From: Michal =?unknown-8bit?q?Koutn=C3=BD?= <mkoutny@suse.com>
To: ltp@lists.linux.it
Subject: [LTP] [PATCH v2] mm: memcg: link page counters to root if use_hierarchy is false
Date: Thu, 29 Oct 2020 16:39:21 +0100 [thread overview]
Message-ID: <20201029153921.GC9928@blackbook> (raw)
In-Reply-To: <20201026231326.3212225-1-guro@fb.com>
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 Koutn? <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
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From: "Michal Koutný" <mkoutny@suse.com>
To: Roman Gushchin <guro@fb.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Shakeel Butt <shakeelb@google.com>,
Johannes Weiner <hannes@cmpxchg.org>,
Michal Hocko <mhocko@kernel.org>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
kernel-team@fb.com, ltp@lists.linux.it,
Richard Palethorpe <rpalethorpe@suse.com>,
stable@vger.kernel.org
Subject: Re: [PATCH v2] mm: memcg: link page counters to root if use_hierarchy is false
Date: Thu, 29 Oct 2020 16:39:21 +0100 [thread overview]
Message-ID: <20201029153921.GC9928@blackbook> (raw)
In-Reply-To: <20201026231326.3212225-1-guro@fb.com>
[-- Attachment #1: Type: text/plain, Size: 1355 bytes --]
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
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next prev parent reply other threads:[~2020-10-29 15:39 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-26 23:13 [LTP] [PATCH v2] mm: memcg: link page counters to root if use_hierarchy is false Roman Gushchin
2020-10-26 23:13 ` Roman Gushchin
2020-10-29 15:39 ` Michal =?unknown-8bit?q?Koutn=C3=BD?= [this message]
2020-10-29 15:39 ` Michal Koutný
2020-10-29 17:05 ` [LTP] " Roman Gushchin
2020-10-29 17:05 ` Roman Gushchin
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