X-Git-Url: https://git.liburcu.org/?p=urcu.git;a=blobdiff_plain;f=urcu-defer-impl.h;h=34d99c92997641323175c909f13f793fa27df33d;hp=0aedd53011cc70f5dfc626dc4380caa8aaca823b;hb=1f689e13ea7e519b1afc001e9c55a7b1b60b599f;hpb=0376e7b2f8d26778ebc4750b34e718c062c92764

diff --git a/urcu-defer-impl.h b/urcu-defer-impl.h
index 0aedd53..34d99c9 100644
--- a/urcu-defer-impl.h
+++ b/urcu-defer-impl.h
@@ -38,14 +38,14 @@
 #include <errno.h>
 #include <poll.h>
 #include <sys/time.h>
-#include <syscall.h>
 #include <unistd.h>
+#include <stdint.h>
 
-#include "urcu/urcu-futex.h"
+#include "urcu/futex.h"
 
 #include <urcu/compiler.h>
 #include <urcu/arch.h>
-#include <urcu/uatomic_arch.h>
+#include <urcu/uatomic.h>
 #include <urcu/list.h>
 #include <urcu/system.h>
 
@@ -61,7 +61,9 @@
  * Assumes that (void *)-2L is not used often. Used to encode non-aligned
  * functions and non-aligned data using extra space.
  * We encode the (void *)-2L fct as: -2L, fct, data.
- * We encode the (void *)-2L data as: -2L, fct, data.
+ * We encode the (void *)-2L data as either:
+ *   fct | DQ_FCT_BIT, data (if fct is aligned), or
+ *   -2L, fct, data (if fct is not aligned).
  * Here, DQ_FCT_MARK == ~DQ_FCT_BIT. Required for the test order.
  */
 #define DQ_FCT_BIT		(1 << 0)
@@ -121,7 +123,8 @@ extern void synchronize_rcu(void);
 static pthread_mutex_t rcu_defer_mutex = PTHREAD_MUTEX_INITIALIZER;
 static pthread_mutex_t defer_thread_mutex = PTHREAD_MUTEX_INITIALIZER;
 
-static int defer_thread_futex;
+static int32_t defer_thread_futex;
+static int32_t defer_thread_stop;
 
 /*
  * Written to only by each individual deferer. Read by both the deferer and
@@ -148,7 +151,6 @@ static void mutex_lock_defer(pthread_mutex_t *mutex)
 			perror("Error in pthread mutex lock");
 			exit(-1);
 		}
-		pthread_testcancel();
 		poll(NULL,0,10);
 	}
 #endif /* #else #ifndef DISTRUST_SIGNALS_EXTREME */
@@ -186,7 +188,13 @@ static unsigned long rcu_defer_num_callbacks(void)
 static void wait_defer(void)
 {
 	uatomic_dec(&defer_thread_futex);
-	cmm_smp_mb();	/* Write futex before read queue */
+	/* Write futex before read queue */
+	/* Write futex before read defer_thread_stop */
+	cmm_smp_mb();
+	if (_CMM_LOAD_SHARED(defer_thread_stop)) {
+		uatomic_set(&defer_thread_futex, 0);
+		pthread_exit(0);
+	}
 	if (rcu_defer_num_callbacks()) {
 		cmm_smp_mb();	/* Read queue before write futex */
 		/* Callbacks are queued, don't wait. */
@@ -316,14 +324,27 @@ void _defer_rcu(void (*fct)(void *p), void *p)
 		assert(head - CMM_LOAD_SHARED(defer_queue.tail) == 0);
 	}
 
-	if (unlikely(defer_queue.last_fct_in != fct)) {
+	/*
+	 * Encode:
+	 * if the function is not changed and the data is aligned and it is
+	 * not the marker:
+	 *	store the data
+	 * otherwise if the function is aligned and its not the marker:
+	 *	store the function with DQ_FCT_BIT
+	 *	store the data
+	 * otherwise:
+	 *	store the marker (DQ_FCT_MARK)
+	 *	store the function
+	 *	store the data
+	 *
+	 * Decode: see the comments before 'struct defer_queue'
+	 *         or the code in rcu_defer_barrier_queue().
+	 */
+	if (unlikely(defer_queue.last_fct_in != fct
+			|| DQ_IS_FCT_BIT(p)
+			|| p == DQ_FCT_MARK)) {
 		defer_queue.last_fct_in = fct;
 		if (unlikely(DQ_IS_FCT_BIT(fct) || fct == DQ_FCT_MARK)) {
-			/*
-			 * If the function to encode is not aligned or the
-			 * marker, write DQ_FCT_MARK followed by the function
-			 * pointer.
-			 */
 			_CMM_STORE_SHARED(defer_queue.q[head++ & DEFER_QUEUE_MASK],
 				      DQ_FCT_MARK);
 			_CMM_STORE_SHARED(defer_queue.q[head++ & DEFER_QUEUE_MASK],
@@ -333,17 +354,6 @@ void _defer_rcu(void (*fct)(void *p), void *p)
 			_CMM_STORE_SHARED(defer_queue.q[head++ & DEFER_QUEUE_MASK],
 				      fct);
 		}
-	} else {
-		if (unlikely(DQ_IS_FCT_BIT(p) || p == DQ_FCT_MARK)) {
-			/*
-			 * If the data to encode is not aligned or the marker,
-			 * write DQ_FCT_MARK followed by the function pointer.
-			 */
-			_CMM_STORE_SHARED(defer_queue.q[head++ & DEFER_QUEUE_MASK],
-				      DQ_FCT_MARK);
-			_CMM_STORE_SHARED(defer_queue.q[head++ & DEFER_QUEUE_MASK],
-				      fct);
-		}
 	}
 	_CMM_STORE_SHARED(defer_queue.q[head++ & DEFER_QUEUE_MASK], p);
 	cmm_smp_wmb();	/* Publish new pointer before head */
@@ -359,7 +369,6 @@ void _defer_rcu(void (*fct)(void *p), void *p)
 void *thr_defer(void *args)
 {
 	for (;;) {
-		pthread_testcancel();
 		/*
 		 * "Be green". Don't wake up the CPU if there is no RCU work
 		 * to perform whatsoever. Aims at saving laptop battery life by
@@ -396,10 +405,17 @@ static void stop_defer_thread(void)
 	int ret;
 	void *tret;
 
-	pthread_cancel(tid_defer);
+	_CMM_STORE_SHARED(defer_thread_stop, 1);
+	/* Store defer_thread_stop before testing futex */
+	cmm_smp_mb();
 	wake_up_defer();
+
 	ret = pthread_join(tid_defer, &tret);
 	assert(!ret);
+
+	CMM_STORE_SHARED(defer_thread_stop, 0);
+	/* defer thread should always exit when futex value is 0 */
+	assert(uatomic_read(&defer_thread_futex) == 0);
 }
 
 int rcu_defer_register_thread(void)