linux-kernel - Re: [PATCH] x86_64 vDSO: use initdata

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Date:	Mon, 28 Apr 2008 15:14:08 +0200
From:	Ingo Molnar <mingo@...e.hu>
To:	Roland McGrath <roland@...hat.com>
Cc:	Thomas Gleixner <tglx@...utronix.de>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH] x86_64 vDSO: use initdata


* Roland McGrath <roland@...hat.com> wrote:

> The 64-bit vDSO image is in a special ".vdso" section for no reason I 
> can determine.  Furthermore, the location of the vdso_end symbol 
> includes some wrongly-calculated padding space in the image, which is 
> then (correctly) rounded to page size, resulting in an extra page of 
> zeros in the image mapped in to user processes.
> 
> This changes it to put the vdso.so image into normal initdata as we 
> have always done for the 32-bit vDSO images.  The extra padding is 
> gone, so the user VMA is one page instead of two.  The image that was 
> already copied around at boot time is now in initdata, so we recover 
> that wasted space after boot.

thanks Roland, applied. I suspect this will need a few days of test-time 
as we change the user-space vma layout. (not in material ways though)

	Ingo
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