Re: [PATCH RFC 0/2] kvm: Improving undercommit,overcommit scenariosin PLE handler

[Peter Zijlstra]

On Wed, 2012-09-26 at 15:20 +0200, Andrew Jones wrote:
> Wouldn't a clean solution be to promote a task's scheduler
> class to the spinner class when we PLE (or come from some special
> syscall
> for userspace spinlocks?)? 

Userspace spinlocks are typically employed to avoid syscalls..

> That class would be higher priority than the
> fair class and would schedule in FIFO order, but it would only run its
> tasks for short periods before switching. 

Since lock hold times aren't limited, esp. for things like userspace
'spin' locks, you've got a very good denial of service / opportunity for
abuse right there.


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