[PATCH 1/5] mm: add PSI accounting around ->read_folio and ->readahead calls

[Matthew Wilcox]

On Sat, Sep 10, 2022 at 08:50:54AM +0200, Christoph Hellwig wrote:
> @@ -480,11 +487,14 @@ static inline int ra_alloc_folio(struct readahead_control *ractl, pgoff_t index,
>  	if (index == mark)
>  		folio_set_readahead(folio);
>  	err = filemap_add_folio(ractl->mapping, folio, index, gfp);
> -	if (err)
> +	if (err) {
>  		folio_put(folio);
> -	else
> -		ractl->_nr_pages += 1UL << order;
> -	return err;
> +		return err;
> +	}
> +
> +	ractl->_nr_pages += 1UL << order;
> +	ractl->_workingset = folio_test_workingset(folio);

I don't have time to look at this properly right now (about to catch a
bus to the plane), but I think this should be |=, not =?