linux-kernel - Re: (2) [RESEND PATCH 00/10] memblock: introduce memsize showing reserved memory

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Date: Thu, 23 May 2024 17:34:50 +0300
From: Mike Rapoport <rppt@...nel.org>
To: Jaewon Kim <jaewon31.kim@...sung.com>
Cc: "vbabka@...e.cz" <vbabka@...e.cz>,
	"akpm@...ux-foundation.org" <akpm@...ux-foundation.org>,
	"linux-mm@...ck.org" <linux-mm@...ck.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"jaewon31.kim@...il.com" <jaewon31.kim@...il.com>,
	"tkjos@...gle.com" <tkjos@...gle.com>
Subject: Re: (2) [RESEND PATCH 00/10] memblock: introduce memsize showing
 reserved memory

On Tue, May 21, 2024 at 07:17:53PM +0900, Jaewon Kim wrote:
> >On Tue, May 21, 2024 at 11:53:29AM +0900, Jaewon Kim wrote:
> >> >--------- Original Message ---------
> >> >Sender : 김재원 <jaewon31.kim@...sung.com>System Performance Lab.(MX)/삼성전자
> >> >Date   : 2024-05-21 11:40 (GMT+9)
> >> >Title  : [RESEND PATCH 00/10] memblock: introduce memsize showing reserved memory
> >> >?
> >> >Some of memory regions can be reserved for a specific purpose. They are
> >> >usually defined through reserved-memory in device tree. If only size
> >> >without address is specified in device tree, the address of the region
> >> >will be determined at boot time.
> >> >
> >> >We may find the address of the memory regions through booting log, but
> >> >it does not show all. And it could be hard to catch the very beginning
> >> >log. The memblock_dump_all shows all memblock status but it does not
> >> >show region name and its information is difficult to summarize.
> >> >
> >> >This patch introduce a debugfs node, memblock/memsize, to see reserved
> >> >memory easily.
> >> 
> >> This is actually RESEND as it was introduced 2 years ago.
> >> Please refer to https://lore.kernel.org/linux-mm/YkQB6Ah603yPR3qf@kernel.org/#t
> >> 
> >> > But you never provided details about *why* you want this information exposed.
> >> 
> >> For your question, I'd like to say ;
> >> We can see the same format and exact information between different version of kernel status.
> >> 
> >> 1) Internally we can check if the reserved memory changes.
> >> 2) Externally we can communicate between chipset vendors and OEM, with a same format.
> >
> >Why the existing debugfs interface is not sufficient?
> 
> debugfs/memblock/memory & debugfs/memblock/reserved have changed its
> format but still does not show name, reusable, kernel size.  If memory is
> reserved from memblock, and did not freed back to memblock. Memblock does
> not know even after the memory is freed to system.  I think a simple
> debug interface is needed to easily communicate with others or compare
> different SW releases.

I still don't understand what problem are you trying to solve with these
patches. 
 
-- 
Sincerely yours,
Mike.