selftests, sched/membarrier: Add multi-threaded test

membarrier commands cover very different code paths if they are in
a single-threaded vs multi-threaded process. Therefore, exercise both
scenarios in the kernel selftests to increase coverage of this selftest.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Chris Metcalf <cmetcalf@ezchip.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Kirill Tkhai <tkhai@yandex.ru>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Paul E. McKenney <paulmck@linux.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Russell King - ARM Linux admin <linux@armlinux.org.uk>
Cc: Shuah Khan <shuahkh@osg.samsung.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20190919173705.2181-6-mathieu.desnoyers@efficios.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

5 files changed, 124 insertions, 21 deletions

diff --git a/tools/testing/selftests/membarrier/.gitignore b/tools/testing/selftests/membarrier/.gitignore
index 020c44f49a9e..f2f7ec0a99b4 100644
--- a/tools/testing/selftests/membarrier/.gitignore
+++ b/tools/testing/selftests/membarrier/.gitignore
@@ -1 +1,2 @@
-membarrier_test
+membarrier_test_multi_thread
+membarrier_test_single_thread
diff --git a/tools/testing/selftests/membarrier/Makefile b/tools/testing/selftests/membarrier/Makefile
index 97e3bdf3d1e9..34d1c81a2324 100644
--- a/tools/testing/selftests/membarrier/Makefile
+++ b/tools/testing/selftests/membarrier/Makefile
@@ -1,7 +1,8 @@
 # SPDX-License-Identifier: GPL-2.0-only
 CFLAGS += -g -I../../../../usr/include/
+LDLIBS += -lpthread
 
-TEST_GEN_PROGS := membarrier_test
+TEST_GEN_PROGS := membarrier_test_single_thread \
+                membarrier_test_multi_thread
 
 include ../lib.mk
-
diff --git a/tools/testing/selftests/membarrier/membarrier_test.c b/tools/testing/selftests/membarrier/membarrier_test_impl.h
index 70b4ddbf126b..186be69f0a59 100644
--- a/tools/testing/selftests/membarrier/membarrier_test.c
+++ b/tools/testing/selftests/membarrier/membarrier_test_impl.h
@@ -1,10 +1,11 @@
-// SPDX-License-Identifier: GPL-2.0
+/* SPDX-License-Identifier: GPL-2.0 */
 #define _GNU_SOURCE
 #include <linux/membarrier.h>
 #include <syscall.h>
 #include <stdio.h>
 #include <errno.h>
 #include <string.h>
+#include <pthread.h>
 
 #include "../kselftest.h"
 
@@ -223,7 +224,7 @@ static int test_membarrier_global_expedited_success(void)
         return 0;
 }
 
-static int test_membarrier(void)
+static int test_membarrier_fail(void)
 {
         int status;
 
