Re: shared pagetable benchmarking

[Ingo Molnar <mingo@elte.hu>]

On Fri, 27 Dec 2002, Andrew Morton wrote:

> Yup.  Ingo said at the time:
> 
>   It would be faster to iterate the pagecache mapping's radix tree
>   and the pagetables at once, but it's also *much* more complex. I have
>   tried to implement it and had to unroll the change - mixing radix tree
>   walking and pagetable walking and getting all the VM details right is
>   really complex - especially considering all the re-lookup race checks
>   that have to occur upon IO.
> 
> But find_get_pages() is well-suited to this, and was not in place when
> he did this work.

i agree that find_get_pages() would simplify this work. I did not consider
group-lookup - i tried to implement an algorithm that had a single-page
scope, to keep the amount of locked pages to the minimum.

	Ingo

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