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From: "H. Peter Anvin" <hpa@zytor.com>
To: Yinghai Lu <yhlu.kernel@gmail.com>
Cc: Andi Kleen <andi@firstfloor.org>,
	Jesse Barnes <jbarnes@virtuousgeek.org>,
	linux-pci@atrey.karlin.mff.cuni.cz, TJ <linux@tjworld.net>,
	Ingo Molnar <mingo@elte.hu>, Thomas Gleixner <tglx@linutronix.de>,
	linux-kernel <linux-kernel@vger.kernel.org>
Subject: Re: Why such a big difference in init-time PCI resource call-paths (x86 vs x86_64) ?
Date: Thu, 01 May 2008 14:11:50 -0700	[thread overview]
Message-ID: <481A3216.9030705@zytor.com> (raw)
In-Reply-To: <86802c440805011410q17c24653l292ccb6dad211a06@mail.gmail.com>

Yinghai Lu wrote:
> On Thu, May 1, 2008 at 1:11 PM, Andi Kleen <andi@firstfloor.org> wrote:
>> On Thu, May 01, 2008 at 11:16:31AM -0700, Jesse Barnes wrote:
>>  > On Wednesday, April 30, 2008 9:07 am TJ wrote:
>>  > > In preparation for writing a Windows-style PCI resource allocation
>>  > > strategy
>>  > >
>>  > >  - use all e820 gaps for IOMEM resources; top-down allocation -
>>  > >
>>  > > and thus giving devices with large IOMEM requirements more chance of
>>  > > allocation in the 32-bit address space below 4GB (see bugzilla #10461),
>>
>>  I tried that some time ago and it turned out that some systems have
>>  mappings in holes and don't boot anymore when you fill the holes too much.
>>  But that was only considering e820. if you do this it might work if you
>>  do it really like windows and consider all resources, including ACPI.
> 
> wonder if using holes in MTRR AND e820 could help...
> 

Typically not, since the MTRRs won't tell you what is free address space 
and what is occupied by non-BAR I/O devices.

	-hpa

  reply	other threads:[~2008-05-01 21:12 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <1209571638.25051.54.camel@hephaestion.lan.tjworld.net>
2008-05-01 18:16 ` Why such a big difference in init-time PCI resource call-paths (x86 vs x86_64) ? Jesse Barnes
2008-05-01 20:11   ` Andi Kleen
2008-05-01 20:11     ` H. Peter Anvin
2008-05-01 20:29       ` Jesse Barnes
2008-05-01 21:10     ` Yinghai Lu
2008-05-01 21:11       ` H. Peter Anvin [this message]
     [not found] <fa.GFIas4KVpQq9pUpviRWeT8L+oBs@ifi.uio.no>
     [not found] ` <fa.hdrruKIvW+GZA0AESo+nBXNURSA@ifi.uio.no>
     [not found]   ` <fa.9Qhgua9PuRzPYMHNs+ZG5Q7/Hbg@ifi.uio.no>
     [not found]     ` <fa.sQSbKD/rf/mnDK28NkngvUl4UA8@ifi.uio.no>
2008-05-02  5:03       ` Robert Hancock
2008-05-02  5:01         ` H. Peter Anvin
2008-05-02  8:03         ` Andi Kleen

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