Re: [PATCH 20/20] Get rid of the concept of hot/cold page freeing

Nick Piggin
2009-02-27T11:33:49Z

On Thu, Feb 26, 2009 at 12:30:45PM -0500, Christoph Lameter wrote:
> On Thu, 26 Feb 2009, Mel Gorman wrote:
>
> > > I tried the general use of a pool of zeroed pages back in 2005. Zeroing
> > > made sense only if the code allocating the page did not immediately touch
> > > the cachelines of the page.
> >
> > Any feeling as to how often this was the case?
>
> Not often enough to justify the merging of my patches at the time. This
> was publicly discussed on lkml:
>
> http://lkml.indiana.edu/hypermail/linux/kernel/0503.2/0482.html
>
> > Indeed, any gain if it existed would be avoiding zeroing the pages used
> > by userspace. The cleanup would be reducing the amount of
> > architecture-specific code.
> >
> > I reckon it's worth an investigate but there is still other lower-lying
> > fruit.
>
> I hope we can get rid of various ugly elements of the quicklists if the
> page allocator would offer some sort of support. I would think that the

Only if it provides significant advantages over existing quicklists or
adds *no* extra overhead to the page allocator common cases. :)