linux-kernel - Disabling physical RAM regions for testing

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Message-ID: <20140805114010.GA14521@fishbowl.rw.madduck.net>
Date:	Tue, 5 Aug 2014 13:40:10 +0200
From:	martin f krafft <madduck@...duck.net>
To:	linux kernel mailing list <linux-kernel@...r.kernel.org>
Subject: Disabling physical RAM regions for testing

Hello,

A NAS seems to be having RAM problems, leading me to want to swap
out DIMMs until I found the offender; I'd rather not go to the rack
every time I need to make a change.

Is there a way to declare a DIMM unavailable to Linux with a boot
parameter? There is mem= and memmap= but i cannot figure them out.

I have two 4Gb DIMMs in there and I just want to disable one, then
the other…

This is the e820 physical RAM map:

[    0.000000] e820: BIOS-provided physical RAM map:
[    0.000000] BIOS-e820: [mem 0x0000000000000000-0x000000000009e7ff] usable
[    0.000000] BIOS-e820: [mem 0x000000000009e800-0x000000000009ffff] reserved
[    0.000000] BIOS-e820: [mem 0x00000000000e2000-0x00000000000fffff] reserved
[    0.000000] BIOS-e820: [mem 0x0000000000100000-0x00000000bff8ffff] usable
[    0.000000] BIOS-e820: [mem 0x00000000bff9e000-0x00000000bff9ffff] reserved
[    0.000000] BIOS-e820: [mem 0x00000000bffa0000-0x00000000bffaa5ff] ACPI data
[    0.000000] BIOS-e820: [mem 0x00000000bffaa600-0x00000000bffdffff] ACPI NVS
[    0.000000] BIOS-e820: [mem 0x00000000bffe0000-0x00000000bfffffff] reserved
[    0.000000] BIOS-e820: [mem 0x00000000e0000000-0x00000000efffffff] reserved
[    0.000000] BIOS-e820: [mem 0x00000000ffa00000-0x00000000ffffffff] reserved
[    0.000000] BIOS-e820: [mem 0x0000000100000000-0x000000022fffffff] usable

But what do I do with those info?

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