[PATCH] EXA: Defragment offscreen memory.

[Nix]

On 17 Feb 2009, Michel Dänzer said:
> On Sat, 2009-02-14 at 19:03 +0100, Michel Dänzer wrote:
>> It shouldn't be too expensive usually and will only actually run at
>> most once per second anyway, [...]
>
> Given this (and that 'Nix' hasn't complained about the BlockHandler
> overhead :), I'd suggest trying this, and if people complain about weird
> delays every second, we can reduce the frequency further or even remove
> the BlockHandler defragmentation run altogether. Sounds good?

Well, defragmenting once every 20ms seems kind of excessive to me, but I
suppose it won't have much to do in terms of bulk memory moves if the
server is idle.

I have noticed a slight increase in idle X server CPU consumption (it
eats about 5% of my Athlon's CPU now even if nothing is happening and
the screen is black), but compared to the immense amount that merely
scrolling guzzled before that is acceptable. I haven't noticed any
rendering delays though, so maybe the CPU load is coming from something
else.

(but still, it would be nice to fix. I'll give the server a profile
sometime and see where that black-screen load is coming from.)