Re: vmpage01 patch - replace hash table and memq list with RB tree.

["Sepherosa Ziehau" <sepherosa@gmail.com>]

On 11/21/06, Matthew Dillon <dillon@apollo.backplane.com> wrote:
>     This is slated for commit on Friday.  This patch removes the global
>     VM page hash table and also removes the VM object memq for VM pages
>     and replaces them with a single red-black tree based in the VM object.
>     It needs some testing.
>
>         fetch http://apollo.backplane.com/DFlyMisc/vmpage01.patch
>
>     The work also takes advantage of the RB tree topology to remove a
>     number of hacks that previously existed to optimize page ranges.  The
>     new scheme is a much better fit to the types of ranged operations
>     we already perform and intend to perform in the future.
>     Lookups are somewhat less optimal and may inspire an optimization
>     later on, but the nerf isn't really noticeable.
>
>     One interesting outcome is that not having to allocate a global VM
>     page hash table also saves us about 1 megabyte of memory per gigabyte
>     of ram.  Ok, it isn't that much, but it's always nice to occassionally
>     be able to shrink the kernel's memory footprint :-)

Runs fine here, I have kept copying large files from/to the testing
machine, everything seems ok in last 12hours.

Cheers,
sephe

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