Add randomness to yield debug test

[urcu.git] / urcu.c

diff --git a/urcu.c b/urcu.c
index 7e79207be6a88eaaf6d2b74c0b16b4543368a6fd..83d2fe4d6d9c367796d123fb05286f8305dfc332 100644 (file)
--- a/urcu.c
+++ b/urcu.c
@@ -1,3 +1,13 @@
+/*
+ * urcu.c
+ *
+ * Userspace RCU library
+ *
+ * Copyright February 2009 - Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
+ *
+ * Distributed under GPLv2
+ */
+
 #include <stdio.h>
 #include <pthread.h>
 #include <signal.h>
@@ -22,11 +32,16 @@ struct reader_data {
        int *urcu_active_readers;
 };
 
+#ifdef DEBUG_YIELD
+unsigned int yield_active;
+unsigned int __thread rand_yield;
+#endif
+
 static struct reader_data *reader_data;
 static int num_readers, alloc_readers;
 static int sig_done;
 
-void rcu_write_lock(void)
+void internal_urcu_lock(void)
 {
        int ret;
        ret = pthread_mutex_lock(&urcu_mutex);
@@ -36,7 +51,7 @@ void rcu_write_lock(void)
        }
 }
 
-void rcu_write_unlock(void)
+void internal_urcu_unlock(void)
 {
        int ret;
 
@@ -66,17 +81,24 @@ static void force_mb_all_threads(void)
         */
        if (!reader_data)
                return;
+       debug_yield_write();
        sig_done = 0;
+       debug_yield_write();
        mb();   /* write sig_done before sending the signals */
-       for (index = reader_data; index < reader_data + num_readers; index++)
+       debug_yield_write();
+       for (index = reader_data; index < reader_data + num_readers; index++) {
                pthread_kill(index->tid, SIGURCU);
+               debug_yield_write();
+       }
        /*
         * Wait for sighandler (and thus mb()) to execute on every thread.
         * BUSY-LOOP.
         */
        while (sig_done < num_readers)
                barrier();
+       debug_yield_write();
        mb();   /* read sig_done before ending the barrier */
+       debug_yield_write();
 }
 
 void wait_for_quiescent_state(int parity)
@@ -91,7 +113,7 @@ void wait_for_quiescent_state(int parity)
                /*
                 * BUSY-LOOP.
                 */
-               while (*index->urcu_active_readers != 0)
+               while (index->urcu_active_readers[parity] != 0)
                        barrier();
        }
        /*
@@ -103,15 +125,47 @@ void wait_for_quiescent_state(int parity)
        force_mb_all_threads();
 }
 
+static void switch_qparity(void)
+{
+       int prev_parity;
+
+       /* All threads should read qparity before accessing data structure. */
+       /* Write ptr before changing the qparity */
+       force_mb_all_threads();
+       debug_yield_write();
+       prev_parity = switch_next_urcu_qparity();
+       debug_yield_write();
+
+       /*
+        * Wait for previous parity to be empty of readers.
+        */
+       wait_for_quiescent_state(prev_parity);
+}
+
+void synchronize_rcu(void)
+{
+       debug_yield_write();
+       internal_urcu_lock();
+       debug_yield_write();
+       switch_qparity();
+       debug_yield_write();
+       switch_qparity();
+       debug_yield_write();
+       internal_urcu_lock();
+       debug_yield_write();
+}
+
 /*
  * Return old pointer, OK to free, no more reference exist.
  * Called under rcu_write_lock.
  */
 void *urcu_publish_content(void **ptr, void *new)
 {
-       int ret, prev_parity;
        void *oldptr;
 
+       debug_yield_write();
+       internal_urcu_lock();
+       debug_yield_write();
        /*
         * We can publish the new pointer before we change the current qparity.
         * Readers seeing the new pointer while being in the previous qparity
@@ -123,20 +177,17 @@ void *urcu_publish_content(void **ptr, void *new)
         * when the next quiescent state window will be over.
         */
        oldptr = *ptr;
+       debug_yield_write();
        *ptr = new;
-       wmb();          /* Write ptr before changing the qparity */
-       /* All threads should read qparity before ptr */
-       force_mb_all_threads();
-       prev_parity = switch_next_urcu_qparity();
 
-       /*
-        * Wait for previous parity to be empty of readers.
-        */
-       wait_for_quiescent_state(prev_parity);
-       /*
-        * Deleting old data is ok !
-        */
-       
+       debug_yield_write();
+       switch_qparity();
+       debug_yield_write();
+       switch_qparity();
+       debug_yield_write();
+       internal_urcu_unlock();
+       debug_yield_write();
+
        return oldptr;
 }
 
@@ -175,7 +226,7 @@ void urcu_remove_reader(pthread_t id)
 
        assert(reader_data != NULL);
        for (index = reader_data; index < reader_data + num_readers; index++) {
-               if (index->tid == id) {
+               if (pthread_equal(index->tid, id)) {
                        memcpy(index, &reader_data[num_readers - 1],
                                sizeof(struct reader_data));
                        reader_data[num_readers - 1].tid = 0;
@@ -190,17 +241,16 @@ void urcu_remove_reader(pthread_t id)
 
 void urcu_register_thread(void)
 {
-       rcu_write_lock();
+       internal_urcu_lock();
        urcu_add_reader(pthread_self());
-       rcu_write_unlock();
+       internal_urcu_unlock();
 }
 
 void urcu_unregister_thread(void)
 {
-       pthread_t self = pthread_self();
-       rcu_write_lock();
+       internal_urcu_lock();
        urcu_remove_reader(pthread_self());
-       rcu_write_unlock();
+       internal_urcu_unlock();
 }
 
 void sigurcu_handler(int signo, siginfo_t *siginfo, void *context)