From: Joel Fernandes <joel@joelfernandes.org>
To: paulmck@kernel.org
Cc: rcu <rcu@vger.kernel.org>, LKML <linux-kernel@vger.kernel.org>,
Rushikesh S Kadam <rushikesh.s.kadam@intel.com>,
"Uladzislau Rezki (Sony)" <urezki@gmail.com>,
Neeraj upadhyay <neeraj.iitr10@gmail.com>,
Frederic Weisbecker <frederic@kernel.org>,
Steven Rostedt <rostedt@goodmis.org>,
vineeth@bitbyteword.org
Subject: Re: [PATCH v2 6/8] rcuscale: Add test for using call_rcu_lazy() to emulate kfree_rcu()
Date: Tue, 12 Jul 2022 17:15:23 -0400 [thread overview]
Message-ID: <dc5b3c63-7c95-79aa-75ec-1e8d1b3315f1@joelfernandes.org> (raw)
In-Reply-To: <20220712205854.GE1790663@paulmck-ThinkPad-P17-Gen-1>
On 7/12/2022 4:58 PM, Paul E. McKenney wrote:
> On Tue, Jul 12, 2022 at 04:27:05PM -0400, Joel Fernandes wrote:
>> Ah, with all the threads, I missed this one :(. Sorry about that.
>
> I know that feeling...
>
>> On Fri, Jul 8, 2022 at 7:06 PM Paul E. McKenney <paulmck@kernel.org> wrote:
>>
>>>> Currently I added a test like the following which adds a new torture type, my
>>>> thought was to stress the new code to make sure nothing crashed or hung the
>>>> kernel. That is working well except I don't exactly understand the total-gps
>>>> print showing 0, which the other print shows 1188 GPs. I'll go dig into that
>>>> tomorrow.. thanks!
>>>>
>>>> The print shows
>>>> TREE11 ------- 1474 GPs (12.2833/s) [rcu_lazy: g0 f0x0 total-gps=0]
>>>> TREE11 no success message, 7 successful version messages
>>>
>>> Nice!!! It is very good to see you correctly using the rcu_torture_ops
>>> facility correctly!
>>>
>>> And this could be good for your own testing, and I am happy to pull it
>>> in for that purpose (given it being fixed, having a good commit log,
>>> and so on). After all, TREE10 is quite similar -- not part of CFLIST,
>>> but useful for certain types of focused testing.
>>>
>>> However, it would be very good to get call_rcu_lazy() testing going
>>> more generally, and in particular in TREE01 where offloading changes
>>> dynamically. A good way to do this is to add a .call_lazy() component
>>> to the rcu_torture_ops structure, and check for it in a manner similar
>>> to that done for the .deferred_free() component. Including adding a
>>> gp_normal_lazy module parameter. This would allow habitual testing
>>> on a few scenarios and focused lazy testing on all of them via the
>>> --bootargs parameter.
>>
>> Ok, if you don't mind I will make this particular enhancement to the
>> torture test in a future patchset, since I kind of decided on doing v3
>> with just fixes to what I have and more testing. Certainly happy to
>> enhance these tests in a future version.
>
> No need to gate v3 on those tests.
>
>>> On the total-gps=0, the usual suspicion would be that the lazy callbacks
>>> never got invoked. It looks like you were doing about a two-minute run,
>>> so maybe a longer run? Though weren't they supposed to kick in at 15
>>> seconds or so? Or did this value of zero come about because this run
>>> used exactly 300 grace periods?
>>
>> It was zero because it required the RCU_FLAVOR torture type, where as
>> my torture type was lazy. Adding RCU_LAZY_FLAVOR to the list fixed it
>> :)
>
> Heh! Then it didn't actually do any testing. Done that as well!
Sorry to not be clear, I meant the switch-case list below, not the
torture list in rcutorture.c! It was in the rcutorture.c so was being
tested, just reporting zero gp_seq as I pointed.
/*
* Send along grace-period-related data for rcutorture diagnostics.
