[PATCH v3 04/33] radix tree test suite: Track preempt_count

Matthew Wilcox
2016-11-28T20:08:31Z

From: Matthew Wilcox <willy@infradead.org>

Rather than simply NOP out preempt_enable() and preempt_disable(),
keep track of preempt_count and display it regularly in case either
the test suite or the code under test is forgetting to balance the
enables & disables. Only found a test-case that was forgetting to
re-enable preemption, but it's a possibility worth checking.

Signed-off-by: Matthew Wilcox <willy@infradead.org>
---
tools/testing/radix-tree/linux.c | 1 +
tools/testing/radix-tree/linux/preempt.h | 6 +++---
tools/testing/radix-tree/main.c | 30 ++++++++++++++++++++----------
3 files changed, 24 insertions(+), 13 deletions(-)

diff --git a/tools/testing/radix-tree/linux.c b/tools/testing/radix-tree/linux.c
index 3cfb04e..1f32a16 100644
--- a/tools/testing/radix-tree/linux.c
+++ b/tools/testing/radix-tree/linux.c
@@ -9,6 +9,7 @@
#include <urcu/uatomic.h>

int nr_allocated;
+int preempt_count;

void *mempool_alloc(mempool_t *pool, int gfp_mask)
{
diff --git a/tools/testing/radix-tree/linux/preempt.h b/tools/testing/radix-tree/linux/preempt.h
index 6210672..65c04c2 100644
--- a/tools/testing/radix-tree/linux/preempt.h
+++ b/tools/testing/radix-tree/linux/preempt.h
@@ -1,4 +1,4 @@
-/* */
+extern int preempt_count;

-#define preempt_disable() do { } while (0)
-#define preempt_enable() do { } while (0)
+#define preempt_disable() uatomic_inc(&preempt_count)
+#define preempt_enable() uatomic_dec(&preempt_count)
diff --git a/tools/testing/radix-tree/main.c b/tools/testing/radix-tree/main.c
index daa9010..64ffe67 100644
--- a/tools/testing/radix-tree/main.c
+++ b/tools/testing/radix-tree/main.c
@@ -293,27 +293,36 @@ static void single_thread_tests(bool long_run)
{
int i;

- printf("starting single_thread_tests: %d allocated\n", nr_allocated);
+ printf("starting single_thread_tests: %d allocated, preempt %d\n",
+ nr_allocated, preempt_count);
multiorder_checks();
- printf("after multiorder_check: %d allocated\n", nr_allocated);
+ printf("after multiorder_check: %d allocated, preempt %d\n",
+ nr_allocated, preempt_count);
locate_check();
- printf("after locate_check: %d allocated\n", nr_allocated);
+ printf("after locate_check: %d allocated, preempt %d\n",
+ nr_allocated, preempt_count);
tag_check();
- printf("after tag_check: %d allocated\n", nr_allocated);
+ printf("after tag_check: %d allocated, preempt %d\n",
+ nr_allocated, preempt_count);
gang_check();
- printf("after gang_check: %d allocated\n", nr_allocated);
+ printf("after gang_check: %d allocated, preempt %d\n",
+ nr_allocated, preempt_count);
add_and_check();
- printf("after add_and_check: %d allocated\n", nr_allocated);
+ printf("after add_and_check: %d allocated, preempt %d\n",
+ nr_allocated, preempt_count);
dynamic_height_check();
- printf("after dynamic_height_check: %d allocated\n", nr_allocated);
+ printf("after dynamic_height_check: %d allocated, preempt %d\n",
+ nr_allocated, preempt_count);
big_gang_check(long_run);
- printf("after big_gang_check: %d allocated\n", nr_allocated);
+ printf("after big_gang_check: %d allocated, preempt %d\n",
+ nr_allocated, preempt_count);
for (i = 0; i < (long_run ? 2000 : 3); i++) {
copy_tag_check();
printf("%d ", i);
fflush(stdout);
}
- printf("after copy_tag_check: %d allocated\n", nr_allocated);
+ printf("after copy_tag_check: %d allocated, preempt %d\n",
+ nr_allocated, preempt_count);
}

int main(int argc, char **argv)
@@ -336,7 +345,8 @@ int main(int argc, char **argv)
single_thread_tests(long_run);

sleep(1);
- printf("after sleep(1): %d allocated\n", nr_allocated);
+ printf("after sleep(1): %d allocated, preempt %d\n",
+ nr_allocated, preempt_count);
rcu_unregister_thread();

exit(0);
--
2.10.2