mm: meminit: initialise a subset of struct pages if CONFIG_DEFERRED_STRUCT_PAGE_INIT is set

This patch initalises all low memory struct pages and 2G of the highest
zone on each node during memory initialisation if
CONFIG_DEFERRED_STRUCT_PAGE_INIT is set.  That config option cannot be set
but will be available in a later patch.  Parallel initialisation of struct
page depends on some features from memory hotplug and it is necessary to
alter alter section annotations.

Signed-off-by: Mel Gorman <[email protected]>
Tested-by: Nate Zimmer <[email protected]>
Tested-by: Waiman Long <[email protected]>
Tested-by: Daniel J Blueman <[email protected]>
Acked-by: Pekka Enberg <[email protected]>
Cc: Robin Holt <[email protected]>
Cc: Nate Zimmer <[email protected]>
Cc: Dave Hansen <[email protected]>
Cc: Waiman Long <[email protected]>
Cc: Scott Norton <[email protected]>
Cc: "Luck, Tony" <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: "H. Peter Anvin" <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

1 files changed, 5 insertions, 1 deletions

diff --git a/drivers/base/node.c b/drivers/base/node.c
index a2aa65b4215d..31df474d72f4 100644
--- a/drivers/base/node.c
+++ b/drivers/base/node.c
@@ -359,12 +359,16 @@ int unregister_cpu_under_node(unsigned int cpu, unsigned int nid)
 #ifdef CONFIG_MEMORY_HOTPLUG_SPARSE
 #define page_initialized(page)  (page->lru.next)
 
-static int get_nid_for_pfn(unsigned long pfn)
+static int __init_refok get_nid_for_pfn(unsigned long pfn)
 {
 	struct page *page;
 
 	if (!pfn_valid_within(pfn))
 		return -1;
+#ifdef CONFIG_DEFERRED_STRUCT_PAGE_INIT
+	if (system_state == SYSTEM_BOOTING)
+		return early_pfn_to_nid(pfn);
+#endif
 	page = pfn_to_page(pfn);
 	if (!page_initialized(page))
 		return -1;