Re: [patch 2/2] x86 NMI-safe INT3 and Page Fault

Mathieu Desnoyers
2010-07-16T15:40:28Z

* Andi Kleen (andi@firstfloor.org) wrote:
> > Well, it seems like all the kernel code calling "vmalloc_sync_all()" (which is
> > much more than perf) can potentially cause large latencies, which could be
>
> You need to fix all other code too that walks tasks lists to avoid all those.
>
> % gid for_each_process | wc -l

This can very well be done incrementally. And I agree, these should eventually
targeted too, especially those which hold locks. We've already started hearing
about tasklist lock live-locks in the past year, so I think we're pretty much at
the point where it should be looked at.

Thanks,

Mathieu

>
> In fact the mm-struct walk is cheaper than a task-list walk because there
> are always less than tasks.

--
Mathieu Desnoyers
Operating System Efficiency R&D Consultant
EfficiOS Inc.