249.3936899-17-eric.dumazet@gmail.com (mailing list archive)
State Accepted
Delegated to: Netdev Maintainers
Headers show
Series tcp: optimizations for linux-5.17 | expand

Checks

Context Check Description
netdev/tree_selection success Clearly marked for net-next
netdev/fixes_present success Fixes tag not required for -next series
netdev/subject_prefix success Link
netdev/cover_letter success Series has a cover letter
netdev/patch_count fail Series longer than 15 patches (and no cover letter)
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 2 this patch: 2
netdev/cc_maintainers warning 2 maintainers not CCed: yoshfuji@linux-ipv6.org dsahern@kernel.org
netdev/build_clang success Errors and warnings before: 22 this patch: 22
netdev/module_param success Was 0 now: 0
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn success Errors and warnings before: 6 this patch: 6
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 53 lines checked
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0

Commit Message

Eric Dumazet Nov. 15, 2021, 7:02 p.m. UTC 
From: Eric Dumazet <edumazet@google.com>

TCP uses sk_eat_skb() when skbs can be removed from receive queue.
However, the call so skb_orphan() from __kfree_skb() incurs
an indirect call so sock_rfee(), which is more expensive than
a direct call, especially for CONFIG_RETPOLINE=y.

Add tcp_eat_recv_skb() function to make the call before
__kfree_skb().

Signed-off-by: Eric Dumazet <edumazet@google.com>
---
 net/ipv4/tcp.c | 20 +++++++++++++++-----
 1 file changed, 15 insertions(+), 5 deletions(-)
diff mbox series

Patch

diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 9175e0d729f5e65b5fa39acadc5bf9de715854ad..4e7011672aa9a04370b7a03b972fe19cd48ea232 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -1580,6 +1580,16 @@  void tcp_cleanup_rbuf(struct sock *sk, int copied)
 		tcp_send_ack(sk);
 }
 
+static void tcp_eat_recv_skb(struct sock *sk, struct sk_buff *skb)
+{
+	if (likely(skb->destructor == sock_rfree)) {
+		sock_rfree(skb);
+		skb->destructor = NULL;
+		skb->sk = NULL;
+	}
+	sk_eat_skb(sk, skb);
+}
+
 static struct sk_buff *tcp_recv_skb(struct sock *sk, u32 seq, u32 *off)
 {
 	struct sk_buff *skb;
@@ -1599,7 +1609,7 @@  static struct sk_buff *tcp_recv_skb(struct sock *sk, u32 seq, u32 *off)
 		 * splitted a fat GRO packet, while we released socket lock
 		 * in skb_splice_bits()
 		 */
-		sk_eat_skb(sk, skb);
+		tcp_eat_recv_skb(sk, skb);
 	}
 	return NULL;
 }
@@ -1665,11 +1675,11 @@  int tcp_read_sock(struct sock *sk, read_descriptor_t *desc,
 				continue;
 		}
 		if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN) {
-			sk_eat_skb(sk, skb);
+			tcp_eat_recv_skb(sk, skb);
 			++seq;
 			break;
 		}
-		sk_eat_skb(sk, skb);
+		tcp_eat_recv_skb(sk, skb);
 		if (!desc->count)
 			break;
 		WRITE_ONCE(tp->copied_seq, seq);
@@ -2481,14 +2491,14 @@  static int tcp_recvmsg_locked(struct sock *sk, struct msghdr *msg, size_t len,
 		if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN)
 			goto found_fin_ok;
 		if (!(flags & MSG_PEEK))
-			sk_eat_skb(sk, skb);
+			tcp_eat_recv_skb(sk, skb);
 		continue;
 
 found_fin_ok:
 		/* Process the FIN. */
 		WRITE_ONCE(*seq, *seq + 1);
 		if (!(flags & MSG_PEEK))
-			sk_eat_skb(sk, skb);
+			tcp_eat_recv_skb(sk, skb);
 		break;
 	} while (len > 0);