linux-kernel - Re: [PATCH v2] docs: proc.rst: meminfo: briefly describe gaps in memory accounting

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Date:   Wed, 21 Apr 2021 08:35:06 +0200
From:   Michal Hocko <mhocko@...e.com>
To:     Alexey Dobriyan <adobriyan@...il.com>
Cc:     Matthew Wilcox <willy@...radead.org>,
        Mike Rapoport <rppt@...nel.org>,
        Jonathan Corbet <corbet@....net>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Eric Dumazet <eric.dumazet@...il.com>,
        Mike Rapoport <rppt@...ux.ibm.com>, linux-doc@...r.kernel.org,
        linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-mm@...ck.org, netdev@...r.kernel.org
Subject: Re: [PATCH v2] docs: proc.rst: meminfo: briefly describe gaps in
 memory accounting

On Tue 20-04-21 20:58:56, Alexey Dobriyan wrote:
> On Tue, Apr 20, 2021 at 03:57:07PM +0200, Michal Hocko wrote:
> > On Tue 20-04-21 14:24:30, Matthew Wilcox wrote:
> > > On Tue, Apr 20, 2021 at 03:13:54PM +0300, Mike Rapoport wrote:
> > > > Add a paragraph that explains that it may happen that the counters in
> > > > /proc/meminfo do not add up to the overall memory usage.
> > > 
> > > ... that is, the sum may be lower because memory is allocated for other
> > > purposes that is not reported here, right?
> > 
> > yes. Many direct page allocator users are not accounted in any of the
> > existing counters.
> 
> Does virtio_balloon dereserve special mention?

Yes

> From inside VM memory borrowing looks like one giant memory leak resulting
> in support tickets (not that people who file them read internal kernel
> documentation...)

Even if people do not read that documentation it is really good to have
a reference you can send when you are dealing with bug reports.

Thanks!

-- 
Michal Hocko
SUSE Labs