From 1366c37ed84b166a0fffe201154b0d3b78a3976b Mon Sep 17 00:00:00 2001
From: Matthew Wilcox <willy@linux.intel.com>
Date: Thu, 17 Mar 2016 14:21:45 -0700
Subject: radix tree test harness

This code is mostly from Andrew Morton and Nick Piggin; tarball downloaded
from http://ozlabs.org/~akpm/rtth.tar.gz with sha1sum
0ce679db9ec047296b5d1ff7a1dfaa03a7bef1bd

Some small modifications were necessary to the test harness to fix the
build with the current Linux source code.

I also made minor modifications to automatically test the radix-tree.c
and radix-tree.h files that are in the current source tree, as opposed
to a copied and slightly modified version.  I am sure more could be done
to tidy up the harness, as well as adding more tests.

[koct9i@gmail.com: fix compilation]
Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
Cc: Shuah Khan <shuahkh@osg.samsung.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Matthew Wilcox <willy@linux.intel.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Konstantin Khlebnikov <koct9i@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
 tools/testing/radix-tree/rcupdate.c | 86 +++++++++++++++++++++++++++++++++++++
 1 file changed, 86 insertions(+)
 create mode 100644 tools/testing/radix-tree/rcupdate.c

(limited to 'tools/testing/radix-tree/rcupdate.c')

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();
+}
-- 
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