On 07/09/2014 10:13 AM, Mel Gorman wrote: > --- a/mm/page_alloc.c > +++ b/mm/page_alloc.c > @@ -1604,6 +1604,9 @@ again: > } > > __mod_zone_page_state(zone, NR_ALLOC_BATCH, -(1 << order)); This can underflow zero, right? > + if (zone_page_state(zone, NR_ALLOC_BATCH) == 0 && AFAICS, zone_page_state will correct negative values to zero only for CONFIG_SMP. Won't this check be broken on !CONFIG_SMP? I just stumbled upon this when trying to optimize the function. I didn't check how rest of the design copes with negative NR_ALLOC_BATCH values. > + !zone_is_fair_depleted(zone)) > + zone_set_flag(zone, ZONE_FAIR_DEPLETED); > > __count_zone_vm_events(PGALLOC, zone, 1 << order); > zone_statistics(preferred_zone, zone, gfp_flags); > @@ -1915,6 +1918,18 @@ static bool zone_allows_reclaim(struct zone *local_zone, struct zone *zone) > > #endif /* CONFIG_NUMA */ > -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>