Re: [PATCH] Radix-tree pagecache for 2.5

[Alan Cox]

> the prefetch engine will have to restart every 4kB, so we would want to
> use 16MB pages if possible.
> 
> How would we allocate large pages? Would there be a boot option to
> reserve an area of RAM for large pages only?

If you have an rmap all you have to do is to avoid smearing kernel objects
around lots of 16Mb page sets. If need be you can then get a 16Mb page
back just by shuffling user pages.

It does make the performance analysis much more interesting though.