Date: Wed, 19 Mar 2008 09:32:28 +0100
From: Andi Kleen <andi@firstfloor.org>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Andi Kleen <andi@firstfloor.org>, linux-kernel@vger.kernel.org,
       linux-mm@kvack.org
Subject: Re: [PATCH prototype] [0/8] Predictive bitmaps for ELF executables
Message-ID: <20080319083228.GM11966@one.firstfloor.org>
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On Tue, Mar 18, 2008 at 10:44:37AM -0700, Andrew Morton wrote:
> On Tue, 18 Mar 2008 18:20:45 +0100 Andi Kleen <andi@firstfloor.org> wrote:
> 
> > > What's the permission problem?  executable-but-not-readable files?  Could
> > 
> > Not writable. 
> 
> Oh.
> 
> I doubt if a userspace implementation would even try to alter the ELF
> files, really - there seems to be no point in it.   This is just complexity

Well the information has to be somewhere and i think the ELF file
is the best location for it. It makes it the most user transparent.

> > Yes it could, but i dont even want to thi nk about all the issues of
> > doing such an interface. It is basically an microkernelish approach.
> > I prefer monolithic simplicity.
> 
> It's not complex at all.  Pass a null-terminated pathname to the server and
> keep running.  The server will asynchronously read your pages for you.

But how do you update the bitmap in your scheme? 

> > And I am really not a friend of unnecessary complexity. In the end
> > complexity hurts you, no matter if it is in ring 3 or ring 0.
> 
> There is no complexity here.

I have my doubts on that if you consider update too.

-Andi
> 
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