'Change the vm_map lookup algorithm'
dillon at apollo.backplane.com
Sun Oct 3 16:13:29 PDT 2010
#1 on my list of things that can make the system faster now would be
how to MP-lock the VM system.
The problem the VM system has is that there is a billion different ways
to drill down into it. Via the filesystem buffer cache, via VM objects,
via the pmap (pmap->pte->vm_page), via pv_entry's in the pmap,
via VM pages, via the vm_map... those are the main ones.
So what we need to do is to come up with a way to MP lock the VM system
that is more fine-grained than our current vm_token but which allows
the above various methods to be implemented without having to acquire
tons of different locks on the way down.
This will bear a strong relationship to whatever indexing mechanic is
chosen for vm_map's, and perhaps also vm_object's which currently use
a RB tree as well (vm_object->rb_memq and vm_object->swblock_root).
<dillon at backplane.com>
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