On Wed, Dec 10, 2014 at 09:38:42PM +0800, Weijie Yang wrote: > On Tue, Dec 9, 2014 at 5:59 PM, Mel Gorman <mgor...@suse.de> wrote: > > On Tue, Dec 09, 2014 at 03:40:35PM +0800, Weijie Yang wrote: > >> If the free page and its buddy has different zone id, the current > >> zone->lock cann't prevent buddy page getting allocated, this could > >> trigger VM_BUG_ON_PAGE in a very tiny chance: > >> > > > > Under what circumstances can a buddy page be allocated without the > > zone->lock? Any parallel allocation from that zone that takes place will > > be from the per-cpu allocator and should not be affected by this. Have > > you actually hit this race? > > My description maybe not clear, if the free page and its buddy is not > at the same zone, the holding zone->lock cann't prevent buddy page > getting allocated.
You're right, the description is not clear but now I see your point. Thanks. Acked-by: Mel Gorman <mgor...@suse.de> -- Mel Gorman SUSE Labs -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
