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From: Michal Hocko <mhocko@kernel.org>
To: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Cc: linux-mm@kvack.org, Andrew Morton <akpm@linux-foundation.org>,
	linux-kernel@vger.kernel.org, Roman Gushchin <guro@fb.com>,
	Vlastimil Babka <vbabka@suse.cz>,
	Johannes Weiner <hannes@cmpxchg.org>
Subject: Re: [PATCH] proc/meminfo: add MemKernel counter
Date: Wed, 22 May 2019 17:52:20 +0200	[thread overview]
Message-ID: <20190522155220.GB4374@dhcp22.suse.cz> (raw)
In-Reply-To: <155853600919.381.8172097084053782598.stgit@buzz>

On Wed 22-05-19 17:40:09, Konstantin Khlebnikov wrote:
> Some kinds of kernel allocations are not accounted or not show in meminfo.
> For example vmalloc allocations are tracked but overall size is not shown
> for performance reasons. There is no information about network buffers.
> 
> In most cases detailed statistics is not required. At first place we need
> information about overall kernel memory usage regardless of its structure.
> 
> This patch estimates kernel memory usage by subtracting known sizes of
> free, anonymous, hugetlb and caches from total memory size: MemKernel =
> MemTotal - MemFree - Buffers - Cached - SwapCached - AnonPages - Hugetlb.

Why do we need to export something that can be calculated in the
userspace trivially? Also is this really something the number really
meaningful? Say you have a driver that exports memory to the userspace
via mmap but that memory is not accounted. Is this really a kernel
memory?

-- 
Michal Hocko
SUSE Labs

  parent reply	other threads:[~2019-05-22 15:52 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-05-22 14:40 [PATCH] proc/meminfo: add MemKernel counter Konstantin Khlebnikov
2019-05-22 15:01 ` Vlastimil Babka
2019-05-22 15:30   ` Konstantin Khlebnikov
2019-05-22 15:52 ` Michal Hocko [this message]
2019-05-22 16:09   ` Konstantin Khlebnikov
2019-05-22 17:03     ` Roman Gushchin
2019-05-22 18:18       ` Konstantin Khlebnikov

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