[Lguest] [PATCH RFC/RFB] x86_64, i386: interrupt dispatch changes

[Andi Kleen]

On Tue, Nov 04, 2008 at 12:26:13PM -0800, H. Peter Anvin wrote:
> Andi Kleen wrote:
> > 
> > Or again just generate them on demand when the interrupt is set up.
> > If you really have 240 interrupts sources you can afford the 5k likely,
> > but for most there will be only a minimum number of stubs.
> > 
> > Although frankly I suspect there are far easier ways to save 5k of memory.
> > 
> 
> Generating them dynamically is probably pretty ugly too, though.

Why? The only slightly tricky thing is that they need to be in no NX space.
Then it's just a few bytes patched in a template.

> Shrinking the whole table down to 2K by just regularizing the structure
> is trivial, though, and should almost certainly be a win.  The more
> esoteric ideas are probably worse.

Just think how much memory you could safe elsewhere with the same
effort.

-Andi