[RFC 27/43] x86/mm/numa: add numa_isolate_memblocks()

[Anthony Yznaga <anthony.yznaga@oracle.com>]

Provide a way for a caller external to numa to ensure memblocks in the
memblock reserved list do not cross node boundaries and have a node id
assigned to them.  This will be used by PKRAM to ensure initialization of
page structs for preserved pages can be deferred and multithreaded
efficiently.

Signed-off-by: Anthony Yznaga <anthony.yznaga@oracle.com>
---
 arch/x86/include/asm/numa.h |  4 ++++
 arch/x86/mm/numa.c          | 32 ++++++++++++++++++++------------
 2 files changed, 24 insertions(+), 12 deletions(-)

diff --git a/arch/x86/include/asm/numa.h b/arch/x86/include/asm/numa.h
index bbfde3d2662f..f9e05f4eb1c6 100644
--- a/arch/x86/include/asm/numa.h
+++ b/arch/x86/include/asm/numa.h
@@ -40,6 +40,7 @@ static inline void set_apicid_to_node(int apicid, s16 node)
 }
 
 extern int numa_cpu_node(int cpu);
+extern void __init numa_isolate_memblocks(void);
 
 #else	/* CONFIG_NUMA */
 static inline void set_apicid_to_node(int apicid, s16 node)
@@ -50,6 +51,9 @@ static inline int numa_cpu_node(int cpu)
 {
 	return NUMA_NO_NODE;
 }
+static inline void numa_isolate_memblocks(void)
+{
+}
 #endif	/* CONFIG_NUMA */
 
 #ifdef CONFIG_X86_32
diff --git a/arch/x86/mm/numa.c b/arch/x86/mm/numa.c
index 59ba008504dc..df0065e24ea5 100644
--- a/arch/x86/mm/numa.c
+++ b/arch/x86/mm/numa.c
@@ -475,6 +475,25 @@ static bool __init numa_meminfo_cover_memory(const struct numa_meminfo *mi)
 	return true;
 }
 
+void __init numa_isolate_memblocks(void)
+{
+	int i;
+
+	/*
+	 * Iterate over all memory known to the x86 architecture,
+	 * and use those ranges to set the nid in memblock.reserved.
+	 * This will split up the memblock regions along node
+	 * boundaries and will set the node IDs as well.
+	 */
+	for (i = 0; i < numa_meminfo.nr_blks; i++) {
+		struct numa_memblk *mb = numa_meminfo.blk + i;
+		int ret;
+
+		ret = memblock_set_node(mb->start, mb->end - mb->start, &memblock.reserved, mb->nid);
+		WARN_ON_ONCE(ret);
+	}
+}
+
 /*
  * Mark all currently memblock-reserved physical memory (which covers the
  * kernel's own memory ranges) as hot-unswappable.
@@ -493,19 +512,8 @@ static void __init numa_clear_kernel_node_hotplug(void)
 	 * used by the kernel, but those regions are not split up
 	 * along node boundaries yet, and don't necessarily have their
 	 * node ID set yet either.
-	 *
-	 * So iterate over all memory known to the x86 architecture,
-	 * and use those ranges to set the nid in memblock.reserved.
-	 * This will split up the memblock regions along node
-	 * boundaries and will set the node IDs as well.
 	 */
-	for (i = 0; i < numa_meminfo.nr_blks; i++) {
-		struct numa_memblk *mb = numa_meminfo.blk + i;
-		int ret;
-
-		ret = memblock_set_node(mb->start, mb->end - mb->start, &memblock.reserved, mb->nid);
-		WARN_ON_ONCE(ret);
-	}
+	numa_isolate_memblocks();
 
 	/*
 	 * Now go over all reserved memblock regions, to construct a
-- 
2.13.3