From 5c1ebbfabcd61142a4551bfc0e51840f9bdae7af Mon Sep 17 00:00:00 2001 From: Brian Vazquez Date: Wed, 1 Mar 2023 13:32:47 +0000 Subject: [PATCH] net: use indirect calls helpers for sk_exit_memory_pressure() Florian reported a regression and sent a patch with the following changelog: There is a noticeable tcp performance regression (loopback or cross-netns), seen with iperf3 -Z (sendfile mode) when generic retpolines are needed. With SK_RECLAIM_THRESHOLD checks gone number of calls to enter/leave memory pressure happen much more often. For TCP indirect calls are used. We can't remove the if-set-return short-circuit check in tcp_enter_memory_pressure because there are callers other than sk_enter_memory_pressure. Doing a check in the sk wrapper too reduces the indirect calls enough to recover some performance. Before, 0.00-60.00 sec 322 GBytes 46.1 Gbits/sec receiver After: 0.00-60.04 sec 359 GBytes 51.4 Gbits/sec receiver "iperf3 -c $peer -t 60 -Z -f g", connected via veth in another netns. It seems we forgot to upstream this indirect call mitigation we had for years, lets do this instead. [edumazet] - It seems we forgot to upstream this indirect call mitigation we had for years, let's do this instead. - Changed to INDIRECT_CALL_INET_1() to avoid bots reports. Fixes: 4890b686f408 ("net: keep sk->sk_forward_alloc as small as possible") Reported-by: Florian Westphal Link: https://lore.kernel.org/netdev/20230227152741.4a53634b@kernel.org/T/ Signed-off-by: Brian Vazquez Signed-off-by: Eric Dumazet Link: https://lore.kernel.org/r/20230301133247.2346111-1-edumazet@google.com Signed-off-by: Paolo Abeni --- net/core/sock.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/net/core/sock.c b/net/core/sock.c index 341c565dbc26..c25888795390 100644 --- a/net/core/sock.c +++ b/net/core/sock.c @@ -2818,7 +2818,8 @@ static void sk_enter_memory_pressure(struct sock *sk) static void sk_leave_memory_pressure(struct sock *sk) { if (sk->sk_prot->leave_memory_pressure) { - sk->sk_prot->leave_memory_pressure(sk); + INDIRECT_CALL_INET_1(sk->sk_prot->leave_memory_pressure, + tcp_leave_memory_pressure, sk); } else { unsigned long *memory_pressure = sk->sk_prot->memory_pressure; -- GitLab