lkml.org 
[lkml]   [2020]   [Oct]   [29]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH v2] mm: memcg: link page counters to root if use_hierarchy is false
Hi.

On Mon, Oct 26, 2020 at 04:13:26PM -0700, Roman Gushchin <guro@fb.com> wrote:
> Please note, that in the non-hierarchical mode all objcgs are always
> reparented to the root memory cgroup, even if the hierarchy has more
> than 1 level. This patch doesn't change it.
>
> The patch also doesn't affect how the hierarchical mode is working,
> which is the only sane and truly supported mode now.
I agree with the patch and you can add
Reviewed-by: Michal Koutný <mkoutny@suse.com>

However, it effectively switches any users of root.use_hierarchy=0 (if there
are any, watching the counters of root memcg) into root.use_hierarchy=1.
So I'd show them the warning even with a single level of cgroups, i.e.
add this hunk

@@ -5356,12 +5356,11 @@
page_counter_init(&memcg->kmem, &root_mem_cgroup->kmem);
page_counter_init(&memcg->tcpmem, &root_mem_cgroup->tcpmem);
/*
- * Deeper hierachy with use_hierarchy == false doesn't make
+ * Hierachy with use_hierarchy == false doesn't make
* much sense so let cgroup subsystem know about this
* unfortunate state in our controller.
*/
- if (parent != root_mem_cgroup)
- memory_cgrp_subsys.broken_hierarchy = true;
+ memory_cgrp_subsys.broken_hierarchy = true;
}

/* The following stuff does not apply to the root */

What do you think?

Michal
[unhandled content-type:application/pgp-signature]
\
 
 \ /
  Last update: 2020-10-29 16:39    [W:0.925 / U:0.384 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site