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

Roman Gushchin
2022-05-18T00:52:25Z

On Tue, May 17, 2022 at 05:24:43PM -0700, Andrew Morton wrote:
> On Fri, 13 May 2022 11:59:56 -0700 Roman Gushchin <roman.gushchin-fxUVXftIFDnyG1zEObXtfA@public.gmane.org> wrote:
>
> > On Fri, May 13, 2022 at 07:18:11PM +0200, Michal Koutny 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 = ...
> >
> > Can you, please, just remove "memory.current = ...", it's not
> > because obvious what "..." means here.
> >
>
> You mean this?
>
> --- a/tools/testing/selftests/cgroup/test_memcontrol.c~selftests-memcg-remove-protection-from-top-level-memcg-fix
> +++ a/tools/testing/selftests/cgroup/test_memcontrol.c
> @@ -403,15 +403,14 @@ cleanup:
> /*
> * First, this test creates the following hierarchy:
> * A memory.low = 0, memory.max = 200M
> - * A/B memory.low = 50M, memory.current = ...
> + * A/B memory.low = 50M
> * 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
> * A/B/F memory.low = 500M, memory.current = 0
> *
> * Usages are pagecache.
> - * Then it creates A/G an creates a significant
> - * memory pressure in it.
> + * Then it creates A/G and creates significant memory pressure in it.
> *
> * Then it checks actual memory usages and expects that:
> * A/B memory.current ~= 50M
> _
>
> (includes gratuitous comment cleanup)

Yes, thank you!

>
> I assume your comment in
> https://lkml.kernel.org/r/Yn6pBPq+lAXm9NG8@carbon can be addressed in a
> later patch.
>
> I'm not sure what to amke of https://lkml.kernel.org/r/Yn6pWPodGPlz+D8G@carbon
>
> Do we feel this series needs more work before merging it up?
>

Please, go ahead with it. If anything comes up, it can be addressed later.

Thanks!