Re: [PATCH 7/9] mm: Add deferred_list page flag

[Matthew Wilcox <willy@infradead.org>]

On Tue, Aug 15, 2023 at 09:54:36AM +0200, David Hildenbrand wrote:
> On 15.08.23 05:26, Matthew Wilcox (Oracle) wrote:
> > Stored in the first tail page's flags, this flag replaces the destructor.
> > That removes the last of the destructors, so remove all references to
> > folio_dtor and compound_dtor.
> > 
> > Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
> > ---
> 
> [...]
> 
> > +	/* Has a deferred list (may be empty).  First tail page. */
> > +	PG_deferred_list = PG_reclaim,
> > +
> 
> If PG_deferred_list implies thp (and replaces the thp dtor), should we
> rather name this PG_thp or something along those lines?

We're trying to use 'thp' to mean 'a folio which is pmd mappable',
so I'd rather not call it that.

> The sequence of
> 
> 	if (folio_test_deferred_list(folio))
> 		free_transhuge_folio(folio);
> 
> Looks less clear to what we had before.

I can rename that.  How about

	if (folio_test_deferred_list(folio))
		folio_remove_deferred(folio);