When I mmap anonymous hugepages with MAP_HUGETLB and there are available (pre-reserved) hugepages available, but only on the wrong node, things blow up. The mmap succeeds, as it should (the accounting here is wrong -- known issue AFAIK, but that's only relevant to MPOL_BIND or cpusets). But writing to the resulting page causes a SIGBUS.
AFAICS the issue is that dequeue_huge_page_vma is calling huge_zonelist, which returns a single-entry nodemask. The loop over allowable zones* will never try other numa zones, and the function fails. I'm not sure whether it would be better to try other nodes first or to try get get a page from the buddy allocator on the preferred node first, but currently the other nodes' reserved lists are never checked. The result is a crash. Working around this in userspace is going to be a real PITA. Grr. * Why is this iterating zones instead of nodes? --Andy -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
