On Thu, 28 Jan 2021, David Hildenbrand wrote: > diff --git a/mm/vmstat.c b/mm/vmstat.c > index 7758486097f9..957680db41fa 100644 > --- a/mm/vmstat.c > +++ b/mm/vmstat.c > @@ -1650,6 +1650,11 @@ static void zoneinfo_show_print(struct seq_file *m, pg_data_t *pgdat, > zone->spanned_pages, > zone->present_pages, > zone_managed_pages(zone)); > +#ifdef CONFIG_CMA > + seq_printf(m, > + "\n cma %lu", > + zone->cma_pages); > +#endif > > seq_printf(m, > "\n protection: (%ld", Hmm, not sure about this. If cma is only printed for CONFIG_CMA, we can't distinguish between (1) a kernel without your patch without including some version checking and (2) a kernel without CONFIG_CMA enabled. IOW, "cma 0" carries value: we know immediately that we do not have any CMA pages on this zone, period. /proc/zoneinfo is also not known for its conciseness so I think printing "cma 0" even for !CONFIG_CMA is helpful :) I think this #ifdef should be removed and it should call into a zone_cma_pages(struct zone *zone) which returns 0UL if disabled.
