On Fri, Nov 25, 2022 at 04:43:04PM +0800, David Gow wrote: > 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@xxxxxxxxxx> > Reviewed-by: Daniel Latypov <dlatypov@xxxxxxxxxx> > --- > 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 v3: > https://lore.kernel.org/linux-kselftest/20221119081252.3864249-1-davidgow@xxxxxxxxxx/ > - Use DECLARE_STATIC_KEY_FALSE() -- thanks Daniel! > > No changes since v2: > https://lore.kernel.org/all/20221025071907.1251820-1-davidgow@xxxxxxxxxx/ > > Changes since v1: > https://lore.kernel.org/linux-kselftest/20221021072854.333010-1-davidgow@xxxxxxxxxx/ > - 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(+) > > diff --git a/include/kunit/test.h b/include/kunit/test.h > index 4666a4d199ea..87ea90576b50 100644 > --- a/include/kunit/test.h > +++ b/include/kunit/test.h > @@ -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 */ > +DECLARE_STATIC_KEY_FALSE(kunit_running); > + > struct kunit; > > /* Size of log associated with test. */ > diff --git a/lib/kunit/test.c b/lib/kunit/test.c > index 1c9d8d962d67..87a5d795843b 100644 > --- a/lib/kunit/test.c > +++ b/lib/kunit/test.c > @@ -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. > @@ -615,10 +617,14 @@ int __kunit_test_suites_init(struct kunit_suite * const * const suites, int num_ > return 0; > } > > + static_branch_inc(&kunit_running); Is it expected there will be multiple tests running? (I was expecting "static_branch_enable"). > + > 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); > -- > 2.38.1.584.g0f3c55d4c2-goog > Regardless: Reviewed-by: Kees Cook <keescook@xxxxxxxxxxxx> -- Kees Cook
