diff options
| author | Eric Dumazet <edumazet@google.com> | 2025-03-20 12:16:04 +0000 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2025-03-25 07:37:16 -0700 |
| commit | 0de2a5c4b824da2205658ebebb99a55c43cdf60f (patch) | |
| tree | 35c86479d8dd4f78f78c63164a17f70fc9e72b3a /net | |
| parent | Merge branch 'nexthop-convert-rtm_-new-del-nexthop-to-per-netns-rtnl' (diff) | |
| download | linux-0de2a5c4b824da2205658ebebb99a55c43cdf60f.tar.gz linux-0de2a5c4b824da2205658ebebb99a55c43cdf60f.zip | |
tcp: avoid atomic operations on sk->sk_rmem_alloc
TCP uses generic skb_set_owner_r() and sock_rfree()
for received packets, with socket lock being owned.
Switch to private versions, avoiding two atomic operations
per packet.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Neal Cardwell <ncardwell@google.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Link: https://patch.msgid.link/20250320121604.3342831-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'net')
| -rw-r--r-- | net/ipv4/tcp.c | 18 | ||||
| -rw-r--r-- | net/ipv4/tcp_fastopen.c | 2 | ||||
| -rw-r--r-- | net/ipv4/tcp_input.c | 6 |
3 files changed, 20 insertions, 6 deletions
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index 6edc441b3702..ea8de00f669d 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -1525,11 +1525,25 @@ void tcp_cleanup_rbuf(struct sock *sk, int copied) __tcp_cleanup_rbuf(sk, copied); } +/* private version of sock_rfree() avoiding one atomic_sub() */ +void tcp_sock_rfree(struct sk_buff *skb) +{ + struct sock *sk = skb->sk; + unsigned int len = skb->truesize; + + sock_owned_by_me(sk); + atomic_set(&sk->sk_rmem_alloc, + atomic_read(&sk->sk_rmem_alloc) - len); + + sk_forward_alloc_add(sk, len); + sk_mem_reclaim(sk); +} + static void tcp_eat_recv_skb(struct sock *sk, struct sk_buff *skb) { __skb_unlink(skb, &sk->sk_receive_queue); - if (likely(skb->destructor == sock_rfree)) { - sock_rfree(skb); + if (likely(skb->destructor == tcp_sock_rfree)) { + tcp_sock_rfree(skb); skb->destructor = NULL; skb->sk = NULL; return skb_attempt_defer_free(skb); diff --git a/net/ipv4/tcp_fastopen.c b/net/ipv4/tcp_fastopen.c index 1a6b1bc54245..ca40665145c6 100644 --- a/net/ipv4/tcp_fastopen.c +++ b/net/ipv4/tcp_fastopen.c @@ -189,7 +189,7 @@ void tcp_fastopen_add_skb(struct sock *sk, struct sk_buff *skb) tcp_segs_in(tp, skb); __skb_pull(skb, tcp_hdrlen(skb)); sk_forced_mem_schedule(sk, skb->truesize); - skb_set_owner_r(skb, sk); + tcp_skb_set_owner_r(skb, sk); TCP_SKB_CB(skb)->seq++; TCP_SKB_CB(skb)->tcp_flags &= ~TCPHDR_SYN; diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c index a35018e2d0ba..e1f952fbac48 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -5171,7 +5171,7 @@ end: if (tcp_is_sack(tp)) tcp_grow_window(sk, skb, false); skb_condense(skb); - skb_set_owner_r(skb, sk); + tcp_skb_set_owner_r(skb, sk); } } @@ -5187,7 +5187,7 @@ static int __must_check tcp_queue_rcv(struct sock *sk, struct sk_buff *skb, tcp_rcv_nxt_update(tcp_sk(sk), TCP_SKB_CB(skb)->end_seq); if (!eaten) { tcp_add_receive_queue(sk, skb); - skb_set_owner_r(skb, sk); + tcp_skb_set_owner_r(skb, sk); } return eaten; } @@ -5504,7 +5504,7 @@ skip_this: __skb_queue_before(list, skb, nskb); else __skb_queue_tail(&tmp, nskb); /* defer rbtree insertion */ - skb_set_owner_r(nskb, sk); + tcp_skb_set_owner_r(nskb, sk); mptcp_skb_ext_move(nskb, skb); /* Copy data, releasing collapsed skbs. */ |