Re: [PATCH 2/4] kselftests: memcg: speed up the memory.high test

[David Vernet <void@manifault.com>]

On Thu, Apr 14, 2022 at 05:01:31PM -0700, Roman Gushchin wrote:
> After commit 0e4b01df8659 ("mm, memcg: throttle allocators when
> failing reclaim over memory.high") allocating memory over memory.high
> became very time consuming. But it's exactly what the memory.high
> test from cgroup kselftests is doing: it tries to allocate 100M with
> 30M memory.high value. It takes forever to complete.
> 
> In order to keep it passing (or failing) in a reasonable amount of
> time let's try to allocate only a little over 30M: 31M to be precise.
> 
> With this change test_memcontrol finishes in a reasonable amount of
> time:
>   $ time ./test_memcontrol
>   ok 1 test_memcg_subtree_control
>   ok 2 test_memcg_current
>   ok 3 test_memcg_min
>   ok 4 test_memcg_low
>   ok 5 test_memcg_high
>   ok 6 test_memcg_max
>   ok 7 test_memcg_oom_events
>   ok 8 test_memcg_swap_max
>   ok 9 test_memcg_sock
>   ok 10 test_memcg_oom_group_leaf_events
>   ok 11 test_memcg_oom_group_parent_events
>   ok 12 test_memcg_oom_group_score_events
> 
>   real	0m2.273s
>   user	0m0.064s
>   sys	0m0.739s
> 
> Signed-off-by: Roman Gushchin <roman.gushchin@linux.dev>
> Cc: Chris Down <chris@chrisdown.name>
> Cc: Johannes Weiner <hannes@cmpxchg.org>
> ---
>  tools/testing/selftests/cgroup/test_memcontrol.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/tools/testing/selftests/cgroup/test_memcontrol.c b/tools/testing/selftests/cgroup/test_memcontrol.c
> index 00b430e7f2a2..9c1f19fe2e37 100644
> --- a/tools/testing/selftests/cgroup/test_memcontrol.c
> +++ b/tools/testing/selftests/cgroup/test_memcontrol.c
> @@ -607,7 +607,7 @@ static int test_memcg_high(const char *root)
>  	if (cg_write(memcg, "memory.high", "30M"))
>  		goto cleanup;
>  
> -	if (cg_run(memcg, alloc_anon, (void *)MB(100)))
> +	if (cg_run(memcg, alloc_anon, (void *)MB(31)))
>  		goto cleanup;
>  
>  	if (!cg_run(memcg, alloc_pagecache_50M_check, NULL))
> -- 
> 2.35.1
> 

Thanks for re-sending this. Looks good.

Reviewed-by: David Vernet <void@manifault.com>