On Sat, Mar 13, 2021 at 12:37:07PM -0800, Andrew Morton wrote:

On Fri,  5 Mar 2021 04:18:39 +0000 "Matthew Wilcox (Oracle)" [off-list ref] wrote:

quoted

Allow page counters to be more readily modified by callers which have
a folio.  Name these wrappers with 'stat' instead of 'state' as requested
by Linus here:
https://lore.kernel.org/linux-mm/CAHk-=wj847SudR-kt+46fT3+xFFgiwpgThvm7DJWGdi4cVrbnQ@mail.gmail.com/ (local)

--- a/include/linux/vmstat.h
+++ b/include/linux/vmstat.h

@@ -402,6 +402,54 @@ static inline void drain_zonestat(struct zone *zone,
 			struct per_cpu_pageset *pset) { }
 #endif		/* CONFIG_SMP */
 
+static inline
+void __inc_zone_folio_stat(struct folio *folio, enum zone_stat_item item)
+{
+	__mod_zone_page_state(folio_zone(folio), item, folio_nr_pages(folio));
+}

The naming is unfortunate.  We expect

inc: add one to
dec: subtract one from
mod: modify by signed quantity

So these are inconsistent.  Perhaps use "add" and "sub" instead.  At
least to alert people to the fact that these are different.

And, again, it's nice to see the subsystem's name leading the
identifiers, so "zone_folio_stat_add()".

I thought this was a 'zone stat', so __zone_stat_add_folio()?
I'm not necessarily signing up to change the existing
__inc_node_page_state(), but I might.  If so, __node_stat_add_page()?