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SubjectRe: Weightless process class
Hi!

> A process can't grab a kernel lock and then switch
> back to user mode, can it? (if it could, I can
> imagine some nasty DoS attacks...)
>
> Problem is, when we decide to schedule in a process
> or not, we know the process was last stuck in
> schedule() ... in kernel mode ;(
>
> I'd love to be proven wrong though ... this would be
> some extremely useful functionality ;)

There was solution to it: bumping priority to normal when process is
in kernel. Hard part was how to do it with 0 impact on normal kernel
operation, and even that was solved (as you are testing for ptrace,
anyway, you can make it test for extremely-low-prio in same assembly
instruction).
Pavel
--
The best software in life is free (not shareware)! Pavel
GCM d? s-: !g p?:+ au- a--@ w+ v- C++@ UL+++ L++ N++ E++ W--- M- Y- R+
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