mm: remove CONFIG_HAVE_MEMBLOCK_NODE_MAP option

CONFIG_HAVE_MEMBLOCK_NODE_MAP is used to differentiate initialization of
nodes and zones structures between the systems that have region to node
mapping in memblock and those that don't.

Currently all the NUMA architectures enable this option and for the
non-NUMA systems we can presume that all the memory belongs to node 0 and
therefore the compile time configuration option is not required.

The remaining few architectures that use DISCONTIGMEM without NUMA are
easily updated to use memblock_add_node() instead of memblock_add() and
thus have proper correspondence of memblock regions to NUMA nodes.

Still, free_area_init_node() must have a backward compatible version
because its semantics with and without CONFIG_HAVE_MEMBLOCK_NODE_MAP is
different.  Once all the architectures will use the new semantics, the
entire compatibility layer can be dropped.

To avoid addition of extra run time memory to store node id for
architectures that keep memblock but have only a single node, the node id
field of the memblock_region is guarded by CONFIG_NEED_MULTIPLE_NODES and
the corresponding accessors presume that in those cases it is always 0.

Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Tested-by: Hoan Tran <hoan@os.amperecomputing.com>	[arm64]
Acked-by: Catalin Marinas <catalin.marinas@arm.com>	[arm64]
Cc: Baoquan He <bhe@redhat.com>
Cc: Brian Cain <bcain@codeaurora.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Greentime Hu <green.hu@gmail.com>
Cc: Greg Ungerer <gerg@linux-m68k.org>
Cc: Guan Xuetao <gxt@pku.edu.cn>
Cc: Guo Ren <guoren@kernel.org>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Helge Deller <deller@gmx.de>
Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Ley Foon Tan <ley.foon.tan@intel.com>
Cc: Mark Salter <msalter@redhat.com>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Nick Hu <nickhu@andestech.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: Rich Felker <dalias@libc.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Stafford Horne <shorne@gmail.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Link: http://lkml.kernel.org/r/20200412194859.12663-4-rppt@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 2 insertions, 10 deletions

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 4288e6993dc8..5f15d8723167 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -2401,9 +2401,8 @@ static inline unsigned long get_num_physpages(void)
 	return phys_pages;
 }
 
-#ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP
 /*
- * With CONFIG_HAVE_MEMBLOCK_NODE_MAP set, an architecture may initialise its
+ * Using memblock node mappings, an architecture may initialise its
  * zones, allocate the backing mem_map and account for memory holes in a more
  * architecture independent manner. This is a substitute for creating the
  * zone_sizes[] and zholes_size[] arrays and passing them to
@@ -2424,9 +2423,6 @@ static inline unsigned long get_num_physpages(void)
  * registered physical page range.  Similarly
  * sparse_memory_present_with_active_regions() calls memory_present() for
  * each range when SPARSEMEM is enabled.
- *
- * See mm/page_alloc.c for more information on each function exposed by
- * CONFIG_HAVE_MEMBLOCK_NODE_MAP.
  */
 extern void free_area_init_nodes(unsigned long *max_zone_pfn);
 unsigned long node_map_pfn_alignment(void);
@@ -2441,13 +2437,9 @@ extern void free_bootmem_with_active_regions(int nid,
 						unsigned long max_low_pfn);
 extern void sparse_memory_present_with_active_regions(int nid);
 
-#endif /* CONFIG_HAVE_MEMBLOCK_NODE_MAP */
-
-#if !defined(CONFIG_HAVE_MEMBLOCK_NODE_MAP) && \
-    !defined(CONFIG_HAVE_ARCH_EARLY_PFN_TO_NID)
+#ifndef CONFIG_NEED_MULTIPLE_NODES
 static inline int early_pfn_to_nid(unsigned long pfn)
 {
-	BUILD_BUG_ON(IS_ENABLED(CONFIG_NUMA));
 	return 0;
 }
 #else