1 files changed, 86 insertions, 0 deletions
diff --git a/tools/testing/radix-tree/rcupdate.c b/tools/testing/radix-tree/rcupdate.c
new file mode 100644
index 000000000000..31a2d14225d6
--- /dev/null
+++ b/tools/testing/radix-tree/rcupdate.c
@@ -0,0 +1,86 @@
+#include <linux/rcupdate.h>
+#include <pthread.h>
+#include <stdio.h>
+#include <assert.h>
+
+static pthread_mutex_t rculock = PTHREAD_MUTEX_INITIALIZER;
+static struct rcu_head *rcuhead_global = NULL;
+static __thread int nr_rcuhead = 0;
+static __thread struct rcu_head *rcuhead = NULL;
+static __thread struct rcu_head *rcutail = NULL;
+
+static pthread_cond_t rcu_worker_cond = PTHREAD_COND_INITIALIZER;
+
+/* switch to urcu implementation when it is merged. */
+void call_rcu(struct rcu_head *head, void (*func)(struct rcu_head *head))
+{
+	head->func = func;
+	head->next = rcuhead;
+	rcuhead = head;
+	if (!rcutail)
+		rcutail = head;
+	nr_rcuhead++;
+	if (nr_rcuhead >= 1000) {
+		int signal = 0;
+
+		pthread_mutex_lock(&rculock);
+		if (!rcuhead_global)
+			signal = 1;
+		rcutail->next = rcuhead_global;
+		rcuhead_global = head;
+		pthread_mutex_unlock(&rculock);
+
+		nr_rcuhead = 0;
+		rcuhead = NULL;
+		rcutail = NULL;
+
+		if (signal) {
+			pthread_cond_signal(&rcu_worker_cond);
+		}
+	}
+}
+
+static void *rcu_worker(void *arg)
+{
+	struct rcu_head *r;
+
+	rcupdate_thread_init();
+
+	while (1) {
+		pthread_mutex_lock(&rculock);
+		while (!rcuhead_global) {
+			pthread_cond_wait(&rcu_worker_cond, &rculock);
+		}
+		r = rcuhead_global;
+		rcuhead_global = NULL;
+
+		pthread_mutex_unlock(&rculock);
+
+		synchronize_rcu();
+
+		while (r) {
+			struct rcu_head *tmp = r->next;
+			r->func(r);
+			r = tmp;
+		}
+	}
+
+	rcupdate_thread_exit();
+
+	return NULL;
+}
+
+static pthread_t worker_thread;
+void rcupdate_init(void)
+{
+	pthread_create(&worker_thread, NULL, rcu_worker, NULL);
+}
+
+void rcupdate_thread_init(void)
+{
+	rcu_register_thread();
+}
+void rcupdate_thread_exit(void)
+{
+	rcu_unregister_thread();
+}