From mboxrd@z Thu Jan 1 00:00:00 1970 From: "H. Peter Anvin" Subject: Re: [PATCH] Prevent reserving RAM in the region already reserved by BIOS Date: Wed, 19 May 2010 10:43:57 -0700 Message-ID: <4BF4235D.3080904@zytor.com> References: <4BF42296.1030905@oracle.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: Received: from terminus.zytor.com ([198.137.202.10]:37172 "EHLO mail.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753523Ab0ESRoS (ORCPT ); Wed, 19 May 2010 13:44:18 -0400 In-Reply-To: <4BF42296.1030905@oracle.com> Sender: linux-arch-owner@vger.kernel.org List-ID: To: Yinghai Cc: Mathieu Rondonneau , linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, Ingo Molnar , Linus Torvalds On 05/19/2010 10:40 AM, Yinghai wrote: > On 05/18/2010 10:35 PM, Mathieu Rondonneau wrote: >> Does it make sense to prevent looking for stolen RAM below the ISA section. >> >> >> Signed-off-by: Mathieu Rondonneau >> --- >> arch/x86/kernel/e820.c | 2 ++ >> 1 files changed, 2 insertions(+), 0 deletions(-) >> >> diff --git a/arch/x86/kernel/e820.c b/arch/x86/kernel/e820.c >> index 7bca3c6..322c9c3 100644 >> --- a/arch/x86/kernel/e820.c >> +++ b/arch/x86/kernel/e820.c >> @@ -1156,6 +1156,8 @@ void __init e820_reserve_resources_late(void) >> end = MAX_RESOURCE_SIZE; >> if (start >= end) >> continue; >> + if (end < ISA_START_ADDRESS) >> + continue; >> printk(KERN_DEBUG "reserve RAM buffer: %016llx - %016llx ", >> start, end); >> reserve_region_with_split(&iomem_resource, start, end, > > do you notice any changes in /proc/iomem? > It should be harmless to reserve memory which is already reserved, so this patch is at best a no-op. Furthermore, it introduces another instance of special address space (ISA_START_ADDRESS in this case) which is never a good thing. -hpa