Re: [lockup] Re: objrmap-core-1 (rmap removal for file mappings to avoid 4:4 in <=16G machines)

Andrea Arcangeli
2004-03-09T17:56:12Z

On Tue, Mar 09, 2004 at 12:22:07PM -0500, Rik van Riel wrote:
> Andrea may want to try a kd-tree instead of the linked
> lists, that could well fix the problem you're running
> into.

Yep.

Martin's idea of splitting the i_mmap into a multiple lists each
covering a certain range is one of those possibilities to make objrmap
scale.

We've lot of room for improvements.

The basic idea of objrmap vs rmap is that one single object (the vma)
allows us to index tons and tons of ptes, instead of requiring a per-pte
overhead of the pte_chains.

Right now we're not very efficient in finding the "interesting vmas"
especially for file mappings, but we can make that more finegrined over
time. For the anon_vmas work I'm doing that's already quite well
finegriend since it's like if they belong all to different inodes so the
problem is minor there.