Re: [PATCH v2 36/46] mm/filemap: Add readahead_folio()

[Matthew Wilcox]

On Wed, Jun 23, 2021 at 11:50:04AM +0200, Christoph Hellwig wrote:
> On Tue, Jun 22, 2021 at 01:15:41PM +0100, Matthew Wilcox (Oracle) wrote:
> > The pointers stored in the page cache are folios, by definition.
> > This change comes with a behaviour change -- callers of readahead_folio()
> > are no longer required to put the page reference themselves.  This matches
> > how readpage works, rather than matching how readpages used to work.
> 
> The way this stores and retrieves different but compatible types from the
> same xarray is a little nasty.  But I guess we'll have to live with it for
> now, so:

I think that's mostly fixed up by the end of this series.  I think
there's still a few bits which are currently postponed to series 4
(eg uses of __page_cache_alloc followed by add_to_page_cache_lru).

> Reviewed-by: Christoph Hellwig <hch@xxxxxx>