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Re: [RFC] calc_memmap_size() isn't accurate and one suggestion to improve

From Michal Hocko <mhocko@kernel.org>
Newsgroups linux.kernel
Subject Re: [RFC] calc_memmap_size() isn't accurate and one suggestion to improve
Date 2017-04-03 11:20 +0200
Message-ID <ts6jx-4Wo-25@gated-at.bofh.it> (permalink)
References <tpNXH-8w9-1@gated-at.bofh.it>
Organization linux.* mail to news gateway

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On Tue 28-03-17 09:11:37, Wei Yang wrote:
> Hi, masters,
> 
> # What I found
> 
> I found the function calc_memmap_size() may not be that accurate to get the
> pages for memmap.
> 
> The reason is:
> 
> > memmap is allocated on a node base,
> > while the calculation is on a zone base
> 
> This applies both to SPARSEMEM and FLATMEM.
> 
> For example, on my laptop with 6G memory, all the memmap space is allocated
> from ZONE_NORMAL.

Please try to be more specific. Why is this a problem? Are you trying to
fix some bad behavior or you want to make it more optimal?

I am sorry I didn't look closer into your proposal but I am quite busy
and other people are probably in a similar situation. If you want to get
a proper feedback please try to state the problem and be explicit if it
is user observable.
-- 
Michal Hocko
SUSE Labs

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Thread

[RFC] calc_memmap_size() isn't accurate and one suggestion to improve Wei Yang <richard.weiyang@gmail.com> - 2017-03-28 03:20 +0200
  Re: [RFC] calc_memmap_size() isn't accurate and one suggestion to  improve Michal Hocko <mhocko@kernel.org> - 2017-04-03 11:20 +0200
    Re: [RFC] calc_memmap_size() isn't accurate and one suggestion to  improve Wei Yang <richard.weiyang@gmail.com> - 2017-04-09 03:50 +0200

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