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Message-Id: <20161201114711.28697-4-chris@chris-wilson.co.uk>
Date: Thu, 1 Dec 2016 11:47:06 +0000
From: Chris Wilson <chris@...is-wilson.co.uk>
To: linux-kernel@...r.kernel.org
Cc: Chris Wilson <chris@...is-wilson.co.uk>,
Peter Zijlstra <peterz@...radead.org>,
Ingo Molnar <mingo@...hat.com>,
Maarten Lankhorst <dev@...ankhorst.nl>,
Nicolai Hähnle <nhaehnle@...il.com>
Subject: [PATCH v2 3/8] locking: Begin kselftests for ww_mutex
v2: Add a couple more variations for degenerate ww_mutex, decrease
timeouts
Signed-off-by: Chris Wilson <chris@...is-wilson.co.uk>
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: Ingo Molnar <mingo@...hat.com>
Cc: Maarten Lankhorst <dev@...ankhorst.nl>
Cc: Nicolai Hähnle <nhaehnle@...il.com>
---
kernel/locking/Makefile | 1 +
kernel/locking/test-ww_mutex.c | 140 +++++++++++++++++++++++++++++++++++++++++
lib/Kconfig.debug | 12 ++++
3 files changed, 153 insertions(+)
create mode 100644 kernel/locking/test-ww_mutex.c
diff --git a/kernel/locking/Makefile b/kernel/locking/Makefile
index 6f88e352cd4f..760158d9d98d 100644
--- a/kernel/locking/Makefile
+++ b/kernel/locking/Makefile
@@ -28,3 +28,4 @@ obj-$(CONFIG_RWSEM_GENERIC_SPINLOCK) += rwsem-spinlock.o
obj-$(CONFIG_RWSEM_XCHGADD_ALGORITHM) += rwsem-xadd.o
obj-$(CONFIG_QUEUED_RWLOCKS) += qrwlock.o
obj-$(CONFIG_LOCK_TORTURE_TEST) += locktorture.o
+obj-$(CONFIG_WW_MUTEX_SELFTEST) += test-ww_mutex.o
diff --git a/kernel/locking/test-ww_mutex.c b/kernel/locking/test-ww_mutex.c
new file mode 100644
index 000000000000..472d5b1f303f
--- /dev/null
+++ b/kernel/locking/test-ww_mutex.c
@@ -0,0 +1,140 @@
+/*
+ * Module-based API test facility for ww_mutexes
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, you can access it online at
+ * http://www.gnu.org/licenses/gpl-2.0.html.
+ */
+
+#include <linux/kernel.h>
+
+#include <linux/completion.h>
+#include <linux/kthread.h>
+#include <linux/module.h>
+#include <linux/ww_mutex.h>
+
+static DEFINE_WW_CLASS(ww_class);
+
+struct test_mutex {
+ struct work_struct work;
+ struct ww_mutex mutex;
+ struct completion ready, go, done;
+ unsigned int flags;
+};
+
+#define TEST_MTX_SPIN BIT(0)
+#define TEST_MTX_TRY BIT(1)
+#define TEST_MTX_CTX BIT(2)
+#define __TEST_MTX_LAST BIT(3)
+
+static void test_mutex_work(struct work_struct *work)
+{
+ struct test_mutex *mtx = container_of(work, typeof(*mtx), work);
+
+ complete(&mtx->ready);
+ wait_for_completion(&mtx->go);
+
+ if (mtx->flags & TEST_MTX_TRY) {
+ while (!ww_mutex_trylock(&mtx->mutex))
+ cpu_relax();
+ } else {
+ ww_mutex_lock(&mtx->mutex, NULL);
+ }
+ complete(&mtx->done);
+ ww_mutex_unlock(&mtx->mutex);
+}
+
+static int __test_mutex(unsigned int flags)
+{
+#define TIMEOUT (HZ / 16)
+ struct test_mutex mtx;
+ struct ww_acquire_ctx ctx;
+ int ret;
+
+ ww_mutex_init(&mtx.mutex, &ww_class);
+ ww_acquire_init(&ctx, &ww_class);
+
+ INIT_WORK_ONSTACK(&mtx.work, test_mutex_work);
+ init_completion(&mtx.ready);
+ init_completion(&mtx.go);
+ init_completion(&mtx.done);
+ mtx.flags = flags;
+
+ schedule_work(&mtx.work);
+
+ wait_for_completion(&mtx.ready);
+ ww_mutex_lock(&mtx.mutex, (flags & TEST_MTX_CTX) ? &ctx : NULL);
+ complete(&mtx.go);
+ if (flags & TEST_MTX_SPIN) {
+ unsigned long timeout = jiffies + TIMEOUT;
+
+ ret = 0;
+ do {
+ if (completion_done(&mtx.done)) {
+ ret = -EINVAL;
+ break;
+ }
+ cpu_relax();
+ } while (time_before(jiffies, timeout));
+ } else {
+ ret = wait_for_completion_timeout(&mtx.done, TIMEOUT);
+ }
+ ww_mutex_unlock(&mtx.mutex);
+ ww_acquire_fini(&ctx);
+
+ if (ret) {
+ pr_err("%s(flags=%x): mutual exclusion failure\n",
+ __func__, flags);
+ ret = -EINVAL;
+ }
+
+ flush_work(&mtx.work);
+ destroy_work_on_stack(&mtx.work);
+ return ret;
+#undef TIMEOUT
+}
+
+static int test_mutex(void)
+{
+ int ret;
+ int i;
+
+ for (i = 0; i < __TEST_MTX_LAST; i++) {
+ ret = __test_mutex(i);
+ if (ret)
+ return ret;
+ }
+
+ return 0;
+}
+
+static int __init test_ww_mutex_init(void)
+{
+ int ret;
+
+ ret = test_mutex();
+ if (ret)
+ return ret;
+
+ return 0;
+}
+
+static void __exit test_ww_mutex_exit(void)
+{
+}
+
+module_init(test_ww_mutex_init);
+module_exit(test_ww_mutex_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Intel Corporation");
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index a6c8db1d62f6..cf8f3e942b46 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -1161,6 +1161,18 @@ config LOCK_TORTURE_TEST
Say M if you want these torture tests to build as a module.
Say N if you are unsure.
+config WW_MUTEX_SELFTEST
+ tristate "Wait/wound mutex selftests"
+ help
+ This option provides a kernel module that runs tests on the
+ on the struct ww_mutex locking API.
+
+ It is recommended to enable DEBUG_WW_MUTEX_SLOWPATH in conjunction
+ with this test harness.
+
+ Say M if you want these self tests to build as a module.
+ Say N if you are unsure.
+
endmenu # lock debugging
config TRACE_IRQFLAGS
--
2.10.2
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