X-Git-Url: https://git.lttng.org/?p=urcu.git;a=blobdiff_plain;f=urcu.c;h=c07df2e8cf21384a07da3bb47066cd2b2bb44084;hp=2a225c4ed19d4c626b8f7fb9af5efa702bf3f371;hb=c297c21c6eadc359a358d33e65f9f5419b55b586;hpb=8a5fb4c96a1e49623fd9358a048b2cfec3a917f8

diff --git a/urcu.c b/urcu.c
index 2a225c4..c07df2e 100644
--- a/urcu.c
+++ b/urcu.c
@@ -36,8 +36,14 @@
 /* Do not #define _LGPL_SOURCE to ensure we can emit the wrapper symbols */
 #include "urcu.h"
 
+#ifndef DEBUG_FULL_MB
 void __attribute__((constructor)) urcu_init(void);
 void __attribute__((destructor)) urcu_exit(void);
+#else
+static inline urcu_init(void)
+{
+}
+#endif
 
 int init_done;
 
@@ -254,12 +260,11 @@ void synchronize_rcu(void)
 	 */
 
 	/*
-	 * Current RCU formal verification model assumes sequential execution of
-	 * the write-side. Add core synchronization instructions. Can be removed
-	 * if the formal model is extended to prove that reordering is still
-	 * correct.
+	 * Adding a smp_mb() which is _not_ formally required, but makes the
+	 * model easier to understand. It does not have a big performance impact
+	 * anyway, given this is the write-side.
 	 */
-	sync_core();	/* Formal model assumes serialized execution */
+	smp_mb();
 
 	/*
 	 * Wait for previous parity to be empty of readers.
@@ -274,7 +279,12 @@ void synchronize_rcu(void)
 	 * Ensured by STORE_SHARED and LOAD_SHARED.
 	 */
 
-	sync_core();	/* Formal model assumes serialized execution */
+	/*
+	 * Adding a smp_mb() which is _not_ formally required, but makes the
+	 * model easier to understand. It does not have a big performance impact
+	 * anyway, given this is the write-side.
+	 */
+	smp_mb();
 
 	switch_next_urcu_qparity();	/* 1 -> 0 */
 
@@ -286,7 +296,12 @@ void synchronize_rcu(void)
 	 * Ensured by STORE_SHARED and LOAD_SHARED.
 	 */
 
-	sync_core();	/* Formal model assumes serialized execution */
+	/*
+	 * Adding a smp_mb() which is _not_ formally required, but makes the
+	 * model easier to understand. It does not have a big performance impact
+	 * anyway, given this is the write-side.
+	 */
+	smp_mb();
 
 	/*
 	 * Wait for previous parity to be empty of readers.
@@ -436,6 +451,8 @@ void urcu_init(void)
 	init_done = 1;
 
 	act.sa_sigaction = sigurcu_handler;
+	act.sa_flags = SA_SIGINFO;
+	sigemptyset(&act.sa_mask);
 	ret = sigaction(SIGURCU, &act, NULL);
 	if (ret) {
 		perror("Error in sigaction");