linux-kernel - Re: [PATCH v3 5/5] Use 2GB memory block size on large x86-64 systems

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Message-ID: <alpine.DEB.2.11.1411040848090.5308@nanos>
Date:	Tue, 4 Nov 2014 08:50:50 +0100 (CET)
From:	Thomas Gleixner <tglx@...utronix.de>
To:	Daniel J Blueman <daniel@...ascale.com>
cc:	Ingo Molnar <mingo@...hat.com>, "H. Peter Anvin" <hpa@...or.com>,
	Bjorn Helgaas <bhelgaas@...gle.com>, x86@...nel.org,
	linux-kernel@...r.kernel.org, linux-pci@...r.kernel.org,
	Steffen Persvold <sp@...ascale.com>
Subject: Re: [PATCH v3 5/5] Use 2GB memory block size on large x86-64
 systems

On Tue, 4 Nov 2014, Daniel J Blueman wrote:
> On 11/04/2014 07:36 AM, Thomas Gleixner wrote:
> > On Tue, 4 Nov 2014, Daniel J Blueman wrote:
> > > > > @@ -1247,9 +1246,9 @@ static unsigned long
> > > > > probe_memory_block_size(void)
> > > > >    	/* start from 2g */
> > > > >    	unsigned long bz = 1UL<<31;
> > > > > 
> > > > > -#ifdef CONFIG_X86_UV
> > > > > -	if (is_uv_system()) {
> > > > > -		printk(KERN_INFO "UV: memory block size 2GB\n");
> > > > > +#ifdef CONFIG_X86_64
> > > > 
> > > > And this brainless 's/CONFIG_X86_UV/CONFIG_X86_64/' sucks even
> > > > more. I'm sure you can figure out the WHY yourself.
> > > 
> > > The benefit of this is applicable to other architectures. I'm unable to
> > > test
> > > the change, but if you agree it's conservative enough, I'll drop the
> > > ifdef?
> > 
> > Which other architectures? Care to turn on your brain before replying?
> 
> Clearly 64-bit architectures, including X86, MIPS, PARISC, SPARC, AArch64,
> ia64,

ROTFL

> however, I must be missing something, as a sizeof(long)/CONFIG_64BIT
> check would be redundant if we agree to drop the ifdef, as we're already
> checking the number of physical pages, which is bounded by the same limits.

# diffstat $this_patch

should precicely tell you what you're missing.

Thanks,

	tglx
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