Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932325Ab0KVWhy (ORCPT ); Mon, 22 Nov 2010 17:37:54 -0500 Received: from mail-fx0-f46.google.com ([209.85.161.46]:46132 "EHLO mail-fx0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932281Ab0KVWhw (ORCPT ); Mon, 22 Nov 2010 17:37:52 -0500 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=message-id:date:from:user-agent:mime-version:to:cc:subject :references:in-reply-to:x-enigmail-version:content-type :content-transfer-encoding; b=gqDEI7DfGLOJb5ns8dvwXnjBlMnx9hZCWMYupJVZoZKNT9Qvc6YJ7DI9qsVlEJ9Y7R NU1DbEtXKg+YY3o9ml9NRSXP7F6jtjZKU+gJzXQBcdgbSwNemdQVUvD4V/Bm7Pplqu9r Hu0jOshLQTF/+Xf07kIoyvseoZcK35ur0I1jg= Message-ID: <4CEAF0B9.5020401@gmail.com> Date: Mon, 22 Nov 2010 23:37:45 +0100 From: Jiri Slaby User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; cs-CZ; rv:1.9.2.12) Gecko/20101026 SUSE/3.1.6 Thunderbird/3.1.6 MIME-Version: 1.0 To: Andreas Hartmann CC: linux-kernel@vger.kernel.org Subject: Re: missing 700 MB of RAM References: In-Reply-To: X-Enigmail-Version: 1.1.2 Content-Type: text/plain; charset=ISO-8859-15 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2809 Lines: 70 You should reply-to-all. On 11/22/2010 10:58 PM, Andreas Hartmann wrote: > Jiri Slaby wrote: >> On 11/21/2010 08:02 PM, Andreas Hartmann wrote: >>> I've got 8 GB RAM installed, but linux reports 7,3 GB. Where is the >>> missing RAM (700 MB)? >> ... >>> The motherboard is a GA-MA78GM-S2H (64bit, AMD) with a on board Radeon >>> HD 3200 VGA card. The card uses 256 MB of RAM - so 444 MB of RAM are >>> missing. Where are they gone? >> >> Hi, ask your BIOS: >> >>> BIOS-provided physical RAM map: >>> BIOS-e820: 0000000000000000 - 000000000009f800 (usable) >>> BIOS-e820: 000000000009f800 - 00000000000a0000 (reserved) >>> BIOS-e820: 00000000000f0000 - 0000000000100000 (reserved) >>> BIOS-e820: 0000000000100000 - 00000000afde0000 (usable) >>> BIOS-e820: 00000000afde0000 - 00000000afde3000 (ACPI NVS) >>> BIOS-e820: 00000000afde3000 - 00000000afdf0000 (ACPI data) >>> BIOS-e820: 00000000afdf0000 - 00000000afe00000 (reserved) >>> BIOS-e820: 00000000e0000000 - 00000000f0000000 (reserved) >>> BIOS-e820: 00000000fec00000 - 0000000100000000 (reserved) >>> BIOS-e820: 0000000100000000 - 0000000230000000 (usable) >> >> It reports 7677M of usable mem. Or maybe your loader is cheating on you? >> I doubt so... > > Ok. That's right. Anyway, I'm wondering about the difference to free: > > total used free shared buffers cached > Mem: 7706580 5271096 2435484 0 79232 3049120 > > which is 7526M. This means, there are missing 151M of usable RAM?! Yes, and if you look into dmesg, you will see: Your BIOS doesn't leave a aperture memory hole Please enable the IOMMU option in the BIOS setup This costs you 32 MB of RAM Mapping aperture over 32768 KB of RAM @ 20000000 Then there is some kernel code+data (11M), mem_map (108M) etc. 7677-108-32-11=7526 > I would have expected, that free reprots the same amount as the kernel > reports to be usable. > > On the other hand, I would have expected, that the amount, reported by > free + gfx-memory should nearly be 8 GB. Here it is: 7782. Thus there > are missing 410 MB between the installed hardware and free + gfx-memory. Since the BIOS is not reporting the memory, kernel can do only a little about that. > Removing the difference between free and physical ram map (410 - 151), > ~259 MB are remaing. This is nearly the amount for the gfx-card, which > has already been removed. Could it be, that the gfx-memory is reserved > twice - once by the bios and another time by the kernel?! I don't understand where you got the numbers... regards, -- js -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/