On Thu 05-05-16 00:30:35, Joonsoo Kim wrote: > 2016-05-04 18:21 GMT+09:00 Michal Hocko <mhocko@xxxxxxxxxx>: [...] > > Do we really consume 512B of stack during reclaim. That sounds more than > > worrying to me. > > Hmm...I checked it by ./script/stackusage and result is as below. > > shrink_zone() 128 > shrink_zone_memcg() 248 > shrink_active_list() 176 > > We have a call path that shrink_zone() -> shrink_zone_memcg() -> > shrink_active_list(). > I'm not sure whether it is the deepest path or not. This is definitely not the deepest path. Slab shrinkers can take more but 512B is still a lot. Some call paths are already too deep when calling into the allocator and some of them already use GFP_NOFS to prevent from potentially deep callchain slab shrinkers. Anyway worth exploring for better solutions. And I believe it would be better to solve this in the stackdepot directly so other users do not have to invent their own ways around the same issue. I have just checked the code and set_track uses save_stack which does the same thing and it seems to be called from the slab allocator. I have missed this usage before so the problem already does exist. It would be unfair to request you to fix that in order to add a new user. It would be great if this got addressed though. -- Michal Hocko SUSE Labs -- 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>