LKML Archive on lore.kernel.org
help / color / mirror / Atom feed
From: KyongHo Cho <pullip.linux@gmail.com>
To: Minchan Kim <minchan.kim@gmail.com>
Cc: linux-arm-kernel@lists.infradead.org, linux-mm@kvack.org,
	linux-kernel@vger.kernel.org, linux-samsung-soc@vger.kernel.org,
	Kukjin Kim <kgene.kim@samsung.com>,
	Ilho Lee <ilho215.lee@samsung.com>,
	KeyYoung Park <keyyoung.park@samsung.com>,
	KyongHo Cho <pullip.cho@samsung.com>
Subject: Re: [PATCH] ARM: mm: Regarding section when dealing with meminfo
Date: Fri, 21 Jan 2011 02:52:34 +0900	[thread overview]
Message-ID: <AANLkTimf4oqEs4Oq1gMEjRsqhGM=vYkU6zm2MSuRBVdk@mail.gmail.com> (raw)
In-Reply-To: <AANLkTi=MizfGY4koMmRHprts6Ji3ofeSZPBBTiH1FDcn@mail.gmail.com>

On Fri, Jan 21, 2011 at 2:44 AM, Minchan Kim <minchan.kim@gmail.com> wrote:
> Fix linux-arm-kernel address.
>
Thank you!
Too late in the night:)

> On Fri, Jan 21, 2011 at 2:43 AM, Minchan Kim <minchan.kim@gmail.com> wrote:
>> Restore Cced.
>>
>> On Fri, Jan 21, 2011 at 2:24 AM, KyongHo Cho <pullip.linux@gmail.com> wrote:
>>> On Thu, Jan 20, 2011 at 11:28 PM, Minchan Kim <minchan.kim@gmail.com> wrote:
>>>> On Thu, Jan 20, 2011 at 06:45:39PM +0900, KyongHo Cho wrote:
>>>>> Sparsemem allows that a bank of memory spans over several adjacent
>>>>> sections if the start address and the end address of the bank
>>>>> belong to different sections.
>>>>> When gathering statictics of physical memory in mem_init() and
>>>>> show_mem(), this possiblity was not considered.
>>>>
>>>> Please write down the result if we doesn't consider this patch.
>>>> I can understand what happens but for making good description and review,
>>>> merging easily, it would be better to write down the result without
>>>> the patch explicitly.
>>>>
>>> As we know that each section has its own memmap and
>>> a contiguous chunk of physical memory that is represented by 'bank' in meminfo
>>> can be larger than the size of a section.
>>> "page++" in the current implementation can access invalid memory area.
>>> The size of the section is 256 MiB in ARM and the number of banks in
>>> meminfo is 8.
>>> This means that the maximum size of the physical memory cannot be grow than 2GiB
>>> to avoid this problem in the current implementation.
>>> Thus we need to fix the calculation of the last page descriptor in
>>> terms of sections.
>>>
>>> This patch determines the last page descriptor in a memmap with
>>> min(last_pfn_of_bank, last_pfn_of_current_section)
>>> If there remains physical memory not consumed, it calculates the last
>>> page descriptor
>>> with min(last_pfn_of_bank, last_pfn_of_next_section).
>>>
>>>>
>>>> Hmm.. new ifndef magic makes code readability bad.
>>>> Couldn't we do it by simple pfn iterator not page and pfn_valid check?
>>>>
>>> True.
>>> We need to consider the implementation again.
>>> I think the previous implementation gave the importance to the
>>> efficiency but to the readability.
>>>
>>
>> Please consider readability and consistency with other architectures
>> if we can do. :)
>> Thanks.
>>
>> --
>> Kind regards,
>> Minchan Kim
>>
>
>
>
> --
> Kind regards,
> Minchan Kim
>

  reply	other threads:[~2011-01-20 17:52 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-01-20  9:45 KyongHo Cho
2011-01-20 14:28 ` Minchan Kim
2011-01-20 17:25   ` Dave Hansen
     [not found]   ` <AANLkTinXAiShaf1f69ufVHg7KPaY5j=jmOTtK71GNNp5@mail.gmail.com>
2011-01-20 17:43     ` Minchan Kim
2011-01-20 17:44       ` Minchan Kim
2011-01-20 17:52         ` KyongHo Cho [this message]
2011-01-20 17:20 ` Dave Hansen
     [not found]   ` <AANLkTi=nsAOtLPK75Wy5Rm8pfWob8xTP5259DyYuxR9J@mail.gmail.com>
2011-01-20 17:48     ` KyongHo Cho
2011-01-20 18:04     ` Dave Hansen
2011-01-20 18:01   ` Russell King - ARM Linux
2011-01-20 18:11     ` Dave Hansen
2011-01-23 18:05       ` Russell King - ARM Linux
2011-01-24 16:52         ` Dave Hansen
2011-01-24 17:58           ` Russell King - ARM Linux
2011-01-24 18:47             ` Dave Hansen
2011-01-25  0:33             ` KyongHo Cho
2011-01-21  2:12     ` KyongHo Cho
2011-01-21 10:38       ` Russell King - ARM Linux
2011-01-21 11:15         ` KyongHo Cho

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to='AANLkTimf4oqEs4Oq1gMEjRsqhGM=vYkU6zm2MSuRBVdk@mail.gmail.com' \
    --to=pullip.linux@gmail.com \
    --cc=ilho215.lee@samsung.com \
    --cc=keyyoung.park@samsung.com \
    --cc=kgene.kim@samsung.com \
    --cc=linux-arm-kernel@lists.infradead.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-mm@kvack.org \
    --cc=linux-samsung-soc@vger.kernel.org \
    --cc=minchan.kim@gmail.com \
    --cc=pullip.cho@samsung.com \
    --subject='Re: [PATCH] ARM: mm: Regarding section when dealing with meminfo' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).