Commit 0561bd56 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge tag 'ratelimit.2025.07.23a' of... 

Merge tag 'ratelimit.2025.07.23a' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu

Pull ratelimit test updates from Paul McKenney:
 "Add functional and stress tests:

   - Add trivial kunit test for ratelimit

   - Make the ratelimit test more reliable (Petr Mladek)

   - Add stress test for ratelimit"

* tag 'ratelimit.2025.07.23a' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu:
  lib: Add stress test for ratelimit
  lib: Make the ratelimit test more reliable
  lib: Add trivial kunit test for ratelimit
parents 93942645 5c23ce0c

lib/Kconfig.debug

+11 −0
Original line number Diff line number Diff line
@@ -3214,6 +3214,17 @@ config TEST_OBJPOOL 


	  If unsure, say N.



config RATELIMIT_KUNIT_TEST

	tristate "KUnit Test for correctness and stress of ratelimit" if !KUNIT_ALL_TESTS

	depends on KUNIT

	default KUNIT_ALL_TESTS

	help

	  This builds the "test_ratelimit" module that should be used

	  for correctness verification and concurrent testings of rate

	  limiting.



	  If unsure, say N.



config INT_POW_KUNIT_TEST

	tristate "Integer exponentiation (int_pow) test" if !KUNIT_ALL_TESTS

	depends on KUNIT

lib/tests/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -46,5 +46,6 @@ obj-$(CONFIG_STRING_KUNIT_TEST) += string_kunit.o 
obj-$(CONFIG_STRING_HELPERS_KUNIT_TEST) += string_helpers_kunit.o

obj-$(CONFIG_USERCOPY_KUNIT_TEST) += usercopy_kunit.o

obj-$(CONFIG_UTIL_MACROS_KUNIT) += util_macros_kunit.o

obj-$(CONFIG_RATELIMIT_KUNIT_TEST) += test_ratelimit.o



obj-$(CONFIG_TEST_RUNTIME_MODULE)		+= module/

lib/tests/test_ratelimit.c

0 → 100644
+144 −0
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// SPDX-License-Identifier: GPL-2.0-only



#include <kunit/test.h>



#include <linux/ratelimit.h>

#include <linux/module.h>

#include <linux/kthread.h>

#include <linux/cpumask.h>



/* a simple boot-time regression test */



#define TESTRL_INTERVAL (5 * HZ)

static DEFINE_RATELIMIT_STATE(testrl, TESTRL_INTERVAL, 3);



#define test_ratelimited(test, expected) \

	KUNIT_ASSERT_EQ(test, ___ratelimit(&testrl, "test_ratelimit_smoke"), (expected))



static void test_ratelimit_smoke(struct kunit *test)

{

	// Check settings.

	KUNIT_ASSERT_GE(test, TESTRL_INTERVAL, 100);



	// Test normal operation.

	test_ratelimited(test, true);

	test_ratelimited(test, true);

	test_ratelimited(test, true);

	test_ratelimited(test, false);



	schedule_timeout_idle(TESTRL_INTERVAL / 2);

	test_ratelimited(test, false);



	schedule_timeout_idle(TESTRL_INTERVAL * 3 / 4);

	test_ratelimited(test, true);



	schedule_timeout_idle(2 * TESTRL_INTERVAL);

	test_ratelimited(test, true);

	test_ratelimited(test, true);



	schedule_timeout_idle(TESTRL_INTERVAL / 2 );

	test_ratelimited(test, true);

	schedule_timeout_idle(TESTRL_INTERVAL * 3 / 4);

	test_ratelimited(test, true);

	test_ratelimited(test, true);

	test_ratelimited(test, true);

	test_ratelimited(test, false);



	// Test disabling.

	testrl.burst = 0;

	test_ratelimited(test, false);

	testrl.burst = 2;

	testrl.interval = 0;

	test_ratelimited(test, true);

	test_ratelimited(test, true);

	test_ratelimited(test, true);

	test_ratelimited(test, true);

	test_ratelimited(test, true);

	test_ratelimited(test, true);

	test_ratelimited(test, true);



	// Testing re-enabling.

	testrl.interval = TESTRL_INTERVAL;

	test_ratelimited(test, true);

	test_ratelimited(test, true);

	test_ratelimited(test, false);

	test_ratelimited(test, false);

}



static struct ratelimit_state stressrl = RATELIMIT_STATE_INIT_FLAGS("stressrl", HZ / 10, 3,

								    RATELIMIT_MSG_ON_RELEASE);



static int doneflag;

static const int stress_duration = 2 * HZ;



struct stress_kthread {

	unsigned long nattempts;

	unsigned long nunlimited;

	unsigned long nlimited;

	unsigned long nmissed;

	struct task_struct *tp;

};



static int test_ratelimit_stress_child(void *arg)

{

	struct stress_kthread *sktp = arg;



	set_user_nice(current, MAX_NICE);

	WARN_ON_ONCE(!sktp->tp);



	while (!READ_ONCE(doneflag)) {

		sktp->nattempts++;

		if (___ratelimit(&stressrl, __func__))

			sktp->nunlimited++;

		else

			sktp->nlimited++;

		cond_resched();

	}



	sktp->nmissed = ratelimit_state_reset_miss(&stressrl);

	return 0;

}



static void test_ratelimit_stress(struct kunit *test)

{

	int i;

	const int n_stress_kthread = cpumask_weight(cpu_online_mask);

	struct stress_kthread skt = { 0 };

	struct stress_kthread *sktp = kcalloc(n_stress_kthread, sizeof(*sktp), GFP_KERNEL);



	KUNIT_EXPECT_NOT_NULL_MSG(test, sktp, "Memory allocation failure");

	for (i = 0; i < n_stress_kthread; i++) {

		sktp[i].tp = kthread_run(test_ratelimit_stress_child, &sktp[i], "%s/%i",

					 "test_ratelimit_stress_child", i);

		KUNIT_EXPECT_NOT_NULL_MSG(test, sktp, "kthread creation failure");

		pr_alert("Spawned test_ratelimit_stress_child %d\n", i);

	}

	schedule_timeout_idle(stress_duration);

	WRITE_ONCE(doneflag, 1);

	for (i = 0; i < n_stress_kthread; i++) {

		kthread_stop(sktp[i].tp);

		skt.nattempts += sktp[i].nattempts;

		skt.nunlimited += sktp[i].nunlimited;

		skt.nlimited += sktp[i].nlimited;

		skt.nmissed += sktp[i].nmissed;

	}

	KUNIT_ASSERT_EQ_MSG(test, skt.nunlimited + skt.nlimited, skt.nattempts,

			    "Outcomes not equal to attempts");

	KUNIT_ASSERT_EQ_MSG(test, skt.nlimited, skt.nmissed, "Misses not equal to limits");

}



static struct kunit_case ratelimit_test_cases[] = {

	KUNIT_CASE_SLOW(test_ratelimit_smoke),

	KUNIT_CASE_SLOW(test_ratelimit_stress),

	{}

};



static struct kunit_suite ratelimit_test_suite = {

	.name = "lib_ratelimit",

	.test_cases = ratelimit_test_cases,

};



kunit_test_suites(&ratelimit_test_suite);



MODULE_DESCRIPTION("___ratelimit() KUnit test suite");

MODULE_LICENSE("GPL");