Re: [PATCH v2] mm: Optimise put_pages_list()

[Matthew Wilcox]

On Thu, Oct 07, 2021 at 04:35:54PM -0700, Andrew Morton wrote:
> On Thu, 7 Oct 2021 21:55:21 +0100 Matthew Wilcox <willy@xxxxxxxxxxxxx> wrote:
> > My first response is an appeal to authority -- release_pages() does
> > this same thing.  Only it takes an array, constructs a list and passes
> > that to put_unref_page_list().  So if that's slower (and lists _are_
> > slower than arrays), we should have a put_unref_page_array().
> 
> And put_unref_page_list() does two passes across the list!
> 
> <quietly sobs>
> 
> Here is my beautiful release_pages(), as disrtibuted in linux-2.5.33:

I think that looks much better!

> I guess the current version is some commentary on the aging process?

I blame the guy who sent cc59850ef940 to Linus back in 2011 ...

I think Anthony was going to look into this and perhaps revert us to
a pagevec_free() interface.