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Groups > linux.kernel > #1536764
| From | Donald Buczek <buczek@molgen.mpg.de> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | Re: INFO: rcu_sched detected stalls on CPUs/tasks with `kswapd` and `mem_cgroup_shrink_node` |
| Date | 2016-12-06 09:40 +0100 |
| Message-ID | <sLjs5-87p-1@gated-at.bofh.it> (permalink) |
| References | (8 earlier) <sIteh-22H-15@gated-at.bofh.it> <sJajf-4SL-21@gated-at.bofh.it> <sJb5D-5oB-7@gated-at.bofh.it> <sJbyF-5yf-9@gated-at.bofh.it> <sJSaB-1Wx-19@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
On 12/02/16 10:14, Donald Buczek wrote:
> On 11/30/16 12:43, Donald Buczek wrote:
>> On 11/30/16 12:09, Michal Hocko wrote:
>>> [CCing Paul]
>>>
>>> On Wed 30-11-16 11:28:34, Donald Buczek wrote:
>>> [...]
>>>> shrink_active_list gets and releases the spinlock and calls
>>>> cond_resched().
>>>> This should give other tasks a chance to run. Just as an
>>>> experiment, I'm
>>>> trying
>>>>
>>>> --- a/mm/vmscan.c
>>>> +++ b/mm/vmscan.c
>>>> @@ -1921,7 +1921,7 @@ static void shrink_active_list(unsigned long
>>>> nr_to_scan,
>>>> spin_unlock_irq(&pgdat->lru_lock);
>>>>
>>>> while (!list_empty(&l_hold)) {
>>>> - cond_resched();
>>>> + cond_resched_rcu_qs();
>>>> page = lru_to_page(&l_hold);
>>>> list_del(&page->lru);
>>>>
>>>> and didn't hit a rcu_sched warning for >21 hours uptime now. We'll
>>>> see.
>>> This is really interesting! Is it possible that the RCU stall detector
>>> is somehow confused?
>>
>> Wait... 21 hours is not yet a test result.
>
> For the records: We didn't have any stall warnings after 2 days and 20
> hours now and so I'm quite confident, that my above patch fixed the
> problem for v4.8.0. On previous boots the rcu warnings started after
> 37,0.2,1,2,0.8 hours uptime.
>
> Now I've applied this patch to stable latest (v4.8.11) on another
> backup machine which suffered even more rcu stalls.
>
> Donald
>
>> [...]
For the records: After 3 days and 21 hours we've got a rcu stall warning
again [1]. So my patch didn't fix it.
Trying "[PATCH] mm, vmscan: add cond_resched into shrink_node_memcg"
from Michal Hocko [2] on top of v4.8.12 on both servers now.
[1] https://owww.molgen.mpg.de/~buczek/321322/2016-12-06.dmesg.txt
[2] https://marc.info/?i=20161202095841.16648-1-mhocko%40kernel.org
--
Donald Buczek
buczek@molgen.mpg.de
Tel: +49 30 8413 1433
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Re: INFO: rcu_sched detected stalls on CPUs/tasks with `kswapd` and `mem_cgroup_shrink_node` Donald Buczek <buczek@molgen.mpg.de> - 2016-11-27 10:20 +0100
Re: INFO: rcu_sched detected stalls on CPUs/tasks with `kswapd` and `mem_cgroup_shrink_node` Michal Hocko <mhocko@kernel.org> - 2016-11-28 12:10 +0100
Re: INFO: rcu_sched detected stalls on CPUs/tasks with `kswapd` and `mem_cgroup_shrink_node` Paul Menzel <pmenzel@molgen.mpg.de> - 2016-11-28 13:30 +0100
Re: INFO: rcu_sched detected stalls on CPUs/tasks with `kswapd` and `mem_cgroup_shrink_node` Donald Buczek <buczek@molgen.mpg.de> - 2016-11-30 11:30 +0100
Re: INFO: rcu_sched detected stalls on CPUs/tasks with `kswapd` and `mem_cgroup_shrink_node` Michal Hocko <mhocko@kernel.org> - 2016-11-30 12:20 +0100
Re: INFO: rcu_sched detected stalls on CPUs/tasks with `kswapd` and `mem_cgroup_shrink_node` Donald Buczek <buczek@molgen.mpg.de> - 2016-11-30 12:50 +0100
Re: INFO: rcu_sched detected stalls on CPUs/tasks with `kswapd` and `mem_cgroup_shrink_node` Donald Buczek <buczek@molgen.mpg.de> - 2016-12-02 10:20 +0100
