Re: [tip:sched/numa] mm/mpol: Lazy migrate a process/vma

[Andi Kleen <andi@xxxxxxxxxxxxxx>]

tip-bot for Peter Zijlstra <a.p.zijlstra@xxxxxxxxx> writes:
> +
> +	/*
> +	 * Obtain a more-or-less correct nodemask to find which pages we need
> +	 * to unmap so that MoF can put them right again.
> +	 *
> +	 * Not quite correct for INTERLEAVE, that would need us doing
> +	 * offset_il_node() from check_pte_entry().
> +	 *
> +	 * Also not quite correct for task policies since we don't have a task,
> +	 * approximate by having @node function as local / task-home-node.

Hmm, so this destroys existing numa policies for already running processes?

Andrea's original THP had a similar problem, and it caused serious
performance problems before it was fixed.

I also seem to miss the benchmark numbers justifying all that code.

-Andi

-- 
ak@xxxxxxxxxxxxxxx -- Speaking for myself only
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