Re: INFO: rcu_sched detected stalls on CPUs/tasks with `kswapd` and `mem_cgroup_shrink_node`
From: Boris Zhmurov
Date: Fri Dec 02 2016 - 11:41:21 EST
Paul E. McKenney Thu Dec 01 2016 - 14:39:21 EST:
>> Well, I can confirm, that replacing cond_resched_rcu_qs in
>> shrink_node_memcg by cond_resched also makes dmesg clean from RCU
>> CPU stall warnings.
>>
>> I've attached patch (just modification of Paul's patch), that
>> fixes RCU stall messages in situations, when all memory is used by
>> couchbase/memcached + fs cache and linux starts to use swap.
> Nice! Just to double-check, could you please also test your patch
> above with these two commits from -rcu?
>
> d2db185bfee8 ("rcu: Remove short-term CPU kicking") f8f127e738e3
> ("rcu: Add long-term CPU kicking")
>
> Thanx, Paul
Looks like patches d2db185bfee8 and f8f127e738e3 change nothing.
With cond_resched() in shrink_node_memcg and these two patches dmesg is
clean. No any RCU CPU stall messages.
Thanks.
--
Boris Zhmurov
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