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Date:   Mon, 31 Jan 2022 12:51:48 -0800
From:   Roman Gushchin <guro@fb.com>
To:     Waiman Long <longman@redhat.com>
CC:     Johannes Weiner <hannes@cmpxchg.org>,
        Michal Hocko <mhocko@kernel.org>,
        Vladimir Davydov <vdavydov.dev@gmail.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Petr Mladek <pmladek@suse.com>,
        Steven Rostedt <rostedt@goodmis.org>,
        Sergey Senozhatsky <senozhatsky@chromium.org>,
        Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
        Rasmus Villemoes <linux@rasmusvillemoes.dk>,
        <linux-kernel@vger.kernel.org>, <cgroups@vger.kernel.org>,
        <linux-mm@kvack.org>, Ira Weiny <ira.weiny@intel.com>,
        Mike Rapoport <rppt@kernel.org>,
        David Rientjes <rientjes@google.com>,
        Rafael Aquini <aquini@redhat.com>
Subject: Re: [PATCH v3 3/4] mm/page_owner: Print memcg information
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References: <20220131192308.608837-1-longman@redhat.com>
 <20220131192308.608837-4-longman@redhat.com>
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On Mon, Jan 31, 2022 at 02:23:07PM -0500, Waiman Long wrote:
> It was found that a number of offlined memcgs were not freed because
> they were pinned by some charged pages that were present. Even "echo
> 1 > /proc/sys/vm/drop_caches" wasn't able to free those pages. These
> offlined but not freed memcgs tend to increase in number over time with
> the side effect that percpu memory consumption as shown in /proc/meminfo
> also increases over time.
> 
> In order to find out more information about those pages that pin
> offlined memcgs, the page_owner feature is extended to print memory
> cgroup information especially whether the cgroup is offlined or not.
> 
> Signed-off-by: Waiman Long <longman@redhat.com>
> Acked-by: David Rientjes <rientjes@google.com>

Acked-by: Roman Gushchin <guro@fb.com>

Thanks!