X-Git-Url: https://git.liburcu.org/?p=urcu.git;a=blobdiff_plain;f=urcu-call-rcu-impl.h;h=8a89295fa44bcc6dc18b84e671ec42705128ff06;hp=69edd49f422dfdbe36524b64f7037ca66cec34fa;hb=6d841bc23fc94345fe76651d73c1a3f821a85aa7;hpb=263e3cf98bd9b7e6b352e25b8007bd1b6df250b8

diff --git a/urcu-call-rcu-impl.h b/urcu-call-rcu-impl.h
index 69edd49..8a89295 100644
--- a/urcu-call-rcu-impl.h
+++ b/urcu-call-rcu-impl.h
@@ -26,6 +26,7 @@
 #include <signal.h>
 #include <assert.h>
 #include <stdlib.h>
+#include <stdint.h>
 #include <string.h>
 #include <errno.h>
 #include <poll.h>
@@ -39,16 +40,15 @@
 #include "urcu-call-rcu.h"
 #include "urcu-pointer.h"
 #include "urcu/list.h"
-#include "urcu/urcu-futex.h"
+#include "urcu/futex.h"
 
 /* Data structure that identifies a call_rcu thread. */
 
 struct call_rcu_data {
 	struct cds_wfq_queue cbs;
 	unsigned long flags;
-	pthread_mutex_t mtx;
-	int futex;
-	unsigned long qlen;
+	int32_t futex;
+	unsigned long qlen; /* maintained for debugging. */
 	pthread_t tid;
 	int cpu_affinity;
 	struct cds_list_head list;
@@ -204,6 +204,7 @@ static void *call_rcu_thread(void *arg)
 	struct cds_wfq_node **cbs_tail;
 	struct call_rcu_data *crdp = (struct call_rcu_data *)arg;
 	struct rcu_head *rhp;
+	int rt = !!(uatomic_read(&crdp->flags) & URCU_CALL_RCU_RT);
 
 	if (set_thread_cpu_affinity(crdp) != 0) {
 		perror("pthread_setaffinity_np");
@@ -211,6 +212,11 @@ static void *call_rcu_thread(void *arg)
 	}
 
 	thread_call_rcu_data = crdp;
+	if (!rt) {
+		uatomic_dec(&crdp->futex);
+		/* Decrement futex before reading call_rcu list */
+		cmm_smp_mb();
+	}
 	for (;;) {
 		if (&crdp->cbs.head != _CMM_LOAD_SHARED(crdp->cbs.tail)) {
 			while ((cbs = _CMM_LOAD_SHARED(crdp->cbs.head)) == NULL)
@@ -235,19 +241,34 @@ static void *call_rcu_thread(void *arg)
 			} while (cbs != NULL);
 			uatomic_sub(&crdp->qlen, cbcount);
 		}
-		if (crdp->flags & URCU_CALL_RCU_STOP)
+		if (uatomic_read(&crdp->flags) & URCU_CALL_RCU_STOP)
 			break;
-		if (crdp->flags & URCU_CALL_RCU_RT)
-			poll(NULL, 0, 10);
-		else {
-			if (&crdp->cbs.head == _CMM_LOAD_SHARED(crdp->cbs.tail))
+		if (!rt) {
+			if (&crdp->cbs.head
+			    == _CMM_LOAD_SHARED(crdp->cbs.tail)) {
 				call_rcu_wait(crdp);
+				poll(NULL, 0, 10);
+				uatomic_dec(&crdp->futex);
+				/*
+				 * Decrement futex before reading
+				 * call_rcu list.
+				 */
+				cmm_smp_mb();
+			} else {
+				poll(NULL, 0, 10);
+			}
+		} else {
 			poll(NULL, 0, 10);
 		}
 	}
-	call_rcu_lock(&crdp->mtx);
-	crdp->flags |= URCU_CALL_RCU_STOPPED;
-	call_rcu_unlock(&crdp->mtx);
+	if (!rt) {
+		/*
+		 * Read call_rcu list before write futex.
+		 */
+		cmm_smp_mb();
+		uatomic_set(&crdp->futex, 0);
+	}
+	uatomic_or(&crdp->flags, URCU_CALL_RCU_STOPPED);
 	return NULL;
 }
 
@@ -271,10 +292,6 @@ static void call_rcu_data_init(struct call_rcu_data **crdpp,
 	memset(crdp, '\0', sizeof(*crdp));
 	cds_wfq_init(&crdp->cbs);
 	crdp->qlen = 0;
-	if (pthread_mutex_init(&crdp->mtx, NULL) != 0) {
-		perror("pthread_mutex_init");
-		exit(-1);
-	}
 	crdp->futex = 0;
 	crdp->flags = flags;
 	cds_list_add(&crdp->list, &call_rcu_data_list);
@@ -557,12 +574,10 @@ void call_rcu_data_free(struct call_rcu_data *crdp)
 	if (crdp == NULL || crdp == default_call_rcu_data) {
 		return;
 	}
-	if ((crdp->flags & URCU_CALL_RCU_STOPPED) == 0) {
-		call_rcu_lock(&crdp->mtx);
-		crdp->flags |= URCU_CALL_RCU_STOP;
-		call_rcu_unlock(&crdp->mtx);
+	if ((uatomic_read(&crdp->flags) & URCU_CALL_RCU_STOPPED) == 0) {
+		uatomic_or(&crdp->flags, URCU_CALL_RCU_STOP);
 		wake_call_rcu_thread(crdp);
-		while ((crdp->flags & URCU_CALL_RCU_STOPPED) == 0)
+		while ((uatomic_read(&crdp->flags) & URCU_CALL_RCU_STOPPED) == 0)
 			poll(NULL, 0, 1);
 	}
 	if (&crdp->cbs.head != _CMM_LOAD_SHARED(crdp->cbs.tail)) {
@@ -646,7 +661,7 @@ void call_rcu_after_fork_child(void)
 		if (crdp == default_call_rcu_data)
 			crdp = cds_list_entry(crdp->list.prev,
 					      struct call_rcu_data, list);
-		crdp->flags = URCU_CALL_RCU_STOPPED;
+		uatomic_set(&crdp->flags, URCU_CALL_RCU_STOPPED);
 		call_rcu_data_free(crdp);
 	}
 }