@@ -233,10 +234,27 @@ static int test_membarrier(void)
         status = test_membarrier_flags_fail();
         if (status)
                 return status;
-        status = test_membarrier_global_success();
+        status = test_membarrier_private_expedited_fail();
         if (status)
                 return status;
-        status = test_membarrier_private_expedited_fail();
+        status = sys_membarrier(MEMBARRIER_CMD_QUERY, 0);
+        if (status < 0) {
+                ksft_test_result_fail("sys_membarrier() failed\n");
+                return status;
+        }
+        if (status & MEMBARRIER_CMD_PRIVATE_EXPEDITED_SYNC_CORE) {
+                status = test_membarrier_private_expedited_sync_core_fail();
+                if (status)
+                        return status;
+        }
+        return 0;
+}
+
+static int test_membarrier_success(void)
+{
+        int status;
+
+        status = test_membarrier_global_success();
         if (status)
                 return status;
         status = test_membarrier_register_private_expedited_success();
@@ -251,9 +269,6 @@ static int test_membarrier(void)
                 return status;
         }
         if (status & MEMBARRIER_CMD_PRIVATE_EXPEDITED_SYNC_CORE) {
-                status = test_membarrier_private_expedited_sync_core_fail();
-                if (status)
-                        return status;
                 status = test_membarrier_register_private_expedited_sync_core_success();
                 if (status)
                         return status;
@@ -300,14 +315,3 @@ static int test_membarrier_query(void)
         ksft_test_result_pass("sys_membarrier available\n");
         return 0;
 }
-
-int main(int argc, char **argv)
-{
-        ksft_print_header();
-        ksft_set_plan(13);
-
-        test_membarrier_query();
-        test_membarrier();
-
-        return ksft_exit_pass();
-}
diff --git a/tools/testing/selftests/membarrier/membarrier_test_multi_thread.c b/tools/testing/selftests/membarrier/membarrier_test_multi_thread.c
new file mode 100644
index 000000000000..ac5613e5b0eb
--- /dev/null
+++ b/tools/testing/selftests/membarrier/membarrier_test_multi_thread.c
@@ -0,0 +1,73 @@
+// SPDX-License-Identifier: GPL-2.0
+#define _GNU_SOURCE
+#include <linux/membarrier.h>
+#include <syscall.h>
+#include <stdio.h>
+#include <errno.h>
+#include <string.h>
+#include <pthread.h>
+
+#include "membarrier_test_impl.h"
+
+static int thread_ready, thread_quit;
+static pthread_mutex_t test_membarrier_thread_mutex =
+        PTHREAD_MUTEX_INITIALIZER;
+static pthread_cond_t test_membarrier_thread_cond =
+        PTHREAD_COND_INITIALIZER;
+
+void *test_membarrier_thread(void *arg)
+{
+        pthread_mutex_lock(&test_membarrier_thread_mutex);
+        thread_ready = 1;
+        pthread_cond_broadcast(&test_membarrier_thread_cond);
+        pthread_mutex_unlock(&test_membarrier_thread_mutex);
+
+        pthread_mutex_lock(&test_membarrier_thread_mutex);
+        while (!thread_quit)
+                pthread_cond_wait(&test_membarrier_thread_cond,
+                                  &test_membarrier_thread_mutex);
+        pthread_mutex_unlock(&test_membarrier_thread_mutex);
+
+        return NULL;
+}
+
+static int test_mt_membarrier(void)
+{
+        int i;
+        pthread_t test_thread;
+
+        pthread_create(&test_thread, NULL,
+                       test_membarrier_thread, NULL);
+
+        pthread_mutex_lock(&test_membarrier_thread_mutex);
+        while (!thread_ready)
+                pthread_cond_wait(&test_membarrier_thread_cond,
+                                  &test_membarrier_thread_mutex);
+        pthread_mutex_unlock(&test_membarrier_thread_mutex);
+
+        test_membarrier_fail();
+
+        test_membarrier_success();
+
+        pthread_mutex_lock(&test_membarrier_thread_mutex);
+        thread_quit = 1;
+        pthread_cond_broadcast(&test_membarrier_thread_cond);
+        pthread_mutex_unlock(&test_membarrier_thread_mutex);
+
+        pthread_join(test_thread, NULL);
+
+        return 0;
+}
+
+int main(int argc, char **argv)
+{
+        ksft_print_header();
+        ksft_set_plan(13);
+
+        test_membarrier_query();
+
+        /* Multi-threaded */
+        test_mt_membarrier();
+
+        return ksft_exit_pass();
+}
diff --git a/tools/testing/selftests/membarrier/membarrier_test_single_thread.c b/tools/testing/selftests/membarrier/membarrier_test_single_thread.c
new file mode 100644
index 000000000000..c1c963902854
--- /dev/null
+++ b/tools/testing/selftests/membarrier/membarrier_test_single_thread.c
@@ -0,0 +1,24 @@
+// SPDX-License-Identifier: GPL-2.0
+#define _GNU_SOURCE
+#include <linux/membarrier.h>
+#include <syscall.h>
+#include <stdio.h>
+#include <errno.h>
+#include <string.h>
+#include <pthread.h>
+
+#include "membarrier_test_impl.h"
+
+int main(int argc, char **argv)
+{
+        ksft_print_header();
+        ksft_set_plan(13);
+
+        test_membarrier_query();
+
+        test_membarrier_fail();
+
+        test_membarrier_success();
+
+        return ksft_exit_pass();
+}