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

From: David Vernet
Date: Fri Apr 15 2022 - 10:11:44 EST


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@xxxxxxxxx>
> Cc: Chris Down <chris@xxxxxxxxxxxxxx>
> Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
> ---
> 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@xxxxxxxxxxxxx>