On Tue 08-08-17 14:34:25, Wei Wang wrote: > On 08/08/2017 02:12 PM, Wei Wang wrote: > >On 08/03/2017 05:11 PM, Michal Hocko wrote: > >>On Thu 03-08-17 14:38:18, Wei Wang wrote: > >>This is just too ugly and wrong actually. Never provide struct page > >>pointers outside of the zone->lock. What I've had in mind was to simply > >>walk free lists of the suitable order and call the callback for each > >>one. > >>Something as simple as > >> > >> for (i = 0; i < MAX_NR_ZONES; i++) { > >> struct zone *zone = &pgdat->node_zones[i]; > >> > >> if (!populated_zone(zone)) > >> continue; > > > >Can we directly use for_each_populated_zone(zone) here? yes, my example couldn't because I was still assuming per-node API > >>spin_lock_irqsave(&zone->lock, flags); > >> for (order = min_order; order < MAX_ORDER; ++order) { > > > > > >This appears to be covered by for_each_migratetype_order(order, mt) below. yes but #define for_each_migratetype_order(order, type) \ for (order = 0; order < MAX_ORDER; order++) \ for (type = 0; type < MIGRATE_TYPES; type++) so you would have to skip orders < min_order -- Michal Hocko SUSE Labs