On Fri, 2005-03-11 at 19:25 +0000, Hugh Dickins wrote:
> This used to work fine, but around the time your abstract discontigmem
> patches went into -mm, the resulting kernel failed to boot - blank
> screen after grub for a few seconds, until it reboots again.  And now
> your patches have just gone into mainline, that resulting kernel fails
> to boot.  I've not done a binary search to identify any one of your
> patches as the culprit, but you are my Number One suspect ;)

Hugh, you caught me.  There is, indeed, a bug booting with
CONFIG_NUMA=y, CONFIG_X86_GENERICARCH=y, and booting on a non-NUMA
system.  While not the most common configuration, it should surely be
supported.

memmap_init_zone() is the first user to do pfn_to_nid(), which relies on
physnode_map[] to be done properly.  memory_present() was supposed to do
that, but never got called for the flat configuration, so pfn_to_nid()
was returning -1 on valid pages.

Andrew, please apply and forward the attached patch on to Linus.  It
affects code currently in -bk.

Test compiled and booted on 4-way non-NUMA x86 system.

-- Dave