From: <Peter.Enderborg@sony.com>
To: <mhocko@suse.com>
Cc: <christian.koenig@amd.com>, <linux-kernel@vger.kernel.org>,
<linux-fsdevel@vger.kernel.org>, <sumit.semwal@linaro.org>,
<adobriyan@gmail.com>, <akpm@linux-foundation.org>,
<songmuchun@bytedance.com>, <guro@fb.com>, <shakeelb@google.com>,
<neilb@suse.de>, <samitolvanen@google.com>, <rppt@kernel.org>,
<linux-media@vger.kernel.org>, <dri-devel@lists.freedesktop.org>,
<linaro-mm-sig@lists.linaro.org>, <willy@infradead.org>
Subject: Re: [PATCH v4] dma-buf: Add DmaBufTotal counter in meminfo
Date: Tue, 20 Apr 2021 09:25:51 +0000 [thread overview]
Message-ID: <532d6d7e-372c-1524-d015-e15d79fcf11c@sony.com> (raw)
In-Reply-To: <YH6bASnaRIV4DGpI@dhcp22.suse.cz>
On 4/20/21 11:12 AM, Michal Hocko wrote:
> On Tue 20-04-21 09:02:57, Peter.Enderborg@sony.com wrote:
>>>> But that isn't really system memory at all, it's just allocated device
>>>> memory.
>>> OK, that was not really clear to me. So this is not really accounted to
>>> MemTotal? If that is really the case then reporting it into the oom
>>> report is completely pointless and I am not even sure /proc/meminfo is
>>> the right interface either. It would just add more confusion I am
>>> afraid.
>>>
>> Why is it confusing? Documentation is quite clear:
> Because a single counter without a wider context cannot be put into any
> reasonable context. There is no notion of the total amount of device
> memory usable for dma-buf. As Christian explained some of it can be RAM
> based. So a single number is rather pointless on its own in many cases.
>
> Or let me just ask. What can you tell from dma-bud: $FOO kB in its
> current form?
It is better to be blind? The value can still be used a relative metric.
You collect the data and see how it change. And when you see
a unexpected change you start to dig in. It fore sure wont tell what line
in your application that has a bug. But it might be an indicator that
a new game trigger a leak. And it is very well specified, it exactly the
size of mapped dma-buf. For what you use dma-buf you need to know
other parts of the system.
next prev parent reply other threads:[~2021-04-20 9:26 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-17 10:40 [PATCH v4] dma-buf: Add DmaBufTotal counter in meminfo Peter Enderborg
2021-04-17 10:59 ` Christian König
2021-04-17 11:20 ` Peter.Enderborg
2021-04-17 11:54 ` Christian König
2021-04-17 12:13 ` Peter.Enderborg
2021-04-20 8:39 ` Daniel Vetter
2021-04-17 13:07 ` [External] " Muchun Song
2021-04-17 13:43 ` Peter.Enderborg
2021-04-17 14:21 ` Muchun Song
2021-04-17 15:03 ` Christian König
2021-04-19 12:16 ` Michal Hocko
2021-04-19 12:41 ` Peter.Enderborg
2021-04-19 15:00 ` Michal Hocko
2021-04-19 15:19 ` Peter.Enderborg
2021-04-19 15:44 ` Christian König
2021-04-19 16:11 ` Michal Hocko
2021-04-19 16:37 ` Christian König
2021-04-20 7:04 ` Michal Hocko
2021-04-20 7:20 ` Mike Rapoport
2021-04-20 7:47 ` Michal Hocko
2021-04-20 7:32 ` Christian König
2021-04-20 7:46 ` Michal Hocko
2021-04-20 8:00 ` Christian König
2021-04-20 8:28 ` Michal Hocko
2021-04-20 9:02 ` Peter.Enderborg
2021-04-20 9:12 ` Michal Hocko
2021-04-20 9:25 ` Peter.Enderborg [this message]
2021-04-20 11:04 ` Michal Hocko
2021-04-20 11:24 ` Peter.Enderborg
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