Re: [PATCH rfc 4/4] mm: filemap: try to batch lruvec stat updating

[Johannes Weiner <hannes@cmpxchg.org>]

On Tue, May 07, 2024 at 05:06:57PM +0800, Kefeng Wang wrote:
> > +static void filemap_lruvec_stat_update(struct mem_cgroup *memcg,
> > +				       pg_data_t *pgdat, int nr)
> > +{
> > +	struct lruvec *lruvec;
> > +
> > +	if (!memcg) {
> > +		__mod_node_page_state(pgdat, NR_FILE_MAPPED, nr);
> > +		return;
> > +	}
> > +
> > +	lruvec = mem_cgroup_lruvec(memcg, pgdat);
> > +	__mod_lruvec_state(lruvec, NR_FILE_MAPPED, nr);
> > +}
> > +
> >   vm_fault_t filemap_map_pages(struct vm_fault *vmf,
> >   			     pgoff_t start_pgoff, pgoff_t end_pgoff)
> >   {
> > @@ -3628,6 +3642,9 @@ vm_fault_t filemap_map_pages(struct vm_fault *vmf,
> >   	vm_fault_t ret = 0;
> >   	unsigned long rss = 0;
> >   	unsigned int nr_pages = 0, mmap_miss = 0, mmap_miss_saved, folio_type;
> > +	struct mem_cgroup *memcg, *memcg_cur;
> > +	pg_data_t *pgdat, *pgdat_cur;
> > +	int nr_mapped = 0;
> >   
> >   	rcu_read_lock();
> >   	folio = next_uptodate_folio(&xas, mapping, end_pgoff);
> > @@ -3648,9 +3665,20 @@ vm_fault_t filemap_map_pages(struct vm_fault *vmf,
> >   	}
> >   
> >   	folio_type = mm_counter_file(folio);
> > +	memcg = folio_memcg(folio);
> > +	pgdat = folio_pgdat(folio);

You should be able to do:

	lruvec = folio_lruvec(folio);

and then pass that directly to filemap_lruvec_stat_update().