From 889a9acc54758922b3529ea473a2dac159d85fd5 Mon Sep 17 00:00:00 2001 From: Mateusz Guzik Date: Wed, 8 Feb 2023 09:53:05 +0000 Subject: [PATCH] ipsec: only update lastused when it changes to limit cache-line bouncing. Note that as there is no atomic_store we are hoping the compiler wont speculatively do the store. It is not employed because the size depends on target arch. Sponsored by: Rubicon Communications, LLC ("Netgate") Differential Revision: https://reviews.freebsd.org/D38433 --- sys/netipsec/key.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/sys/netipsec/key.c b/sys/netipsec/key.c index 345c302c2a8..62aa9901943 100644 --- a/sys/netipsec/key.c +++ b/sys/netipsec/key.c @@ -917,6 +917,7 @@ key_allocsp(struct secpolicyindex *spidx, u_int dir) struct spdcache_entry *entry, *lastentry, *tmpentry; struct secpolicy *sp; uint32_t hashv; + time_t ts; int nb_entries; if (!SPDCACHE_ACTIVE()) { @@ -969,7 +970,9 @@ key_allocsp(struct secpolicyindex *spidx, u_int dir) out: if (sp != NULL) { /* found a SPD entry */ - sp->lastused = time_second; + ts = time_second; + if (__predict_false(sp->lastused != ts)) + sp->lastused = ts; KEYDBG(IPSEC_STAMP, printf("%s: return SP(%p)\n", __func__, sp)); KEYDBG(IPSEC_DATA, kdebug_secpolicy(sp));