From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail137.messagelabs.com (mail137.messagelabs.com [216.82.249.19]) by kanga.kvack.org (Postfix) with SMTP id 6C7116B006A for ; Tue, 19 Jan 2010 17:02:50 -0500 (EST) Received: by fg-out-1718.google.com with SMTP id 22so535167fge.8 for ; Tue, 19 Jan 2010 14:02:48 -0800 (PST) Message-ID: <4B562C05.6080404@gmail.com> Date: Tue, 19 Jan 2010 23:02:45 +0100 From: Jiri Slaby MIME-Version: 1.0 Subject: Re: [RFC 1/1] bootmem: move big allocations behing 4G References: <1263855390-32497-1-git-send-email-jslaby@suse.cz> <20100119143355.GB7932@cmpxchg.org> In-Reply-To: <20100119143355.GB7932@cmpxchg.org> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org To: Johannes Weiner Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Ralf Baechle , x86@kernel.org List-ID: On 01/19/2010 03:33 PM, Johannes Weiner wrote: > On Mon, Jan 18, 2010 at 11:56:30PM +0100, Jiri Slaby wrote: >> Hi, I'm fighting a bug where Grub loads the kernel just fine, whereas >> isolinux doesn't. I found out, it's due to different addresses of >> loaded initrd. On a machine with 128G of memory, grub loads the >> initrd at 895M in our case and flat mem_map (2G long) is allocated >> above 4G due to 2-4G BIOS reservation. >> >> On the other hand, with isolinux, the 0-2G is free and mem_map is >> placed there leaving no space for others, hence kernel panics for >> swiotlb which needs to be below 4G. > > Bootmem already protects the lower 16MB DMA zone for the obvious reasons, > how about shifting the default bootmem goal above the DMA32 zone if it exists? Hi, I think it makes sense. > I tested the below on a rather dull x86_64 machine and it seems to work. Would > this work in your case as well? The goal for mem_map should now be above 4G. It seems that it will. I'll give it a try later (it needs to be set up) and report back. > From 1c11ce1e82c6209f0eda72e3340ab0c55cd6f330 Mon Sep 17 00:00:00 2001 > From: Johannes Weiner > Date: Tue, 19 Jan 2010 14:14:44 +0100 > Subject: [patch] bootmem: avoid DMA32 zone, if any, by default > > x86_64 and mips define a DMA32 zone additionally to the old DMA > zone of 16MB. Bootmem already avoids the old DMA zone if the > allocation site did not request otherwise. > > But since DMA32 is also a limited resource, avoid using it as well > by default, if defined. > > Signed-off-by: Johannes Weiner So for the time being: Reviewed-by: Jiri Slaby thanks, -- js -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org