new file mode 100644
@@ -0,0 +1 @@
+obj-m += dmem-test.o
new file mode 100644
@@ -0,0 +1,10 @@
+KDIR ?= ../../../
+
+default:
+ $(MAKE) -C $(KDIR) M=$$PWD
+
+install: default
+ $(MAKE) -C $(KDIR) M=$$PWD modules_install
+
+clean:
+ rm -f *.o *.ko Module.* modules.* *.mod.c
new file mode 100644
@@ -0,0 +1,184 @@
+/*
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of version 2 of the GNU General Public License as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ */
+#include <linux/kernel.h>
+#include <linux/types.h>
+#include <linux/module.h>
+#include <linux/sizes.h>
+#include <linux/list.h>
+#include <linux/nodemask.h>
+#include <linux/slab.h>
+#include <linux/dmem.h>
+
+struct dmem_mem_node {
+ struct list_head node;
+};
+
+static LIST_HEAD(dmem_list);
+
+static int dmem_test_alloc_init(unsigned long dpage_shift)
+{
+ int ret;
+
+ ret = dmem_alloc_init(dpage_shift);
+ if (ret)
+ pr_info("dmem_alloc_init failed, dpage_shift %ld ret=%d\n",
+ dpage_shift, ret);
+ return ret;
+}
+
+static int __dmem_test_alloc(int order, int nid, nodemask_t *nodemask,
+ const char *caller)
+{
+ struct dmem_mem_node *pos;
+ phys_addr_t addr;
+ int i, ret = 0;
+
+ for (i = 0; i < (1 << order); i++) {
+ addr = dmem_alloc_pages_nodemask(nid, nodemask, 1, NULL);
+ if (!addr) {
+ ret = -ENOMEM;
+ break;
+ }
+
+ pos = __va(addr);
+ list_add(&pos->node, &dmem_list);
+ }
+
+ pr_info("%s: alloc order %d on node %d has fallback node %s... %s.\n",
+ caller, order, nid, nodemask ? "yes" : "no",
+ !ret ? "okay" : "failed");
+
+ return ret;
+}
+
+static void dmem_test_free_all(void)
+{
+ struct dmem_mem_node *pos, *n;
+
+ list_for_each_entry_safe(pos, n, &dmem_list, node) {
+ list_del(&pos->node);
+ dmem_free_page(__pa(pos));
+ }
+}
+
+#define dmem_test_alloc(order, nid, nodemask) \
+ __dmem_test_alloc(order, nid, nodemask, __func__)
+
+/* dmem shoud have 2^6 native pages available at lest */
+static int order_test(void)
+{
+ int order, i, ret;
+ int page_orders[] = {0, 1, 2, 3, 4, 5, 6};
+
+ ret = dmem_test_alloc_init(PAGE_SHIFT);
+ if (ret)
+ return ret;
+
+ for (i = 0; i < ARRAY_SIZE(page_orders); i++) {
+ order = page_orders[i];
+
+ ret = dmem_test_alloc(order, numa_node_id(), NULL);
+ if (ret)
+ break;
+ }
+
+ dmem_test_free_all();
+
+ dmem_alloc_uinit();
+
+ return ret;
+}
+
+static int node_test(void)
+{
+ nodemask_t nodemask;
+ unsigned long nr = 0;
+ int order;
+ int node;
+ int ret = 0;
+
+ order = 0;
+
+ ret = dmem_test_alloc_init(PUD_SHIFT);
+ if (ret)
+ return ret;
+
+ pr_info("%s: test allocation on node 0\n", __func__);
+ node = 0;
+ nodes_clear(nodemask);
+ node_set(0, nodemask);
+
+ ret = dmem_test_alloc(order, node, &nodemask);
+ if (ret)
+ goto exit;
+
+ dmem_test_free_all();
+
+ pr_info("%s: begin to exhaust dmem on node 0.\n", __func__);
+ node = 1;
+ nodes_clear(nodemask);
+ node_set(0, nodemask);
+
+ INIT_LIST_HEAD(&dmem_list);
+ while (!(ret = dmem_test_alloc(order, node, &nodemask)))
+ nr++;
+
+ pr_info("Allocation on node 0 success times: %lu\n", nr);
+
+ pr_info("%s: allocation on node 0 again\n", __func__);
+ node = 0;
+ nodes_clear(nodemask);
+ node_set(0, nodemask);
+ ret = dmem_test_alloc(order, node, &nodemask);
+ if (!ret) {
+ pr_info("\tNot expected fallback\n");
+ ret = -1;
+ } else {
+ ret = 0;
+ pr_info("\tOK, Dmem on node 0 exhausted, fallback success\n");
+ }
+
+ pr_info("%s: Release dmem\n", __func__);
+ dmem_test_free_all();
+
+exit:
+ dmem_alloc_uinit();
+ return ret;
+}
+
+static __init int dmem_test_init(void)
+{
+ int ret;
+
+ pr_info("dmem: test init...\n");
+
+ ret = order_test();
+ if (ret)
+ return ret;
+
+ ret = node_test();
+
+
+ if (ret)
+ pr_info("dmem test fail, ret=%d\n", ret);
+ else
+ pr_info("dmem test success\n");
+ return ret;
+}
+
+static __exit void dmem_test_exit(void)
+{
+ pr_info("dmem: test exit...\n");
+}
+
+module_init(dmem_test_init);
+module_exit(dmem_test_exit);
+MODULE_LICENSE("GPL v2");