From: Wei Yang <richard.weiyang@xxxxxxxxx> Subject: lib/show_mem.c: drop pgdat_resize_lock in show_mem() Function show_mem() is used to print system memory status when user requires or fail to allocate memory. Generally, this is a best effort information so any races with memory hotplug (or very theoretically an early initialization) should be tolerable and the worst that could happen is to print an imprecise node state. Drop the resize lock because this is the only place which might hold the lock from the interrupt context and so all other callers might use a simple spinlock. Even though this doesn't solve any real issue it makes the code easier to follow and tiny more effective. Link: http://lkml.kernel.org/r/20181129235532.9328-1-richard.weiyang@xxxxxxxxx Signed-off-by: Wei Yang <richard.weiyang@xxxxxxxxx> Acked-by: Michal Hocko <mhocko@xxxxxxxx> Reviewed-by: Oscar Salvador <osalvador@xxxxxxx> Cc: Johannes Weiner <hannes@xxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- --- a/lib/show_mem.c~mm-show_mem-drop-pgdat_resize_lock-in-show_mem +++ a/lib/show_mem.c @@ -18,10 +18,8 @@ void show_mem(unsigned int filter, nodem show_free_areas(filter, nodemask); for_each_online_pgdat(pgdat) { - unsigned long flags; int zoneid; - pgdat_resize_lock(pgdat, &flags); for (zoneid = 0; zoneid < MAX_NR_ZONES; zoneid++) { struct zone *zone = &pgdat->node_zones[zoneid]; if (!populated_zone(zone)) @@ -33,7 +31,6 @@ void show_mem(unsigned int filter, nodem if (is_highmem_idx(zoneid)) highmem += zone->present_pages; } - pgdat_resize_unlock(pgdat, &flags); } printk("%lu pages RAM\n", total); _
