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From: Roland Dreier <rdreier@cisco.com>
To: "James Kirin" <james.kirin40@gmail.com>
Cc: linux-kernel@vger.kernel.org
Subject: Re: memory beyond4GB invisible to the system even though CONFIG_HIGHMEM64G=y
Date: Tue, 13 Jan 2009 18:22:19 -0800	[thread overview]
Message-ID: <adaeiz6k4o4.fsf@cisco.com> (raw)
In-Reply-To: <baeb34bc0901131746n33cd536co331e32361df2fb72@mail.gmail.com> (James Kirin's message of "Wed, 14 Jan 2009 01:46:33 +0000")

 > I am running kernel 2.6.28 on a computer with 8GB RAM. The BIOS
 > detects all 8GB, yet
 > 
 > jk@as12:~$ free
 >              total       used       free     shared    buffers     cached
 > Mem:       3622504     799696    2822808          0      90936     369604
 > -/+ buffers/cache:     339156    3283348
 > Swap:      6867776          0    6867776

The message in your kernel log:

[    0.000000] WARNING: BIOS bug: CPU MTRRs don't cover all of memory, losing 4096MB of RAM.
[    0.000000] ------------[ cut here ]------------
[    0.000000] WARNING: at arch/x86/kernel/cpu/mtrr/main.c:1662 mtrr_trim_uncached_memory+0x283/0x2a4()

is a clue.  You might want to look for a BIOS update for your
motherboard.

 - R.

  reply	other threads:[~2009-01-14  2:22 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-01-14  1:46 memory beyond4GB invisible to the system even though CONFIG_HIGHMEM64G=y James Kirin
2009-01-14  2:22 ` Roland Dreier [this message]
2009-01-14  3:10   ` James Kirin
2009-01-14  6:07     ` Yinghai Lu
2009-01-14 16:14       ` Roland Dreier
2009-01-14 18:16         ` Yinghai Lu
2009-01-15 19:50       ` James Kirin
2009-01-15 20:35         ` James Kirin
2009-01-15 20:45           ` Yinghai Lu
2009-01-15 20:51         ` Yinghai Lu

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