Re: [v2,05/12] rcutorture: Add tests for SRCU up/down reader primitives

Joel Fernandes
2025-04-08T22:05:23Z

On 4/8/2025 4:58 PM, Paul E. McKenney wrote:
> On Tue, Apr 08, 2025 at 08:18:05PM -0000, Joel Fernandes wrote:
>> Hello, Paul,
>>
>> On Tue, 8 Apr 2025 20:16:08 GMT, "Paul E. McKenney" wrote:
>>> This commit adds a new rcutorture.n_up_down kernel boot parameter
>>> that specifies the number of outstanding SRCU up/down readers, which
>>> begin in kthread context and end in an hrtimer handler. There is a new
>>> kthread ("rcu_torture_updown") that scans an per-reader array looking
>>> for elements whose readers have ended. This kthread sleeps between one
>>> and two milliseconds between consecutive scans.
>>>
>>> [ paulmck: Apply kernel test robot feedback. ]
>>> [ paulmck: Apply Z qiang feedback. ]
>>>
>> [...]
>>> + for (i = 0; i < n_up_down; i++) {
>>> + init_rcu_torture_one_read_state(&updownreaders[i].rtorsu_rtors, rand);
>>> + hrtimer_init(&updownreaders[i].rtorsu_hrt, CLOCK_MONOTONIC,
>>> + HRTIMER_MODE_REL | HRTIMER_MODE_SOFT);
>>
>> This will now fail to build and needs the following: I will squash it into my
>> for-next branch into this patch, but let me know if you prefer to provide an
>> update.
>
> Please feel free to squash it in with your "[]" tag like shown above.

Yep done already. :-)

>
> As you say, you will be sending them all out soon enough anyway. ;-)

True. ;-)

>
> My plan is to rebase on your stack once you finish your first long-form
> round of testing.

Perfect, my first long-form test should be done by tomorrow AM.

- Joel

>
> Thanx, Paul
>
>> Fix build error by converting hrtimer_init to hrtimer_setup, see:
>> https://lore.kernel.org/all/174384280127.31282.2714486346304643188.tip-bot2@tip-bot2/
>>
>> diff --git a/kernel/rcu/rcutorture.c b/kernel/rcu/rcutorture.c
>> index 4f0a00a8bdee..14a22ef3b56f 100644
>> --- a/kernel/rcu/rcutorture.c
>> +++ b/kernel/rcu/rcutorture.c
>> @@ -2480,9 +2480,8 @@ static int rcu_torture_updown_init(void)
>> }
>> for (i = 0; i < n_up_down; i++) {
>> init_rcu_torture_one_read_state(&updownreaders[i].rtorsu_rtors, rand);
>> - hrtimer_init(&updownreaders[i].rtorsu_hrt, CLOCK_MONOTONIC,
>> - HRTIMER_MODE_REL | HRTIMER_MODE_SOFT);
>> - updownreaders[i].rtorsu_hrt.function = rcu_torture_updown_hrt;
>> + hrtimer_setup(&updownreaders[i].rtorsu_hrt,
>> rcu_torture_updown_hrt, CLOCK_MONOTONIC,
>> + HRTIMER_MODE_REL | HRTIMER_MODE_SOFT);
>> torture_random_init(&updownreaders[i].rtorsu_trs);
>> init_rcu_torture_one_read_state(&updownreaders[i].rtorsu_rtors,
>> &updownreaders[i].rtorsu_trs);
>>
>> Thanks.