+
+#ifdef CONFIG_CMA
+static unsigned long hugetlb_cma_size __initdata;
+static bool cma_reserve_called __initdata;
+
+static int __init cmdline_parse_hugetlb_cma(char *p)
+{
+ hugetlb_cma_size = memparse(p, &p);
+ return 0;
+}
+
+early_param("hugetlb_cma", cmdline_parse_hugetlb_cma);
+
+void __init hugetlb_cma_reserve(int order)
+{
+ unsigned long size, reserved, per_node;
+ int nid;
+
+ cma_reserve_called = true;
+
+ if (!hugetlb_cma_size)
+ return;
+
+ if (hugetlb_cma_size < (PAGE_SIZE << order)) {
+ pr_warn("hugetlb_cma: cma area should be at least %lu MiB\n",
+ (PAGE_SIZE << order) / SZ_1M);
+ return;
+ }
+
+ /*
+ * If 3 GB area is requested on a machine with 4 numa nodes,
+ * let's allocate 1 GB on first three nodes and ignore the last one.
+ */
+ per_node = DIV_ROUND_UP(hugetlb_cma_size, nr_online_nodes);
+ pr_info("hugetlb_cma: reserve %lu MiB, up to %lu MiB per node\n",
+ hugetlb_cma_size / SZ_1M, per_node / SZ_1M);
+
+ reserved = 0;
+ for_each_node_state(nid, N_ONLINE) {
+ int res;
+
+ size = min(per_node, hugetlb_cma_size - reserved);
+ size = round_up(size, PAGE_SIZE << order);
+
+ res = cma_declare_contiguous_nid(0, size, 0, PAGE_SIZE << order,
+ 0, false, "hugetlb",
+ &hugetlb_cma[nid], nid);
+ if (res) {
+ pr_warn("hugetlb_cma: reservation failed: err %d, node %d",
+ res, nid);
+ continue;
+ }
+
+ reserved += size;
+ pr_info("hugetlb_cma: reserved %lu MiB on node %d\n",
+ size / SZ_1M, nid);
+
+ if (reserved >= hugetlb_cma_size)
+ break;
+ }
+}
+
+void __init hugetlb_cma_check(void)
+{
+ if (!hugetlb_cma_size || cma_reserve_called)
+ return;
+
+ pr_warn("hugetlb_cma: the option isn't supported by current arch\n");
+}
+
+#endif /* CONFIG_CMA */