[PATCH 1/3] mem-hotplug: introduce movablenode option

[Xishi Qiu]

This patch introduces a new boot option movablenode.

To support memory hotplug, boot option "movable_node" is needed. And to
support debug memory hotplug, boot option "movable_node" and "movablenode"
are both needed.

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

It means node 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, so this boot option is used for debug.

Signed-off-by: Xishi Qiu <qiuxishi@xxxxxxxxxx>
---
 Documentation/kernel-parameters.txt |  4 ++++
 arch/x86/mm/srat.c                  | 36 ++++++++++++++++++++++++++++++++++++
 2 files changed, 40 insertions(+)

diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 82b42c9..f8726f8 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -2319,6 +2319,10 @@ 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.
 
+	movablenode=	[KNL,X86] Boot-time switch to set which node is
+			movable node.
+			Format: <movable nid>,...,<movable nid>
+
 	MTD_Partition=	[MTD]
 			Format: <name>,<region-number>,<size>,<offset>
 
diff --git a/arch/x86/mm/srat.c b/arch/x86/mm/srat.c
index b5f8218..c4cd81a 100644
--- a/arch/x86/mm/srat.c
+++ b/arch/x86/mm/srat.c
@@ -157,6 +157,38 @@ static inline int save_add_info(void) {return 1;}
 static inline int save_add_info(void) {return 0;}
 #endif
 
+static nodemask_t movablenode_mask;
+
+static void __init parse_movablenode_one(char *p)
+{
+	int node;
+
+	get_option(&p, &node);
+	node_set(node, movablenode_mask);
+}
+
+/*
+ * movablenode=<movable nid>,...,<movable nid> sets which node is movable
+ * node.
+ */
+static int __init parse_movablenode_opt(char *str)
+{
+#ifdef CONFIG_MOVABLE_NODE
+	while (str) {
+		char *k = strchr(str, ',');
+
+		if (k)
+			*k++ = 0;
+		parse_movablenode_one(str);
+		str = k;
+	}
+#else
+	pr_warn("movable_node option not supported\n");
+#endif
+	return 0;
+}
+early_param("movablenode", parse_movablenode_opt);
+
 /* Callback for parsing of the Proximity Domain <-> Memory Area mappings */
 int __init
 acpi_numa_memory_affinity_init(struct acpi_srat_mem_affinity *ma)
@@ -205,6 +237,10 @@ acpi_numa_memory_affinity_init(struct acpi_srat_mem_affinity *ma)
 
 	max_possible_pfn = max(max_possible_pfn, PFN_UP(end - 1));
 
+	if (node_isset(node, movablenode_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();
-- 
1.8.3.1