From b53f8a67649a371a38dc6d97b0dfe52111236a3e Mon Sep 17 00:00:00 2001 From: Rickard Green Date: Tue, 1 Jun 2010 13:50:50 +0000 Subject: OTP-8658 Add missing memory barriers in erts_poll() Missing memory barriers in erts_poll() could cause the runtime system to hang indefinitely. --- erts/include/internal/ethread.h | 22 +++++++++++++++++----- 1 file changed, 17 insertions(+), 5 deletions(-) (limited to 'erts/include/internal/ethread.h') diff --git a/erts/include/internal/ethread.h b/erts/include/internal/ethread.h index 934a79c6f9..564f8f057c 100644 --- a/erts/include/internal/ethread.h +++ b/erts/include/internal/ethread.h @@ -1,19 +1,19 @@ /* * %CopyrightBegin% - * - * Copyright Ericsson AB 2004-2009. All Rights Reserved. - * + * + * Copyright Ericsson AB 2004-2010. All Rights Reserved. + * * The contents of this file are subject to the Erlang Public License, * Version 1.1, (the "License"); you may not use this file except in * compliance with the License. You should have received a copy of the * Erlang Public License along with this software. If not, it can be * retrieved online at http://www.erlang.org/. - * + * * Software distributed under the License is distributed on an "AS IS" * basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See * the License for the specific language governing rights and limitations * under the License. - * + * * %CopyrightEnd% */ @@ -375,6 +375,12 @@ ETHR_INLINE_FUNC_NAME_(ethr_mutex_unlock)(ethr_mutex *mtx) #define ETHR_HAVE_OPTIMIZED_ATOMIC_OPS 1 #define ETHR_HAVE_OPTIMIZED_LOCKS 1 +#define ETHR_MEMORY_BARRIER \ +do { \ + volatile LONG x___ = 0; \ + (void) _InterlockedCompareExchange(&x___, (LONG) 1, (LONG) 0); \ +} while (0) + typedef struct { volatile LONG value; } ethr_atomic_t; @@ -1124,6 +1130,12 @@ ETHR_INLINE_FUNC_NAME_(ethr_write_lock)(ethr_rwlock_t *lock) */ #ifndef ETHR_HAVE_OPTIMIZED_ATOMIC_OPS +/* + * ETHR_MEMORY_BARRIER orders between locked and atomic accesses only, + * i.e. when this atomic fallback is used a noop is sufficient. + */ +#define ETHR_MEMORY_BARRIER + #define ETHR_ATOMIC_ADDR_BITS 4 #define ETHR_ATOMIC_ADDR_SHIFT 3 -- cgit v1.2.3