On Wed, Feb 17, 2021 at 07:51:10PM +0100, Uladzislau Rezki (Sony) wrote:
> To stress and test a single argument of kfree_rcu() call, we
> should to have a special coverage for it. We used to have it
> in the test-suite related to vmalloc stressing. The reason is
> the rcuscale is a correct place for RCU related things.
>
> Therefore introduce two torture_param() variables, one is for
> single-argument scale test and another one for double-argument
> scale test.
>
> By default kfree_rcu_test_single and kfree_rcu_test_double are
> initialized to false. If both have the same value (false or true)
> both are randomly tested, otherwise only the one with value true
> is tested. The value of this is that it allows testing of both
> options with one test.
>
> Suggested-by: Paul E. McKenney <paulmck@xxxxxxxxxx>
> Signed-off-by: Uladzislau Rezki (Sony) <urezki@xxxxxxxxx>
Queued with the usual wordsmithing, thank you!
Thanx, Paul
> ---
> kernel/rcu/rcuscale.c | 15 ++++++++++++++-
> 1 file changed, 14 insertions(+), 1 deletion(-)
>
> diff --git a/kernel/rcu/rcuscale.c b/kernel/rcu/rcuscale.c
> index 06491d5530db..0fb540e2b22b 100644
> --- a/kernel/rcu/rcuscale.c
> +++ b/kernel/rcu/rcuscale.c
> @@ -625,6 +625,8 @@ rcu_scale_shutdown(void *arg)
> torture_param(int, kfree_nthreads, -1, "Number of threads running loops of kfree_rcu().");
> torture_param(int, kfree_alloc_num, 8000, "Number of allocations and frees done in an iteration.");
> torture_param(int, kfree_loops, 10, "Number of loops doing kfree_alloc_num allocations and frees.");
> +torture_param(bool, kfree_rcu_test_single, false, "Do we run a kfree_rcu() single-argument scale test?");
> +torture_param(bool, kfree_rcu_test_double, false, "Do we run a kfree_rcu() double-argument scale test?");
>
> static struct task_struct **kfree_reader_tasks;
> static int kfree_nrealthreads;
> @@ -644,10 +646,13 @@ kfree_scale_thread(void *arg)
> struct kfree_obj *alloc_ptr;
> u64 start_time, end_time;
> long long mem_begin, mem_during = 0;
> + bool kfree_rcu_test_both;
> + DEFINE_TORTURE_RANDOM(tr);
>
> VERBOSE_SCALEOUT_STRING("kfree_scale_thread task started");
> set_cpus_allowed_ptr(current, cpumask_of(me % nr_cpu_ids));
> set_user_nice(current, MAX_NICE);
> + kfree_rcu_test_both = (kfree_rcu_test_single == kfree_rcu_test_double);
>
> start_time = ktime_get_mono_fast_ns();
>
> @@ -670,7 +675,15 @@ kfree_scale_thread(void *arg)
> if (!alloc_ptr)
> return -ENOMEM;
>
> - kfree_rcu(alloc_ptr, rh);
> + // By default kfree_rcu_test_single and kfree_rcu_test_double are
> + // initialized to false. If both have the same value (false or true)
> + // both are randomly tested, otherwise only the one with value true
> + // is tested.
> + if ((kfree_rcu_test_single && !kfree_rcu_test_double) ||
> + (kfree_rcu_test_both && torture_random(&tr) & 0x800))
> + kfree_rcu(alloc_ptr);
> + else
> + kfree_rcu(alloc_ptr, rh);
> }
>
> cond_resched();
> --
> 2.20.1
>
