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From: "H. Peter Anvin" <hpa@zytor.com>
To: Jan Beulich <jbeulich@novell.com>
Cc: mingo@elte.hu, tglx@linutronix.de, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] x86-64: improve e820_search_gap()
Date: Thu, 07 May 2009 21:59:06 -0700	[thread overview]
Message-ID: <4A03BC1A.9060605@zytor.com> (raw)
In-Reply-To: <4A0199B8.76EA.0078.0@novell.com>

Jan Beulich wrote:
> Impact: bug fix
> 
> Blindly putting the gap close after max_pfn is in conflict with that
> same memory range potentially being used by hotplugged memory.
> 
> Also, make the function static to ensure there are no other users that
> could depend on the previous behavior regarding the way start_addr gets
> specified.
> 
> Signed-off-by: Jan Beulich <jbeulich@novell.com>
> 

So blindly locate it somewhere else?  How is that inherently better?
Wouldn't a machine with hotplug memory (which doesn't bother advertising
that fact so we can reserve the address space) be just as likely to use
a sparse memory space, since one can hardly expect the hardware to pack
the space (packing in hardware is why PCs generally have a
mostly-contiguous RAM space) when the memory is hotplugged?

I think I'm missing something fundamental...

	-hpa

-- 
H. Peter Anvin, Intel Open Source Technology Center
I work for Intel.  I don't speak on their behalf.


  reply	other threads:[~2009-05-08  4:59 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-05-06 12:07 [PATCH] x86-64: improve e820_search_gap() Jan Beulich
2009-05-08  4:59 ` H. Peter Anvin [this message]
2009-05-08  6:40   ` Jan Beulich
2009-05-08 16:52     ` H. Peter Anvin
2009-05-08 19:22     ` Andi Kleen
2009-05-08 20:15       ` H. Peter Anvin
2009-05-08 20:53         ` Andi Kleen
2009-05-08 20:52           ` H. Peter Anvin
2009-05-09 10:00             ` Andi Kleen
2009-05-10  6:43               ` H. Peter Anvin
2009-05-10 15:18                 ` Andi Kleen
2009-05-10 17:56                   ` H. Peter Anvin
  -- strict thread matches above, loose matches on Subject: below --
2009-03-12 10:45 Jan Beulich
2009-03-12 11:02 ` Ingo Molnar
2009-03-12 11:31   ` Jan Beulich
2009-03-13 17:37 ` Jeremy Fitzhardinge

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