From: Nico Pache <npache@xxxxxxxxxx> Sent: Friday, March 14, 2025 2:38 PM > > Update the NR_BALLOON_PAGES counter when pages are added to or > removed from the Hyper-V balloon. > > Signed-off-by: Nico Pache <npache@xxxxxxxxxx> > --- > drivers/hv/hv_balloon.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/drivers/hv/hv_balloon.c b/drivers/hv/hv_balloon.c > index fec2f18679e3..2b4080e51f97 100644 > --- a/drivers/hv/hv_balloon.c > +++ b/drivers/hv/hv_balloon.c > @@ -1192,6 +1192,7 @@ static void free_balloon_pages(struct hv_dynmem_device *dm, > __ClearPageOffline(pg); > __free_page(pg); > dm->num_pages_ballooned--; > + mod_node_page_state(page_pgdat(pg), NR_BALLOON_PAGES, -1); > adjust_managed_page_count(pg, 1); > } > } > @@ -1221,6 +1222,7 @@ static unsigned int alloc_balloon_pages(struct hv_dynmem_device *dm, > return i * alloc_unit; > > dm->num_pages_ballooned += alloc_unit; > + mod_node_page_state(page_pgdat(pg), NR_BALLOON_PAGES, alloc_unit); > > /* > * If we allocatted 2M pages; split them so we > -- > 2.48.1 > As is evident from the code, the hv_balloon driver already has accounting for the number of pages that have been ballooned out of the VM. This accounting and other details of the hv_balloon driver state is available in /sys/kernel/debug/hv-balloon when CONFIG_DEBUGFS=y. But it seems OK to also report the # of pages ballooned through /proc/meminfo, which works even if CONFIG_DEBUGFS=n. Reviewed-by: Michael Kelley <mhklinux@xxxxxxxxxxx>
