[src/trunk]: src/sys/net Sprinkle __noinline to reduce gigantic stack frames ...

[riastradh <riastradh%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/e2dbc4669044
branches:  trunk
changeset: 982862:e2dbc4669044
user:      riastradh <riastradh%NetBSD.org@localhost>
date:      Thu Apr 29 17:55:51 2021 +0000

description:
Sprinkle __noinline to reduce gigantic stack frames in ALL kernels.

In principle this might just push a real problem around, but this is
unlikely to be a real problem because:

1. The large stack frames are really only in the setup state machine
   message handlers, which run at the top loop of a thread with a
   shallow stack anyway.

2. If these are inlined, gcc might create multiple nonoverlapping
   stack buffers, whereas if not inlined, the stack frames from
   consecutive or alternative procedure calls would overlap anyway.

(I haven't investigated exactly what's going on leading to ~5 KB-byte
stack frames, but this shuts gcc up, at least, and the hypotheses
sound plausible to me!)

diffstat:

 sys/net/if_wg.c |  14 +++++++-------
 1 files changed, 7 insertions(+), 7 deletions(-)

diffs (63 lines):

diff -r 9dbb8b86231d -r e2dbc4669044 sys/net/if_wg.c
--- a/sys/net/if_wg.c   Thu Apr 29 17:40:42 2021 +0000
+++ b/sys/net/if_wg.c   Thu Apr 29 17:55:51 2021 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: if_wg.c,v 1.62 2020/11/11 18:08:34 riastradh Exp $     */
+/*     $NetBSD: if_wg.c,v 1.63 2021/04/29 17:55:51 riastradh Exp $     */
 
 /*
  * Copyright (C) Ryota Ozaki <ozaki.ryota%gmail.com@localhost>
@@ -41,7 +41,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: if_wg.c,v 1.62 2020/11/11 18:08:34 riastradh Exp $");
+__KERNEL_RCSID(0, "$NetBSD: if_wg.c,v 1.63 2021/04/29 17:55:51 riastradh Exp $");
 
 #ifdef _KERNEL_OPT
 #include "opt_altq_enabled.h"
@@ -1075,7 +1075,7 @@
        WG_DUMP_HASH("out3", out3);
 }
 
-static void
+static void __noinline
 wg_algo_dh_kdf(uint8_t ckey[WG_CHAINING_KEY_LEN],
     uint8_t cipher_key[WG_CIPHER_KEY_LEN],
     const uint8_t local_key[WG_STATIC_KEY_LEN],
@@ -1407,7 +1407,7 @@
        WG_DLOG("%s: sender=%x\n", __func__, wgs->wgs_local_index);
 }
 
-static void
+static void __noinline
 wg_handle_msg_init(struct wg_softc *wg, const struct wg_msg_init *wgmi,
     const struct sockaddr *src)
 {
@@ -1838,7 +1838,7 @@
        wgp->wgp_session_unstable = wgs_prev;
 }
 
-static void
+static void __noinline
 wg_handle_msg_resp(struct wg_softc *wg, const struct wg_msg_resp *wgmr,
     const struct sockaddr *src)
 {
@@ -2497,7 +2497,7 @@
        wg_put_sa(wgp, wgsa, &psref);
 }
 
-static void
+static void __noinline
 wg_handle_msg_data(struct wg_softc *wg, struct mbuf *m,
     const struct sockaddr *src)
 {
@@ -2714,7 +2714,7 @@
                kmem_intr_free(encrypted_buf, encrypted_len);
 }
 
-static void
+static void __noinline
 wg_handle_msg_cookie(struct wg_softc *wg, const struct wg_msg_cookie *wgmc)
 {
        struct wg_session *wgs;