pthread_mutex1: Enable contention on a shared pthread_mutex across pr…

tests/pthread_mutex1.c

@@ -1,15 +1,60 @@
 #define _GNU_SOURCE
 #include <pthread.h>
+#include <sys/mman.h>
+#include <assert.h>
 
 char *testcase_description = "Contended pthread mutex";
 
+#ifdef THREADS
 pthread_mutex_t mutex = PTHREAD_MUTEX_INITIALIZER;
+pthread_mutex_t pmutex = &mutex;
+#else
+static pthread_mutex_t *pmutex = NULL;
+
+/*
+ * Alloc a shared memory where it is placing a cross-process
+ * pthread mutex for verifying its scability of multi-process
+ */
+void testcase_prepare(unsigned long nr_tasks)
+{
+	int ret;
+	void *addr;
+
+	addr = mmap(NULL, sizeof(pthread_mutex_t),
+				PROT_READ | PROT_WRITE,
+				MAP_SHARED | MAP_ANONYMOUS, -1, 0);
+	assert(addr != MAP_FAILED);
+
+	pmutex = (pthread_mutex_t *)addr;
+
+	pthread_mutexattr_t attr;
+	ret = pthread_mutexattr_init(&attr);
+	assert(ret == 0);
+
+	ret = pthread_mutexattr_setpshared(&attr, PTHREAD_PROCESS_SHARED);
+	assert(ret == 0);
+
+	ret = pthread_mutex_init(pmutex, &attr);
+	assert(ret == 0);
+
+	pthread_mutexattr_destroy(&attr);
+}
+
+void testcase_cleanup(void)
+{
+	if (pmutex) {
+		pthread_mutex_destroy(pmutex);
+		munmap(pmutex, sizeof(pthread_mutex_t));
+	}
+}
+
+#endif
 
 void testcase(unsigned long long *iterations, unsigned long nr)
 {
 	while (1) {
-		pthread_mutex_lock(&mutex);
-		pthread_mutex_unlock(&mutex);
+		pthread_mutex_lock(pmutex);
+		pthread_mutex_unlock(pmutex);
 
 		(*iterations)++;
 	}