From: Arne Georg Gleditsch <arne.gleditsch@dolphinics.no>
To: Andi Kleen <andi@firstfloor.org>
Cc: Zhao Forrest <forrest.zhao@gmail.com>,
discuss@x86-64.org, linux-kernel@vger.kernel.org,
yhlu.kernel@gmail.com, mingo@elte.hu
Subject: Re: Does Linux have plan to support memory hole remapping?
Date: Wed, 09 Apr 2008 12:16:20 +0200 [thread overview]
Message-ID: <kjmk5j7xrij.fsf@pelargir.dolphinics.no> (raw)
In-Reply-To: <20080409100331.GH19010@one.firstfloor.org> (Andi Kleen's message of "Wed, 9 Apr 2008 12:03:31 +0200")
Andi Kleen <andi@firstfloor.org> writes:
> On Wed, Apr 09, 2008 at 11:50:00AM +0200, Arne Georg Gleditsch wrote:
>> Hm, wouldn't the given e820 map and mtrr listing indicate that 512M were
>> actually remapped to 32G+ in this case?
>
> The way it usually works (if it is implemented correctly in the BIOS)
> is that all memory starting at the hole moves up together
> (often subject to DIMM boundaries etc.),
> not that the area below the hole is remapped individually.
Yes, bad choice of words on my part.
> BTW it is not actually 512MB that is lost. MemTotal does not
> include mem_map and that alone is ~512MB (64 bytes for each 4K page)
>
> So as far as I can see there is no missing memory remapping in Zhao's case,
> he's just confused by the MemTotal semantics.
...meaning that upgrading his BIOS isn't going to change anything for
him, which is what I suspected from the e820 readouts.
--
Arne.
next prev parent reply other threads:[~2008-04-09 10:16 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-04-09 7:54 Zhao Forrest
2008-04-09 8:01 ` Andi Kleen
2008-04-09 8:37 ` Matti Aarnio
2008-04-09 8:49 ` Andi Kleen
2008-04-09 8:54 ` Ingo Molnar
2008-04-09 9:03 ` Andi Kleen
2008-04-10 0:34 ` Kasper Sandberg
2008-04-10 2:09 ` H. Peter Anvin
2008-04-10 12:41 ` Kasper Sandberg
2008-04-10 6:51 ` Andi Kleen
2008-04-09 9:04 ` Zhao Forrest
2008-04-09 9:13 ` Andi Kleen
2008-04-10 6:51 ` Zhao Forrest
2008-04-10 7:22 ` Andi Kleen
2008-04-09 9:50 ` Arne Georg Gleditsch
2008-04-09 10:03 ` Andi Kleen
2008-04-09 10:16 ` Arne Georg Gleditsch [this message]
2008-04-09 18:02 ` Yinghai Lu
2008-04-09 13:34 ` Lennart Sorensen
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