3 files changed, 37 insertions, 0 deletions

diff --git a/include/linux/memblock.h b/include/linux/memblock.h
index 97480d392e40..2f52c8c492bd 100644
--- a/include/linux/memblock.h
+++ b/include/linux/memblock.h
@@ -47,6 +47,10 @@ struct memblock {
 
 extern struct memblock memblock;
 extern int memblock_debug;
+#ifdef CONFIG_MOVABLE_NODE
+/* If movable_node boot option specified */
+extern bool movable_node_enabled;
+#endif /* CONFIG_MOVABLE_NODE */
 
 #define memblock_dbg(fmt, ...) \
         if (memblock_debug) printk(KERN_INFO pr_fmt(fmt), ##__VA_ARGS__)
@@ -65,6 +69,26 @@ int memblock_reserve(phys_addr_t base, phys_addr_t size);
 void memblock_trim_memory(phys_addr_t align);
 int memblock_mark_hotplug(phys_addr_t base, phys_addr_t size);
 int memblock_clear_hotplug(phys_addr_t base, phys_addr_t size);
+#ifdef CONFIG_MOVABLE_NODE
+static inline bool memblock_is_hotpluggable(struct memblock_region *m)
+{
+        return m->flags & MEMBLOCK_HOTPLUG;
+}
+
+static inline bool movable_node_is_enabled(void)
+{
+        return movable_node_enabled;
+}
+#else
+static inline bool memblock_is_hotpluggable(struct memblock_region *m)
+{
+        return false;
+}
+static inline bool movable_node_is_enabled(void)
+{
+        return false;
+}
+#endif
 
 #ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP
 int memblock_search_pfn_nid(unsigned long pfn, unsigned long *start_pfn,
diff --git a/mm/memblock.c b/mm/memblock.c
index d5681008dce1..6a2a48a122a9 100644
--- a/mm/memblock.c
+++ b/mm/memblock.c
@@ -39,6 +39,9 @@ struct memblock memblock __initdata_memblock = {
 };
 
 int memblock_debug __initdata_memblock;
+#ifdef CONFIG_MOVABLE_NODE
+bool movable_node_enabled __initdata_memblock = false;
+#endif
 static int memblock_can_resize __initdata_memblock;
 static int memblock_memory_in_slab __initdata_memblock = 0;
 static int memblock_reserved_in_slab __initdata_memblock = 0;
@@ -820,6 +823,11 @@ void __init_memblock __next_free_mem_range(u64 *idx, int nid,
  * @out_nid: ptr to int for nid of the range, can be %NULL
  *
  * Reverse of __next_free_mem_range().
+ *
+ * Linux kernel cannot migrate pages used by itself. Memory hotplug users won't
+ * be able to hot-remove hotpluggable memory used by the kernel. So this
+ * function skip hotpluggable regions if needed when allocating memory for the
+ * kernel.
  */
 void __init_memblock __next_free_mem_range_rev(u64 *idx, int nid,
                                            phys_addr_t *out_start,
@@ -844,6 +852,10 @@ void __init_memblock __next_free_mem_range_rev(u64 *idx, int nid,
                 if (nid != MAX_NUMNODES && nid != memblock_get_region_node(m))
                         continue;
 
+                /* skip hotpluggable memory regions if needed */
+                if (movable_node_is_enabled() && memblock_is_hotpluggable(m))
+                        continue;
+
                 /* scan areas before each reservation for intersection */
                 for ( ; ri >= 0; ri--) {
                         struct memblock_region *r = &rsv->regions[ri];
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index 489f235502db..01e39afde1cb 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -1446,6 +1446,7 @@ static int __init cmdline_parse_movable_node(char *p)
          * the kernel away from hotpluggable memory.
          */
         memblock_set_bottom_up(true);
+        movable_node_enabled = true;
 #else
         pr_warn("movable_node option not supported\n");
 #endif