Add a simple stress test for lib/ratelimit.c
To run on x86:
./tools/testing/kunit/kunit.py run --arch x86_64 --kconfig_add CONFIG_RATELIMIT_KUNIT_TEST=y --kconfig_add CONFIG_SMP=y --qemu_args "-smp 4" lib_ratelimit
On a 16-CPU system, the "4" in "-smp 4" can be varied between 1 and 8.
Larger numbers have higher probabilities of introducing delays that
break the smoke test. In the extreme case, increasing the number to
larger than the number of CPUs in the underlying system is an excellent
way to get a test failure.
Link: https://lore.kernel.org/all/fbe93a52-365e-47fe-93a4-44a44547d601@paulmck-laptop/
Link: https://lore.kernel.org/all/20250423115409.3425-1-spasswolf@web.de/
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Kuniyuki Iwashima <kuniyu@amazon.com>
Cc: Mateusz Guzik <mjguzik@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: John Ogness <john.ogness@linutronix.de>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Jon Pan-Doh <pandoh@google.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Karolina Stolarek <karolina.stolarek@oracle.com>
The selftest fails most of the times when running in qemu with
a kernel configured with CONFIG_HZ = 250:
> test_ratelimit_smoke: 1 callbacks suppressed
> # test_ratelimit_smoke: ASSERTION FAILED at lib/tests/test_ratelimit.c:28
> Expected ___ratelimit(&testrl, "test_ratelimit_smoke") == (false), but
> ___ratelimit(&testrl, "test_ratelimit_smoke") == 1 (0x1)
> (false) == 0 (0x0)
Try to make the test slightly more reliable by calling the problematic
ratelimit in the middle of the interval.
Signed-off-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Add a simple single-threaded smoke test for lib/ratelimit.c
To run on x86:
make ARCH=x86_64 mrproper
./tools/testing/kunit/kunit.py run --arch x86_64 --kconfig_add CONFIG_RATELIMIT_KUNIT_TEST=y --kconfig_add CONFIG_SMP=y lib_ratelimit
This will fail on old ___ratelimit(), and subsequent patches provide
the fixes that are required.
[ paulmck: Apply timeout and kunit feedback from Petr Mladek. ]
Link: https://lore.kernel.org/all/fbe93a52-365e-47fe-93a4-44a44547d601@paulmck-laptop/
Link: https://lore.kernel.org/all/20250423115409.3425-1-spasswolf@web.de/
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Kuniyuki Iwashima <kuniyu@amazon.com>
Cc: Mateusz Guzik <mjguzik@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: John Ogness <john.ogness@linutronix.de>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Jon Pan-Doh <pandoh@google.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Karolina Stolarek <karolina.stolarek@oracle.com>
