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Date: Wed, 19 Aug 2009 08:57:03 +0900
From: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
To: Amerigo Wang <amwang@redhat.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>, linux-kernel@vger.kernel.org,
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       Fenghua Yu <fenghua.yu@intel.com>, Ingo Molnar <mingo@elte.hu>,
       Anton Vorontsov <avorontsov@ru.mvista.com>
Subject: Re: [Patch 8/8] kexec: allow to shrink reserved memory
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On Tue, 18 Aug 2009 18:35:32 +0800
Amerigo Wang <amwang@redhat.com> wrote:

> KAMEZAWA Hiroyuki wrote:
> > On Tue, 18 Aug 2009 14:31:23 +0800
> > Amerigo Wang <amwang@redhat.com> wrote:
> >   
> >>>     It's hidden from the system before mem_init() ?
> >>>   
> >>>       
> >> Not sure, but probably yes. It is reserved in setup_arch() which is 
> >> before mm_init() which calls mem_init().
> >>
> >> Do you have any advice to free that reserved memory after boot? :)
> >>
> >>     
> >
> > Let's see arch/x86/mm/init.c::free_initmem()
> >
> > Maybe it's all you want.
> >
> > 	- ClearPageReserved()
> > 	- init_page_count()
> > 	- free_page()
> > 	- totalram_pages++
> >   
> 
> Just FYI: calling ClearPageReserved() caused an oops: "Unable to handle 
> paging request".
> 
> I am trying to figure out why...
> 
Hmm...then....memmap is not there.
pfn_valid() check will help you. What arch ? x86-64 ?

Thanks,
-Kame