Re: 2.6.0-test9 - poor swap performance on low end machines

William Lee Irwin III
2003-12-11T01:28:48Z

On Wed, Dec 10, 2003 at 11:05:25PM +0100, Roger Luethi wrote:
>> Also, the 2.6 core VM doesn't seem all that bad since it was introduced in
>> 2.5.27 but most of the problems I measured were introduced after 2.5.40.
>> Check out the graph I posted.

On Wed, Dec 10, 2003 at 11:44:46PM +0100, Andrea Arcangeli wrote:
> you're confusing rmap with core vm. rmap in no way can be defined as the
> core vm, rmap is just a method used by the core vm to find some
> information more efficiently at the expenses of all the fast paths
> that now have to do the rmap bookkeeping.

I've been maintaining one of the answers to this (anobjrmap, originally
from hugh). I still haven't removed page->mapcount because keeping
nr_mapped straight requires some care, though doing so should be feasible.

I could probably use some helpers to untangle it from the highpmd,
compile-time mapping->page_lock rwlock/spinlock switching, RCU
mapping->i_shared_lock, and O(1) proc_pid_statm() bits.

-- wli