Merge branch 'slab/next' of git://git.kernel.org/pub/scm/linux/kernel/git/penberg...

[platform/adaptation/renesas_rcar/renesas_kernel.git] / mm / memory_hotplug.c

diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index 1b6fe8c..489f235 100644 (file)
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -31,6 +31,7 @@
 #include <linux/firmware-map.h>
 #include <linux/stop_machine.h>
 #include <linux/hugetlb.h>
+#include <linux/memblock.h>
 
 #include <asm/tlbflush.h>
 
@@ -1422,6 +1423,36 @@ static bool can_offline_normal(struct zone *zone, unsigned long nr_pages)
 }
 #endif /* CONFIG_MOVABLE_NODE */
 
+static int __init cmdline_parse_movable_node(char *p)
+{
+#ifdef CONFIG_MOVABLE_NODE
+       /*
+        * Memory used by the kernel cannot be hot-removed because Linux
+        * cannot migrate the kernel pages. When memory hotplug is
+        * enabled, we should prevent memblock from allocating memory
+        * for the kernel.
+        *
+        * ACPI SRAT records all hotpluggable memory ranges. But before
+        * SRAT is parsed, we don't know about it.
+        *
+        * The kernel image is loaded into memory at very early time. We
+        * cannot prevent this anyway. So on NUMA system, we set any
+        * node the kernel resides in as un-hotpluggable.
+        *
+        * Since on modern servers, one node could have double-digit
+        * gigabytes memory, we can assume the memory around the kernel
+        * image is also un-hotpluggable. So before SRAT is parsed, just
+        * allocate memory near the kernel image to try the best to keep
+        * the kernel away from hotpluggable memory.
+        */
+       memblock_set_bottom_up(true);
+#else
+       pr_warn("movable_node option not supported\n");
+#endif
+       return 0;
+}
+early_param("movable_node", cmdline_parse_movable_node);
+
 /* check which state of node_states will be changed when offline memory */
 static void node_states_check_changes_offline(unsigned long nr_pages,
                struct zone *zone, struct memory_notify *arg)