From: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
To: Michal Hocko <mhocko@kernel.org>
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 19:09:22 +0300 [thread overview]
Message-ID: <177f56cd-6e10-4d2e-7a3e-23276222ba19@yandex-team.ru> (raw)
In-Reply-To: <20190522155220.GB4374@dhcp22.suse.cz>
On 22.05.2019 18:52, Michal Hocko wrote:
> 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?
>
It may be trivial right now but not fixed.
Adding new kinds of memory may change this definition.
For example hypothetical 'GPU buffers' may be handled as 'userspace' memory.
next prev parent reply other threads:[~2019-05-22 16:09 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
2019-05-22 16:09 ` Konstantin Khlebnikov [this message]
2019-05-22 17:03 ` Roman Gushchin
2019-05-22 18:18 ` Konstantin Khlebnikov
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