* Linus Torvalds <[email protected]> wrote:
> [...]
>
> No, I was thinking "try to optimistically map 8 adjacent aligned
> pages at a time" - that would be the same cacheline in the page
> tables, so it would be fairly cheap if we couple it with a
> gang-lookup of the pages in the page cache (or, for anonymous pages,
> by just optimistically trying to do an order-3 page allocation, and
> if that works, just map the 32kB allocation you got as eight
> individual pages).
>
> I know it's been discussed at some point, and I even have a dim
> memory of having seen some really ugly patches.
I have a dim memory of having written such group-prefaulting patches
myself a decade ago or so - IIRC the main problem was that at that
time we never found a common load where it really mattered, and it was
easy to spend more time doing all this extra work and not see the
prefaulted pages used.
But the cost/benefit balance has indeed changed so IMO it's worth a
try.
Thanks,
Ingo
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