Re: INFO: rcu_sched detected stalls on CPUs/tasks with `kswapd` and `mem_cgroup_shrink_node` Donald Buczek <buczek@molgen.mpg.de> - 2016-12-06 09:40 +0100
Re: INFO: rcu_sched detected stalls on CPUs/tasks with `kswapd` and `mem_cgroup_shrink_node` "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2016-11-30 13:00 +0100
Re: INFO: rcu_sched detected stalls on CPUs/tasks with `kswapd` and `mem_cgroup_shrink_node` Paul Menzel <pmenzel@molgen.mpg.de> - 2016-11-30 13:40 +0100
Re: INFO: rcu_sched detected stalls on CPUs/tasks with `kswapd` and `mem_cgroup_shrink_node` "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2016-11-30 15:40 +0100
Re: INFO: rcu_sched detected stalls on CPUs/tasks with `kswapd` and `mem_cgroup_shrink_node` "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2016-11-30 13:00 +0100
Re: INFO: rcu_sched detected stalls on CPUs/tasks with `kswapd` and `mem_cgroup_shrink_node` Michal Hocko <mhocko@kernel.org> - 2016-11-30 14:20 +0100
Re: INFO: rcu_sched detected stalls on CPUs/tasks with `kswapd` and `mem_cgroup_shrink_node` "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2016-11-30 15:40 +0100
Re: INFO: rcu_sched detected stalls on CPUs/tasks with `kswapd` and `mem_cgroup_shrink_node` Peter Zijlstra <peterz@infradead.org> - 2016-11-30 17:40 +0100
Re: INFO: rcu_sched detected stalls on CPUs/tasks with `kswapd` and `mem_cgroup_shrink_node` Michal Hocko <mhocko@kernel.org> - 2016-11-30 18:10 +0100
Re: INFO: rcu_sched detected stalls on CPUs/tasks with `kswapd` and `mem_cgroup_shrink_node` "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2016-11-30 18:30 +0100
Re: INFO: rcu_sched detected stalls on CPUs/tasks with `kswapd` and `mem_cgroup_shrink_node` Michal Hocko <mhocko@kernel.org> - 2016-11-30 18:40 +0100
Re: INFO: rcu_sched detected stalls on CPUs/tasks with `kswapd` and `mem_cgroup_shrink_node` Peter Zijlstra <peterz@infradead.org> - 2016-11-30 19:00 +0100
Re: INFO: rcu_sched detected stalls on CPUs/tasks with `kswapd` and `mem_cgroup_shrink_node` "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2016-11-30 22:40 +0100
Re: INFO: rcu_sched detected stalls on CPUs/tasks with `kswapd` and `mem_cgroup_shrink_node` Peter Zijlstra <peterz@infradead.org> - 2016-12-01 06:40 +0100
Re: INFO: rcu_sched detected stalls on CPUs/tasks with `kswapd` and `mem_cgroup_shrink_node` "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2016-12-01 13:50 +0100
Re: INFO: rcu_sched detected stalls on CPUs/tasks with `kswapd` and `mem_cgroup_shrink_node` Peter Zijlstra <peterz@infradead.org> - 2016-12-01 17:40 +0100
Re: INFO: rcu_sched detected stalls on CPUs/tasks with `kswapd` and `mem_cgroup_shrink_node` "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2016-12-01 18:00 +0100
Re: INFO: rcu_sched detected stalls on CPUs/tasks with `kswapd` and `mem_cgroup_shrink_node` Peter Zijlstra <peterz@infradead.org> - 2016-12-01 19:20 +0100
Re: INFO: rcu_sched detected stalls on CPUs/tasks with `kswapd` and `mem_cgroup_shrink_node` "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2016-12-01 19:50 +0100
Re: INFO: rcu_sched detected stalls on CPUs/tasks with `kswapd` and `mem_cgroup_shrink_node` Peter Zijlstra <peterz@infradead.org> - 2016-12-01 20:00 +0100
Re: INFO: rcu_sched detected stalls on CPUs/tasks with `kswapd` and `mem_cgroup_shrink_node` "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2016-11-30 18:10 +0100
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