On Tue 28-04-15 15:37:03, Mel Gorman wrote:
> early_pfn_in_nid() and meminit_pfn_in_nid() are small functions that are
> unnecessarily visible outside memory initialisation. As well as unnecessary
> visibility, it's unnecessary function call overhead when initialising pages.
> This patch moves the helpers inline.

This is causing:
  CC      mm/page_alloc.o
mm/page_alloc.c: In function a??deferred_init_memmapa??:
mm/page_alloc.c:1135:4: error: implicit declaration of function a??meminit_pfn_in_nida?? [-Werror=implicit-function-declaration]
    if (!meminit_pfn_in_nid(pfn, nid, &nid_init_state)) {
    ^

with randconfig test. CONFIG_NODES_SPAN_OTHER_NODES is not defined.
The full config is attached.

I guess we need something like this:

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 3e0257debce0..a48128d882d8 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -1044,6 +1044,11 @@ static inline bool __meminit early_pfn_in_nid(unsigned long pfn, int node)
 {
 	return true;
 }
+static inline bool __meminit meminit_pfn_in_nid(unsigned long pfn, int node,
+					struct mminit_pfnnid_cache *state)
+{
+	return true;
+}
 #endif
 
-- 
Michal Hocko
SUSE Labs