From: Eric Dumazet <edumazet@google.com>
To: "David S . Miller" <davem@davemloft.net>,
Jakub Kicinski <kuba@kernel.org>,
Paolo Abeni <pabeni@redhat.com>
Cc: Simon Horman <horms@kernel.org>,
Kuniyuki Iwashima <kuniyu@google.com>,
netdev@vger.kernel.org, eric.dumazet@gmail.com,
Eric Dumazet <edumazet@google.com>
Subject: [PATCH net] indirect_call_wrapper: do not reevaluate function pointer
Date: Fri, 27 Feb 2026 17:26:03 +0000 [thread overview]
Message-ID: <20260227172603.1700433-1-edumazet@google.com> (raw)
We have an increasing number of READ_ONCE(xxx->function)
combined with INDIRECT_CALL_[1234]() helpers.
Unfortunately this forces INDIRECT_CALL_[1234]() to read
xxx->function many times, which is not what we wanted.
Fix these macros so that xxx->function value is not reloaded.
$ scripts/bloat-o-meter -t vmlinux.0 vmlinux
add/remove: 0/0 grow/shrink: 1/65 up/down: 122/-1084 (-962)
Function old new delta
ip_push_pending_frames 59 181 +122
ip6_finish_output 687 681 -6
__udp_enqueue_schedule_skb 1078 1072 -6
ioam6_output 2319 2312 -7
xfrm4_rcv_encap_finish2 64 56 -8
xfrm4_output 297 289 -8
vrf_ip_local_out 278 270 -8
vrf_ip6_local_out 278 270 -8
seg6_input_finish 64 56 -8
rpl_output 700 692 -8
ipmr_forward_finish 124 116 -8
ip_forward_finish 143 135 -8
ip6mr_forward2_finish 100 92 -8
ip6_forward_finish 73 65 -8
input_action_end_bpf 1091 1083 -8
dst_input 52 44 -8
__xfrm6_output 801 793 -8
__xfrm4_output 83 75 -8
bpf_input 500 491 -9
__tcp_check_space 530 521 -9
input_action_end_dt6 291 280 -11
vti6_tnl_xmit 1634 1622 -12
bpf_xmit 1203 1191 -12
rpl_input 497 483 -14
rawv6_send_hdrinc 1355 1341 -14
ndisc_send_skb 1030 1016 -14
ipv6_srh_rcv 1377 1363 -14
ip_send_unicast_reply 1253 1239 -14
ip_rcv_finish 226 212 -14
ip6_rcv_finish 300 286 -14
input_action_end_x_core 205 191 -14
input_action_end_x 355 341 -14
input_action_end_t 205 191 -14
input_action_end_dx6_finish 127 113 -14
input_action_end_dx4_finish 373 359 -14
input_action_end_dt4 426 412 -14
input_action_end_core 186 172 -14
input_action_end_b6_encap 292 278 -14
input_action_end_b6 198 184 -14
igmp6_send 1332 1318 -14
ip_sublist_rcv 864 848 -16
ip6_sublist_rcv 1091 1075 -16
ipv6_rpl_srh_rcv 1937 1920 -17
xfrm_policy_queue_process 1246 1228 -18
seg6_output_core 903 885 -18
mld_sendpack 856 836 -20
NF_HOOK 756 736 -20
vti_tunnel_xmit 1447 1426 -21
input_action_end_dx6 664 642 -22
input_action_end 1502 1480 -22
sock_sendmsg_nosec 134 111 -23
ip6mr_forward2 388 364 -24
sock_recvmsg_nosec 134 109 -25
seg6_input_core 836 810 -26
ip_send_skb 172 146 -26
ip_local_out 140 114 -26
ip6_local_out 140 114 -26
__sock_sendmsg 162 136 -26
__ip_queue_xmit 1196 1170 -26
__ip_finish_output 405 379 -26
ipmr_queue_fwd_xmit 373 346 -27
sock_recvmsg 173 145 -28
ip6_xmit 1635 1607 -28
xfrm_output_resume 1418 1389 -29
ip_build_and_send_pkt 625 591 -34
dst_output 504 432 -72
Total: Before=25217686, After=25216724, chg -0.00%
Fixes: 283c16a2dfd3 ("indirect call wrappers: helpers to speed-up indirect calls of builtin")
Signed-off-by: Eric Dumazet <edumazet@google.com>
---
include/linux/indirect_call_wrapper.h | 18 +++++++++++-------
1 file changed, 11 insertions(+), 7 deletions(-)
diff --git a/include/linux/indirect_call_wrapper.h b/include/linux/indirect_call_wrapper.h
index 35227d47cfc98c14f80a17a01d8df6050c56768e..dc272b514a01b8b318dbcffec6c46a359ee5e767 100644
--- a/include/linux/indirect_call_wrapper.h
+++ b/include/linux/indirect_call_wrapper.h
@@ -16,22 +16,26 @@
*/
#define INDIRECT_CALL_1(f, f1, ...) \
({ \
- likely(f == f1) ? f1(__VA_ARGS__) : f(__VA_ARGS__); \
+ typeof(f) __f1 = (f); \
+ likely(__f1 == f1) ? f1(__VA_ARGS__) : __f1(__VA_ARGS__); \
})
#define INDIRECT_CALL_2(f, f2, f1, ...) \
({ \
- likely(f == f2) ? f2(__VA_ARGS__) : \
- INDIRECT_CALL_1(f, f1, __VA_ARGS__); \
+ typeof(f) __f2 = (f); \
+ likely(__f2 == f2) ? f2(__VA_ARGS__) : \
+ INDIRECT_CALL_1(__f2, f1, __VA_ARGS__); \
})
#define INDIRECT_CALL_3(f, f3, f2, f1, ...) \
({ \
- likely(f == f3) ? f3(__VA_ARGS__) : \
- INDIRECT_CALL_2(f, f2, f1, __VA_ARGS__); \
+ typeof(f) __f3 = (f); \
+ likely(__f3 == f3) ? f3(__VA_ARGS__) : \
+ INDIRECT_CALL_2(__f3, f2, f1, __VA_ARGS__); \
})
#define INDIRECT_CALL_4(f, f4, f3, f2, f1, ...) \
({ \
- likely(f == f4) ? f4(__VA_ARGS__) : \
- INDIRECT_CALL_3(f, f3, f2, f1, __VA_ARGS__); \
+ typeof(f) __f4 = (f); \
+ likely(__f4 == f4) ? f4(__VA_ARGS__) : \
+ INDIRECT_CALL_3(__f4, f3, f2, f1, __VA_ARGS__); \
})
#define INDIRECT_CALLABLE_DECLARE(f) f
--
2.53.0.473.g4a7958ca14-goog
next reply other threads:[~2026-02-27 17:26 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-02-27 17:26 Eric Dumazet [this message]
2026-02-28 19:05 ` [PATCH net] indirect_call_wrapper: do not reevaluate function pointer Kuniyuki Iwashima
2026-03-03 11:50 ` patchwork-bot+netdevbpf
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