mem-hotplug: introduce movablenodes boot option for memory hotplug debugging

This patch introduces a new boot option "movablenodes". This parameter depends on movable_node, it is used for debugging memory hotplug. Instead SRAT specifies which memory is hotpluggable.

e.g. movable_node movablenodes=1,2,4

It means nodes 1,2,4 will be set to movable nodes, the other nodes are unmovable nodes. Usually movable nodes are parsed from SRAT table which offered by BIOS.

Signed-off-by Xishi Qiu <[email protected]>

---
  Documentation/kernel-parameters.txt |    5 ++++
  arch/x86/mm/srat.c                  |   36 +++++++++++++++++++++++++++++++++++
  2 files changed, 41 insertions(+), 0 deletions(-)

Documentation/kernel-parameters.txt +5 -0

index 5ae8608..e072ccf 100644
@@ -1949,6 +1949,11 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
  	movable_node	[KNL,X86] Boot-time switch to enable the effects
  			of CONFIG_MOVABLE_NODE=y. See mm/Kconfig for details.
 
+	movablenodes=	[KNL,X86] This parameter depends on movable_node, it
+			is used for debugging memory hotplug. Instead SRAT
+			specifies which memory is hotpluggable.
+			e.g. movablenodes=1,2,4
+
  	MTD_Partition=	[MTD]
  			Format: <name>,<region-number>,<size>,<offset>
 

arch/x86/mm/srat.c +36 -0

index 66338a6..523e58b 100644
@@ -157,6 +157,37 @@ static inline int save_add_info(void) {return 1;}
  static inline int save_add_info(void) {return 0;}
  #endif
 
+static nodemask_t movablenodes_mask;
+
+static void __init parse_movablenodes_one(char *p)
+{
+	int node;
+
+	get_option(&p, &node);
+	node_set(node, movablenodes_mask);
+}
+
+static int __init parse_movablenodes_opt(char *str)
+{
+	nodes_clear(movablenodes_mask);
+
+#ifdef CONFIG_MOVABLE_NODE
+	while (str) {
+		char *k = strchr(str, ',');
+
+		if (k)
+			*k++ = 0;
+		parse_movablenodes_one(str);
+		str = k;
+	}
+#else
+	pr_warn("movable_node option not supported\n");
+#endif
+
+	return 0;
+}
+early_param("movablenodes", parse_movablenodes_opt);
+
  /* Callback for parsing of the Proximity Domain <-> Memory Area mappings */
  int __init
  acpi_numa_memory_affinity_init(struct acpi_srat_mem_affinity *ma)

@@ -202,6 +233,11 @@ acpi_numa_memory_affinity_init(struct acpi_srat_mem_affinity *ma)
  		pr_warn("SRAT: Failed to mark hotplug range [mem %#010Lx-%#010Lx] in memblock\n",
  			(unsigned long long)start, (unsigned long long)end - 1);
 
+	if (node_isset(node, movablenodes_mask) &&
+		memblock_mark_hotplug(start, ma->length))
+		pr_warn("SRAT debug: Failed to mark hotplug range [mem %#010Lx-%#010Lx] in memblock\n",
+			(unsigned long long)start, (unsigned long long)end - 1);
+
  	return 0;
  out_err_bad_srat:
  	bad_srat();