Re: INFO: rcu_sched detected stalls on CPUs/tasks with `kswapd` and `mem_cgroup_shrink_node`
From: Paul E. McKenney <hidden>
Date: 2016-12-02 17:15:45
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On Fri, Dec 02, 2016 at 06:02:49PM +0100, Michal Hocko wrote:
On Fri 02-12-16 08:44:08, Paul E. McKenney wrote:quoted
On Fri, Dec 02, 2016 at 07:39:24PM +0300, Boris Zhmurov wrote:quoted
Paul E. McKenney Thu Dec 01 2016 - 14:39:21 EST:quoted
quoted
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.quoted
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, PaulLooks 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.Very good! I have these two patches queued for 4.11.FWIW I have posted the cond_resched patch to Andrew [1]. I didn't CC you Paul to save you from emails as this is more MM than anything else related ;) [1] http://lkml.kernel.org/r/20161202095841.16648-1-mhocko@kernel.org
Feel free to apply: Acked-by: Paul E. McKenney <redacted> Thanx, Paul -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>