Messages in this thread | | | Subject | Re: assert/crash in __rmqueue() when enabling CONFIG_NUMA | From | Dave Hansen <> | Date | Fri, 05 May 2006 07:57:44 -0700 |
| |
On Fri, 2006-05-05 at 10:50 -0400, Bob Picco wrote: > Dave Hansen wrote: [Fri May 05 2006, 10:33:10AM EDT] > > The page_zonenum() checks look good, but I'm not sure I understand the > > page_in_zone_hole() part. If a page is in a hole in a zone, it will > > still have a valid mem_map entry, right? It should also never have been > > put into the allocator, so it also won't ever be coalesced. > This has always been subtle and not too revealing. It probably should > have a comment. The page_in_zone_hole check is for ia64 > VIRTUAL_MEM_MAP. You might compute a page structure which is in a hole not > backed by memory; an unallocated page which covers pages structures. > VIRTUAL_MEM_MAP uses a contiguous virtual region with virtual space holes > not backed by memory. Take a look at ia64_pfn_valid.
Ahhh. I hadn't made the ia64 connection. I wonder if it is worth making CONFIG_HOLES_IN_ZONE say ia64 or something about vmem_map in it somewhere. Might be worth at least a comment like this:
+ if (page_in_zone_hole(buddy)) /* noop on all but ia64 */ + break; + else if (page_zonenum(buddy) != page_zonenum(page)) + break; + else if (!page_is_buddy(buddy, order)) break; /* Move the buddy up one level. */
BTW, wasn't the whole idea of discontig to have holes in zones (before NUMA) without tricks like this? ;)
-- Dave
- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |