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>

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();
+}