Re: [PATCH v3 00/21] huge page clearing optimizations

[Matthew Wilcox]

On Wed, Jun 08, 2022 at 08:49:57PM +0100, Matthew Wilcox wrote:
> On Tue, Jun 07, 2022 at 10:56:01AM -0700, Linus Torvalds wrote:
> > I worry a bit about the insanity of the "gigantic" pages, and the
> > mem_map_next() games it plays, but that code is from 2008 and I really
> > doubt it makes any sense to keep around at least for x86. The source
> > of that abomination is powerpc, and I do not think that whole issue
> > with MAX_ORDER_NR_PAGES makes any difference on x86, at least.
> 
> Oh, argh, I meant to delete mem_map_next(), and forgot.
> 
> If you need to use struct page (a later message hints you don't), just
> use nth_page() directly.  I optimised it so it's not painful except on
> SPARSEMEM && !SPARSEMEM_VMEMMAP back in December in commit 659508f9c936.
> And nobody cares about performance on SPARSEMEM && !SPARSEMEM_VMEMMAP
> systems.

Oops, wrong commit.  I meant 1cfcee728391 from June 2021.