Re: mm: LTP/memcg testcase regression induced by 8cd7c588decf..66ce520bb7c2 series

From: Mel Gorman
Date: Tue Nov 23 2021 - 04:13:11 EST


On Sun, Nov 21, 2021 at 11:57:20AM +0100, Mike Galbraith wrote:
> Greetings,
>
> FYI, something in this series causes LTP controllers::memcg_regression
> testcase to hang forever. Verified via brute force revert of the lot.
>
> After letting box moan for 4.5 hours, I poked ^C repeatedly, but runltp
> didn't exit/recover gracefully, and ps hung, so I nuked the box. All
> memcg_test_1 instances were stuck in reclaim_throttle().
>

I'll see can I reproduce this but do you know offhand what the test is
doing and what the expected outcome is? A possibility is that this is a
test that is driving the machine near OOM (or at least memcg OOM) and
getting throttled instead of getting killed.

--
Mel Gorman
SUSE Labs