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Re: [PATCH] do not count pages in holes with sparsemem

Subject: Re: [PATCH] do not count pages in holes with sparsemem
From: Atsushi Nemoto <>
Date: Thu, 27 Jul 2006 00:21:53 +0900 (JST)
In-reply-to: <>
Original-recipient: rfc822;
References: <> <> <>
On Wed, 26 Jul 2006 16:33:45 +0200, Franck Bui-Huu <> 
> I don't think that's correct to mark them as "reserved". Basicaly
> "reserved" means that it belongs to the kernel (code or data), these
> holes are not and we will end up to have wrong value as you pointed
> out.
> Having quick look at sparsemem code, I don't think that it expects
> to have holes inside a section, do it ? If so you probably have to
> fix up your section size...

Yes, for such small holes, sparsemem and flatmem is same.  We can use
smaller section size to save more memory, but I suppose it will be a
bit slower.

> > Talking about nr_kernel_pages (calculated by zones_size[] and
> > zones_holes[]) and num_physpages, these values are used to determine
> > sizes of some kernel data structures, it would be better to set more
> > precise value for them.
> > 
> > While large holes in a section wastes some memory, make the section
> > size customizable might be a good idea.  Anyone?  ;-)
> > 
> hey, you are working in this area, aren't you ? ;)

Well, not actively now since I'm comfort with 256MB section size :-)

Atsushi Nemoto

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