Re: Page allocator: Single Zone optimizations

Christoph Lameter
2006-11-03T19:23:17Z

On Fri, 3 Nov 2006, Peter Zijlstra wrote:

> > IMHO Moving pages creates less collateral damage than evicting
> > random pages.
>
> Move them where?, you have to drop pages anyway, the only thing
> migrate_pages() (my bad for calling it move_pages()) might help with is
> preserving LRU order better and the possibility to move otherwise
> unreclaimable pages to a more favourable position (page-tables,
> mlock'ed).

If you do not have any memory left then we run reclaim to free pages.
We are dealing here with the issue that we have enough memory free but
it is not contiguous. So we have other places where we could put these
pages.