It should be possible to prevent a user from hogging a system if the system's
naive scheduler is improved.
Amancio
> It is not possible to prevent a user from hogging the cpu on the system.
> What you *CAN* do is make it difficult for the user to crash the system
> by limiting the number of processes he is allowed to run, the maximum
> data segment size each process is allowed to allocate, and by placing
> quotas on disk partitions he has write access to. This allows a
> sysop to get on the system and blow the idiot user away without having
> to reboot.
>
> cpu utilization has nothing to do with system cpu verses user cpu. cpu
> is cpu. One process can hog the cpu, it doesn't really matter whether
> it is supervisor or user mode cpu. The system will attempt to balance
> cpu utilization when several processes need cpu. The worst a user can
> do cpu-wise is to start N cpu-bound processes.
>
> Starting N cpu-bound processes will drive the load up on the machine, but
> as long as N is limited it will not prevent a sysop from getting in there
> and taking out the user.
>
> You don't give user accounts away to people who you think might
> try to crash the system, so resource limits are mostly there to prevent
> users making stupid mistakes from taking the system down with them.
>
> -Matt
>
>
>
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