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From: "H. Peter Anvin" <hpa@zytor.com>
To: Andi Kleen <andi@firstfloor.org>
Cc: Jan Beulich <jbeulich@novell.com>,
	mingo@elte.hu, tglx@linutronix.de, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] x86-64: improve e820_search_gap()
Date: Fri, 08 May 2009 13:52:41 -0700	[thread overview]
Message-ID: <4A049B99.4000402@zytor.com> (raw)
In-Reply-To: <20090508205347.GC23223@one.firstfloor.org>

Andi Kleen wrote:
> On Fri, May 08, 2009 at 01:15:38PM -0700, H. Peter Anvin wrote:
>> Andi Kleen wrote:
>>> "Jan Beulich" <jbeulich@novell.com> writes:
>>>> Why blindly? Aren't hotpluggable memory ranges supposed to be reserved
>>>> in the E820 map?
>>> They are supposed to be reserved in SRAT, but not in e820.
>> Ah, okay.  Perhaps we should fold this information into our internal 
>> "e820" map?  If so I guess the question is how soon we can do that.
> 
> You could do that or just query SRAT too, but ...
> 
> The problem is really that there are still systems which have hidden
> holes which are not reserved anywhere. When I last hacked on the gap algorithm
> it triggered subtle bugs. So this will never be fully reliable.
> 

That's without a question.

However, as far as querying SRAT, I don't like the idea of spreading the 
knowledge of the system memory map out between a bunch of different 
places, each of which have a little piece of the puzzle.  It puts a huge 
onus on the user to know what mechanisms are actually available, and 
really makes a shitty interface.

	-hpa

  reply	other threads:[~2009-05-08 20:53 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
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 [this message]
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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