Build urcu-qsbr.so library, update README

[urcu.git] / urcu-qsbr.c

diff --git a/urcu-qsbr.c b/urcu-qsbr.c
index 48bc62ec25e09e18395970d591f9dc64b57a1ed7..300eb970e17f5031be51d4421a1e4a3a0080cd38 100644 (file)
--- a/urcu-qsbr.c
+++ b/urcu-qsbr.c
@@ -1,7 +1,7 @@
 /*
- * urcu.c
+ * urcu-qsbr.c
  *
- * Userspace RCU library
+ * Userspace RCU QSBR library
  *
  * Copyright (c) 2009 Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
  * Copyright (c) 2009 Paul E. McKenney, IBM Corporation.
@@ -32,9 +32,9 @@
 #include <errno.h>
 #include <poll.h>
 
-#include "urcu-static.h"
+#include "urcu-qsbr-static.h"
 /* Do not #define _LGPL_SOURCE to ensure we can emit the wrapper symbols */
-#include "urcu.h"
+#include "urcu-qsbr.h"
 
 pthread_mutex_t urcu_mutex = PTHREAD_MUTEX_INITIALIZER;
 
@@ -47,14 +47,14 @@ long urcu_gp_ctr = 0;
  * Written to only by each individual reader. Read by both the reader and the
  * writers.
  */
-long __thread urcu_active_readers;
+long __thread rcu_reader_qs_gp;
 
 /* Thread IDs of registered readers */
 #define INIT_NUM_THREADS 4
 
 struct reader_registry {
        pthread_t tid;
-       long *urcu_active_readers;
+       long *rcu_reader_qs_gp;
        char *need_mb;
 };
 
@@ -124,19 +124,21 @@ void wait_for_quiescent_state(void)
        if (!registry)
                return;
        /*
-        * Wait for each thread urcu_active_readers count to become 0.
+        * Wait for each thread rcu_reader_qs_gp count to become 0.
         */
        for (index = registry; index < registry + num_readers; index++) {
 #ifndef HAS_INCOHERENT_CACHES
-               while (rcu_old_gp_ongoing(index->urcu_active_readers))
+               while (rcu_gp_ongoing(index->rcu_reader_qs_gp) &&
+                      (*index->rcu_reader_qs_gp - urcu_gp_ctr < 0))
                        cpu_relax();
 #else /* #ifndef HAS_INCOHERENT_CACHES */
                int wait_loops = 0;
                /*
                 * BUSY-LOOP. Force the reader thread to commit its
-                * urcu_active_readers update to memory if we wait for too long.
+                * rcu_reader_qs_gp update to memory if we wait for too long.
                 */
-               while (rcu_old_gp_ongoing(index->urcu_active_readers)) {
+               while (rcu_gp_ongoing(index->rcu_reader_qs_gp) &&
+                      (*index->rcu_reader_qs_gp - urcu_gp_ctr < 0)) {
                        if (wait_loops++ == KICK_READER_LOOPS) {
                                force_mb_single_thread(index);
                                wait_loops = 0;
@@ -198,6 +200,21 @@ void *rcu_publish_content_sym(void **p, void *v)
        return oldptr;
 }
 
+void rcu_quiescent_state(void)
+{
+       _rcu_quiescent_state();
+}
+
+void rcu_thread_offline(void)
+{
+       _rcu_thread_offline();
+}
+
+void rcu_thread_online(void)
+{
+       _rcu_thread_online();
+}
+
 static void rcu_add_reader(pthread_t id)
 {
        struct reader_registry *oldarray;
@@ -219,7 +236,7 @@ static void rcu_add_reader(pthread_t id)
        }
        registry[num_readers].tid = id;
        /* reference to the TLS of _this_ reader thread. */
-       registry[num_readers].urcu_active_readers = &urcu_active_readers;
+       registry[num_readers].rcu_reader_qs_gp = &rcu_reader_qs_gp;
        registry[num_readers].need_mb = &need_mb;
        num_readers++;
 }
@@ -238,7 +255,7 @@ static void rcu_remove_reader(pthread_t id)
                        memcpy(index, &registry[num_readers - 1],
                                sizeof(struct reader_registry));
                        registry[num_readers - 1].tid = 0;
-                       registry[num_readers - 1].urcu_active_readers = NULL;
+                       registry[num_readers - 1].rcu_reader_qs_gp = NULL;
                        num_readers--;
                        return;
                }
@@ -252,10 +269,16 @@ void rcu_register_thread(void)
        internal_urcu_lock();
        rcu_add_reader(pthread_self());
        internal_urcu_unlock();
+       _rcu_thread_online();
 }
 
 void rcu_unregister_thread(void)
 {
+       /*
+        * We have to make the thread offline otherwise we end up dealocking
+        * with a waiting writer.
+        */
+       _rcu_thread_offline();
        internal_urcu_lock();
        rcu_remove_reader(pthread_self());
        internal_urcu_unlock();