Re: [PATCH 4/4] selftests: memcg: Remove protection from top level memcg

David Vernet
2022-05-13T19:14:59Z

On Fri, May 13, 2022 at 07:18:11PM +0200, Michal Koutný wrote:
> The reclaim is triggered by memory limit in a subtree, therefore the
> testcase does not need configured protection against external reclaim.
>
> Also, correct/deduplicate respective comments
>
> Signed-off-by: Michal Koutný <mkoutny-IBi9RG/b67k@public.gmane.org>
> ---
> tools/testing/selftests/cgroup/test_memcontrol.c | 12 ++++--------
> 1 file changed, 4 insertions(+), 8 deletions(-)
>
> diff --git a/tools/testing/selftests/cgroup/test_memcontrol.c b/tools/testing/selftests/cgroup/test_memcontrol.c
> index 9ffacf024bbd..9d370aafd799 100644
> --- a/tools/testing/selftests/cgroup/test_memcontrol.c
> +++ b/tools/testing/selftests/cgroup/test_memcontrol.c
> @@ -247,7 +247,7 @@ static int cg_test_proc_killed(const char *cgroup)
>
> /*
> * First, this test creates the following hierarchy:
> - * A memory.min = 50M, memory.max = 200M
> + * A memory.min = 0, memory.max = 200M
> * A/B memory.min = 50M, memory.current = 50M
> * A/B/C memory.min = 75M, memory.current = 50M
> * A/B/D memory.min = 25M, memory.current = 50M
> @@ -257,7 +257,7 @@ static int cg_test_proc_killed(const char *cgroup)
> * Usages are pagecache, but the test keeps a running
> * process in every leaf cgroup.
> * Then it creates A/G and creates a significant
> - * memory pressure in it.
> + * memory pressure in A.
> *
> * A/B memory.current ~= 50M
> * A/B/C memory.current ~= 29M
> @@ -335,8 +335,6 @@ static int test_memcg_min(const char *root)
> (void *)(long)fd);
> }
>
> - if (cg_write(parent[0], "memory.min", "50M"))
> - goto cleanup;
> if (cg_write(parent[1], "memory.min", "50M"))
> goto cleanup;
> if (cg_write(children[0], "memory.min", "75M"))
> @@ -404,8 +402,8 @@ static int test_memcg_min(const char *root)
>
> /*
> * First, this test creates the following hierarchy:
> - * A memory.low = 50M, memory.max = 200M
> - * A/B memory.low = 50M, memory.current = 50M
> + * A memory.low = 0, memory.max = 200M
> + * A/B memory.low = 50M, memory.current = ...

Is there a reason that we would adjust this comment but not the A/B comment
from above in from test_memcg_low()? In both cases, I would just remove the
memory.current = ... part altogether, as Roman suggested.

> * A/B/C memory.low = 75M, memory.current = 50M
> * A/B/D memory.low = 25M, memory.current = 50M
> * A/B/E memory.low = 0, memory.current = 50M
> @@ -490,8 +488,6 @@ static int test_memcg_low(const char *root)
> goto cleanup;
> }
>
> - if (cg_write(parent[0], "memory.low", "50M"))
> - goto cleanup;
> if (cg_write(parent[1], "memory.low", "50M"))
> goto cleanup;
> if (cg_write(children[0], "memory.low", "75M"))
> --
> 2.35.3
>

Looks good otherwise.

Reviewed-by: David Vernet <void-gq6j2QGBifHby3iVrkZq2A@public.gmane.org>