From f1ea03c9f47eb0d8e31c33e8e7f9f73ea5f9ab03 Mon Sep 17 00:00:00 2001 From: Taylor R Campbell Date: Thu, 31 Mar 2022 02:41:33 +0000 Subject: [PATCH 38/49] callout(9): Convert membar_exit/store to atomic_store_release. Leave an XXX comment to make it clearer what this pairs with. --- sys/kern/kern_timeout.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/sys/kern/kern_timeout.c b/sys/kern/kern_timeout.c index cc3277f9bebe..aea725515a72 100644 --- a/sys/kern/kern_timeout.c +++ b/sys/kern/kern_timeout.c @@ -593,9 +593,11 @@ callout_bind(callout_t *cs, struct cpu_info *ci) * structure, as we don't hold the new CPU's lock. * Issue memory barrier to prevent accesses being * reordered. + * + * XXX Pairs with acquire barrier implied by + * mutex_enter in callout_lock? Unclear... */ - membar_exit(); - c->c_cpu = cc; + atomic_store_release(&c->c_cpu, cc); } mutex_spin_exit(lock); }