The following patch removes the individual free area initialization from
free_area_init_core(), and puts it in a new function
zone_init_free_lists().  It also creates pages_to_bitmap_size(), which
is then used in zone_init_free_lists() as well as several times in my
free area bitmap resizing patch.  

First of all, I think it looks nicer this way, but it's also necessary
to have this if you want to initialize a zone after system boot, like if
a NUMA node was hot-added.  In any case, it should be functionally
equivalent to the old code.

Compiles and boots on x86.  I've been running with this for a few weeks,
and haven't seen any problems with it yet.

 page_alloc.c |   86 ++++++++++++++++++++++++++++++++---------------------------
 1 files changed, 48 insertions(+), 38 deletions(-)

-- Dave