linux-kernel - Re: [PATCH 2/2] x86, boot: Optimize the elf header handling.

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Date:	Mon, 2 Jul 2012 09:56:33 -0700
From:	Tejun Heo <tj@...nel.org>
To:	"H. Peter Anvin" <hpa@...or.com>
Cc:	"Eric W. Biederman" <ebiederm@...ssion.com>,
	hacklu <embedway.linux@...il.com>, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 2/2] x86, boot: Optimize the elf header handling.

Hello, guys.

On Sun, Jul 01, 2012 at 11:37:22AM -0700, H. Peter Anvin wrote:
> If we don't need it, I think we can use -z max-page-size=4096, but we
> use the PMD alignment for percpu on x86-64; Tejun, does that apply to
> the .data..percpu section in the executable as well?

I don't think the .data..percpu section needs 2M alignment.  The
percpu data section is only used as init template and actual percpu
addresses always go through offsetting against __per_cpu_offset[] - no
matter what the vaddrs in the vmlinux are, they get offsetted into 2M
aligned linear address if necessary.  I think the only alignment
.data..percpu needs is cacheline alignment for separating its
subsections.

Thanks.

-- 
tejun
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