@@ -16,6 +16,7 @@
#include <linux/container_of.h>
#include <linux/err.h>
#include <linux/init.h>
+#include <linux/jump_label.h>
#include <linux/kconfig.h>
#include <linux/kref.h>
#include <linux/list.h>
@@ -27,6 +28,9 @@
#include <asm/rwonce.h>
+/* Static key: true if any KUnit tests are currently running */
+extern struct static_key_false kunit_running;
+
struct kunit;
/* Size of log associated with test. */
@@ -20,6 +20,8 @@
#include "string-stream.h"
#include "try-catch-impl.h"
+DEFINE_STATIC_KEY_FALSE(kunit_running);
+
#if IS_BUILTIN(CONFIG_KUNIT)
/*
* Fail the current test and print an error message to the log.
@@ -612,10 +614,14 @@ int __kunit_test_suites_init(struct kunit_suite * const * const suites, int num_
return 0;
}
+ static_branch_inc(&kunit_running);
+
for (i = 0; i < num_suites; i++) {
kunit_init_suite(suites[i]);
kunit_run_tests(suites[i]);
}
+
+ static_branch_dec(&kunit_running);
return 0;
}
EXPORT_SYMBOL_GPL(__kunit_test_suites_init);
KUnit does a few expensive things when enabled. This hasn't been a problem because KUnit was only enabled on test kernels, but with a few people enabling (but not _using_) KUnit on production systems, we need a runtime way of handling this. Provide a 'kunit_running' static key (defaulting to false), which allows us to hide any KUnit code behind a static branch. This should reduce the performance impact (on other code) of having KUnit enabled to a single NOP when no tests are running. Note that, while it looks unintuitive, tests always run entirely within __kunit_test_suites_init(), so it's safe to decrement the static key at the end of this function, rather than in __kunit_test_suites_exit(), which is only there to clean up results in debugfs. Signed-off-by: David Gow <davidgow@google.com> --- This should be a no-op (other than a possible performance improvement) functionality-wise, and lays the groundwork for a more optimised static stub implementation. The remaining patches in the series add a kunit_get_current_test() function which is a more friendly and performant wrapper around current->kunit_test, and use this in the slub test. They also improve the documentation a bit. If there are no objections, we'll take the whole series via the KUnit tree. Changes since v1: https://lore.kernel.org/linux-kselftest/20221021072854.333010-1-davidgow@google.com/ - No changes in this patch. - Patch 2/3 is reworked, patch 3/3 is new. --- include/kunit/test.h | 4 ++++ lib/kunit/test.c | 6 ++++++ 2 files changed, 10 insertions(+)