[PATCH] x86_64: Handle empty PXMs that only contain hotplug memory

The node setup code would try to allocate the node metadata in the node
itself, but that fails if there is no memory in there.

This can happen with memory hotplug when the hotplug area defines an so
far empty node.

Now use bootmem to try to allocate the mem_map in other nodes.

And if it fails don't panic, but just ignore the node.

To make this work I added a new __alloc_bootmem_nopanic function that
does what its name implies.

TBD should try to use nearby nodes here.  Currently we just use any.
It's hard to do it better because bootmem doesn't have proper fallback
lists yet.

Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 8 insertions, 1 deletions

diff --git a/mm/bootmem.c b/mm/bootmem.c
index d3e3bd2ffcea..d213feded10d 100644
--- a/mm/bootmem.c
+++ b/mm/bootmem.c
@@ -401,7 +401,7 @@ unsigned long __init free_all_bootmem (void)
         return(free_all_bootmem_core(NODE_DATA(0)));
 }
 
-void * __init __alloc_bootmem(unsigned long size, unsigned long align, unsigned long goal)
+void * __init __alloc_bootmem_nopanic(unsigned long size, unsigned long align, unsigned long goal)
 {
         bootmem_data_t *bdata;
         void *ptr;
@@ -409,7 +409,14 @@ void * __init __alloc_bootmem(unsigned long size, unsigned long align, unsigned
         list_for_each_entry(bdata, &bdata_list, list)
                 if ((ptr = __alloc_bootmem_core(bdata, size, align, goal, 0)))
                         return(ptr);
+        return NULL;
+}
 
+void * __init __alloc_bootmem(unsigned long size, unsigned long align, unsigned long goal)
+{
+        void *mem = __alloc_bootmem_nopanic(size,align,goal);
+        if (mem)
+                return mem;
         /*
          * Whoops, we cannot satisfy the allocation request.
          */