*/
void rcutorture_get_gp_data(enum rcutorture_type test_type, int *flags,
unsigned long *gp_seq)
{
switch (test_type) {
case RCU_FLAVOR:
case RCU_LAZY_FLAVOR:
*flags = READ_ONCE(rcu_state.gp_flags);
*gp_seq = rcu_seq_current(&rcu_state.gp_seq);
break;
default:
break;
}
}
EXPORT_SYMBOL_GPL(rcutorture_get_gp_data);
next prev parent reply other threads:[~2022-07-12 21:15 UTC|newest]
Thread overview: 60+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-06-22 22:50 [PATCH v2 0/8] Implement call_rcu_lazy() and miscellaneous fixes Joel Fernandes (Google)
2022-06-22 22:50 ` [PATCH v2 1/1] context_tracking: Use arch_atomic_read() in __ct_state for KASAN Joel Fernandes (Google)
2022-06-22 22:58 ` Joel Fernandes
2022-06-22 22:50 ` [PATCH v2 1/8] rcu: Introduce call_rcu_lazy() API implementation Joel Fernandes (Google)
2022-06-22 23:18 ` Joel Fernandes
2022-06-26 4:00 ` Paul E. McKenney
2022-06-23 1:38 ` kernel test robot
2022-06-26 4:00 ` Paul E. McKenney
2022-07-08 18:43 ` Joel Fernandes
2022-07-08 23:10 ` Paul E. McKenney
2022-07-10 2:26 ` Joel Fernandes
2022-07-10 16:03 ` Paul E. McKenney
2022-07-12 20:53 ` Joel Fernandes
2022-07-12 21:04 ` Paul E. McKenney
2022-07-12 21:10 ` Joel Fernandes
2022-07-12 22:41 ` Paul E. McKenney
2022-06-29 11:53 ` Frederic Weisbecker
2022-06-29 17:05 ` Paul E. McKenney
2022-06-29 20:29 ` Joel Fernandes
2022-06-29 22:01 ` Frederic Weisbecker
2022-06-30 14:08 ` Joel Fernandes
2022-06-22 22:50 ` [PATCH v2 2/8] rcu: shrinker for lazy rcu Joel Fernandes (Google)
2022-06-22 22:50 ` [PATCH v2 3/8] fs: Move call_rcu() to call_rcu_lazy() in some paths Joel Fernandes (Google)
2022-06-22 22:50 ` [PATCH v2 4/8] rcu/nocb: Add option to force all call_rcu() to lazy Joel Fernandes (Google)
2022-06-22 22:50 ` [PATCH v2 5/8] rcu/nocb: Wake up gp thread when flushing Joel Fernandes (Google)
2022-06-26 4:06 ` Paul E. McKenney
2022-06-26 13:45 ` Joel Fernandes
2022-06-26 13:52 ` Paul E. McKenney
2022-06-26 14:37 ` Joel Fernandes
2022-06-22 22:51 ` [PATCH v2 6/8] rcuscale: Add test for using call_rcu_lazy() to emulate kfree_rcu() Joel Fernandes (Google)
2022-06-23 2:09 ` kernel test robot
2022-06-23 3:00 ` kernel test robot
2022-06-23 8:10 ` kernel test robot
2022-06-26 4:13 ` Paul E. McKenney
2022-07-08 4:25 ` Joel Fernandes
2022-07-08 23:06 ` Paul E. McKenney
2022-07-12 20:27 ` Joel Fernandes
2022-07-12 20:58 ` Paul E. McKenney
2022-07-12 21:15 ` Joel Fernandes [this message]
2022-07-12 22:41 ` Paul E. McKenney
2022-06-22 22:51 ` [PATCH v2 7/8] rcu/nocb: Rewrite deferred wake up logic to be more clean Joel Fernandes (Google)
2022-06-22 22:51 ` [PATCH v2 8/8] rcu/kfree: Fix kfree_rcu_shrink_count() return value Joel Fernandes (Google)
2022-06-26 4:17 ` Paul E. McKenney
2022-06-27 18:56 ` Uladzislau Rezki
2022-06-27 20:59 ` Paul E. McKenney
2022-06-27 21:18 ` Joel Fernandes
2022-06-27 21:43 ` Paul E. McKenney
2022-06-28 16:56 ` Joel Fernandes
2022-06-28 21:13 ` Joel Fernandes
2022-06-29 16:56 ` Paul E. McKenney
2022-06-29 19:47 ` Joel Fernandes
2022-06-29 21:07 ` Paul E. McKenney
2022-06-30 14:25 ` Joel Fernandes
2022-06-30 15:29 ` Paul E. McKenney
2022-06-29 16:52 ` Paul E. McKenney
2022-06-26 3:12 ` [PATCH v2 0/8] Implement call_rcu_lazy() and miscellaneous fixes Paul E. McKenney
2022-07-08 4:17 ` Joel Fernandes
2022-07-08 22:45 ` Paul E. McKenney
2022-07-10 1:38 ` Joel Fernandes
2022-07-10 15:47 ` Paul E. McKenney
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