We already discussed in the past that we need a better and more efficient way to walk page tables. I have part of that on my TODO list, but I'm getting distracted.
Yes I remember an LSF session on this, it's a really obvious area of improvement that stands out at the moment for sure.
Having worked several 12+ hour days in a row though recently I can relate to workload making this difficult though :)
Yes :)
*Inserting* (not walking/modifying existing things as most users to) as done in this patch is slightly different though, likely "on thing that fits all" will not apply to all page table walker user cases.
Yeah, there's also replace scenarios which then have to do egregious amounts of work to make sure we do everything right, in fact there's duplicates of this in mm/madvise.c *grumble grumble*.
-- Cheers,
David / dhildenb
OK so I guess I'll hold off my TODOs on this as you are looking in this area and I trust you :)
It will probably take me a while until I get to it, though. I'd focus on walking (and batching what we can) first, then on top modifying existing entries.
The "install something where there is nothing yet" (incl. populating fresh page tables etc.) case probably deserves a separate "walker".
If you end up having spare cycles and want to sync on a possible design for some part of that bigger task -- removing the old pagewalk logic -- please do reach out! :)