RE: [PATCH 0/8] memblock: introduce memsize showing reserved memory

Jaewon Kim
2022-03-30T07:23:16Z

>Hi,
>
>On Tue, Mar 29, 2022 at 11:46:20AM +0900, Jaewon Kim wrote:
>> >> >
>> >> >I'm still not following. The reserved region sizes are available in the
>> >> >existing memblock debugfs.
>> >> >Why the names are important? What is the value of having names for *some*
>> >> >of the reserved regions?
>> >>
>> >> Hi
>> >>
>> >> There are many memory regions in memblock debugfs memory/reserved, and some might
>> >> be splited or merged with other region. Among regions in debugfs, we can't find
>> >> the one we defined in device tree. Especially it is difficult to find the region we
>> >> described size only without start address.
>> >>
>> >> On mobile environment, memory is used by not only CPU but also GPU, Camera, Secure
>> >> world, Audio, ETC. To support them, there are many reserved regions described in
>> >> device tree. So the name is quite important to recognize a region. And with thename
>> >> we can compare reserved memory map with other map.
>> >
>> >You still didn't describe your use case. What is the problem your patches
>> >are trying to solve? Why is it important to know what is the use of particular
>> >reserved region?
>> >
>> >You propose complex mechanism that seems to fit very particular scenario
>> >and sprinkle some calls to this mechanism at random places because you need
>> >to "compare reserved memory map with other map".
>> >
>> >Does not sound convincing to me, sorry.
>>
>> As I said serveral times, I want a simple knob showing all reserved
>> memory status. The current debugfs, device tree do not show all those
>> information I want. I think you also know that. i.e. late freed pages,
>> splited or merged memblock, address defined at boot time, kernel size,
>> ETC.
>
>I know that there is not much information about reserved memory exposed and
>I understand *what* are you trying to achieve. But you never provided
>details about *why* you want this information exposed.
>
>I don't mind providing more visibility into reserved memory attributes in
>general, but I'd like to see something way more simple and localized.
>

I think the "what" is same as "why".
I want to look at all reservced memory status simply in a knob.

I also want to make in more simple and localized way, but there seems be
several ways to change reserved memory such as cmdline way, freeing after
boot, etc. I wanted to cover all those things.

That's OK. I hope someone later to try this again to show all the info.

>--
>Sincerely yours,
>Mike.