Re: [2.4.17/18pre] VM and swap - it's really unusable

[Helge Hafting]

Andrew Morton wrote:
[...]
> I haven't seen any figures for embedded XP, but it is said that
> if you bend over backwards you can get 10 milliseconds out of NT4,
> and 4-5 out of the fabled BeOS.  This is one area where we can
> fairly easily be very much the best.  It's low-hanging fruit.
> 
> Internal preemptability is, in my opinion, the best way to deliver
> this.
> 
> I accept your point about it making debugging harder - I would
> suggest that the preempt code be altered so that it can be disabled
> at runtime, rather than via a rebuild.  I suspect this can be
> done at zero cost by setting init_task's preempt count to 1000000
> via a kernel boot option.  And at almost-zero cost via a sysctl.

And with some bad luck, the bug goes away when you
do this.  The bug of the missing lock...

Helge Hafting