Re: [PATCH 1/2] mm/readahead: stop readahead loop if memcg charge fails

[Matthew Wilcox]

On Thu, Feb 01, 2024 at 06:08:34PM +0800, Liu Shixin wrote:
> @@ -247,9 +248,12 @@ void page_cache_ra_unbounded(struct readahead_control *ractl,
>  		folio = filemap_alloc_folio(gfp_mask, 0);
>  		if (!folio)
>  			break;
> -		if (filemap_add_folio(mapping, folio, index + i,
> -					gfp_mask) < 0) {
> +
> +		ret = filemap_add_folio(mapping, folio, index + i, gfp_mask);
> +		if (ret < 0) {
>  			folio_put(folio);
> +			if (ret == -ENOMEM)
> +				break;

No, that's too early.  You've still got a batch of pages which were
successfully added; you have to read them.  You were only off by one
line though ;-)

>  			read_pages(ractl);
>  			ractl->_index++;
>  			i = ractl->_index + ractl->_nr_pages - index - 1;
> -- 
> 2.25.1
> 
>