1 files changed, 260 insertions, 0 deletions
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
new file mode 100644
index 000000000000..4eb5ae3fbe10
--- /dev/null
+++ b/mm/hugetlb.c
@@ -0,0 +1,260 @@
+/*
+ * Generic hugetlb support.
+ * (C) William Irwin, April 2004
+ */
+#include <linux/gfp.h>
+#include <linux/list.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/mm.h>
+#include <linux/hugetlb.h>
+#include <linux/sysctl.h>
+#include <linux/highmem.h>
+#include <linux/nodemask.h>
+
+const unsigned long hugetlb_zero = 0, hugetlb_infinity = ~0UL;
+static unsigned long nr_huge_pages, free_huge_pages;
+unsigned long max_huge_pages;
+static struct list_head hugepage_freelists[MAX_NUMNODES];
+static unsigned int nr_huge_pages_node[MAX_NUMNODES];
+static unsigned int free_huge_pages_node[MAX_NUMNODES];
+static DEFINE_SPINLOCK(hugetlb_lock);
+
+static void enqueue_huge_page(struct page *page)
+{
+	int nid = page_to_nid(page);
+	list_add(&page->lru, &hugepage_freelists[nid]);
+	free_huge_pages++;
+	free_huge_pages_node[nid]++;
+}
+
+static struct page *dequeue_huge_page(void)
+{
+	int nid = numa_node_id();
+	struct page *page = NULL;
+
+	if (list_empty(&hugepage_freelists[nid])) {
+		for (nid = 0; nid < MAX_NUMNODES; ++nid)
+			if (!list_empty(&hugepage_freelists[nid]))
+				break;
+	}
+	if (nid >= 0 && nid < MAX_NUMNODES &&
+	    !list_empty(&hugepage_freelists[nid])) {
+		page = list_entry(hugepage_freelists[nid].next,
+				  struct page, lru);
+		list_del(&page->lru);
+		free_huge_pages--;
+		free_huge_pages_node[nid]--;
+	}
+	return page;
+}
+
+static struct page *alloc_fresh_huge_page(void)
+{
+	static int nid = 0;
+	struct page *page;
+	page = alloc_pages_node(nid, GFP_HIGHUSER|__GFP_COMP|__GFP_NOWARN,
+					HUGETLB_PAGE_ORDER);
+	nid = (nid + 1) % num_online_nodes();
+	if (page) {
+		nr_huge_pages++;
+		nr_huge_pages_node[page_to_nid(page)]++;
+	}
+	return page;
+}
+
+void free_huge_page(struct page *page)
+{
+	BUG_ON(page_count(page));
+
+	INIT_LIST_HEAD(&page->lru);
+	page[1].mapping = NULL;
+
+	spin_lock(&hugetlb_lock);
+	enqueue_huge_page(page);
+	spin_unlock(&hugetlb_lock);
+}
+
+struct page *alloc_huge_page(void)
+{
+	struct page *page;
+	int i;
+
+	spin_lock(&hugetlb_lock);
+	page = dequeue_huge_page();
+	if (!page) {
+		spin_unlock(&hugetlb_lock);
+		return NULL;
+	}
+	spin_unlock(&hugetlb_lock);
+	set_page_count(page, 1);
+	page[1].mapping = (void *)free_huge_page;
+	for (i = 0; i < (HPAGE_SIZE/PAGE_SIZE); ++i)
+		clear_highpage(&page[i]);
+	return page;
+}
+
+static int __init hugetlb_init(void)
+{
+	unsigned long i;
+	struct page *page;
+
+	for (i = 0; i < MAX_NUMNODES; ++i)
+		INIT_LIST_HEAD(&hugepage_freelists[i]);
+
+	for (i = 0; i < max_huge_pages; ++i) {
+		page = alloc_fresh_huge_page();
+		if (!page)
+			break;
+		spin_lock(&hugetlb_lock);
+		enqueue_huge_page(page);
+		spin_unlock(&hugetlb_lock);
+	}
+	max_huge_pages = free_huge_pages = nr_huge_pages = i;
+	printk("Total HugeTLB memory allocated, %ld\n", free_huge_pages);
+	return 0;
+}
+module_init(hugetlb_init);
+
+static int __init hugetlb_setup(char *s)
+{
+	if (sscanf(s, "%lu", &max_huge_pages) <= 0)
+		max_huge_pages = 0;
+	return 1;
+}
+__setup("hugepages=", hugetlb_setup);
+
+#ifdef CONFIG_SYSCTL
+static void update_and_free_page(struct page *page)
+{
+	int i;
+	nr_huge_pages--;
+	nr_huge_pages_node[page_zone(page)->zone_pgdat->node_id]--;
+	for (i = 0; i < (HPAGE_SIZE / PAGE_SIZE); i++) {
+		page[i].flags &= ~(1 << PG_locked | 1 << PG_error | 1 << PG_referenced |
+				1 << PG_dirty | 1 << PG_active | 1 << PG_reserved |
+				1 << PG_private | 1<< PG_writeback);
+		set_page_count(&page[i], 0);
+	}
+	set_page_count(page, 1);
+	__free_pages(page, HUGETLB_PAGE_ORDER);
+}
+
+#ifdef CONFIG_HIGHMEM
+static void try_to_free_low(unsigned long count)
+{
+	int i, nid;
+	for (i = 0; i < MAX_NUMNODES; ++i) {
+		struct page *page, *next;
+		list_for_each_entry_safe(page, next, &hugepage_freelists[i], lru) {
+			if (PageHighMem(page))
+				continue;
+			list_del(&page->lru);
+			update_and_free_page(page);
+			nid = page_zone(page)->zone_pgdat->node_id;
+			free_huge_pages--;
+			free_huge_pages_node[nid]--;
+			if (count >= nr_huge_pages)
+				return;
+		}
+	}
+}
+#else
+static inline void try_to_free_low(unsigned long count)
+{
+}
+#endif
+
+static unsigned long set_max_huge_pages(unsigned long count)
+{
+	while (count > nr_huge_pages) {
+		struct page *page = alloc_fresh_huge_page();
+		if (!page)
+			return nr_huge_pages;
+		spin_lock(&hugetlb_lock);
+		enqueue_huge_page(page);
+		spin_unlock(&hugetlb_lock);
+	}
+	if (count >= nr_huge_pages)
+		return nr_huge_pages;
+
+	spin_lock(&hugetlb_lock);
+	try_to_free_low(count);
+	while (count < nr_huge_pages) {
+		struct page *page = dequeue_huge_page();
+		if (!page)
+			break;
+		update_and_free_page(page);
+	}
+	spin_unlock(&hugetlb_lock);
+	return nr_huge_pages;
+}
+
+int hugetlb_sysctl_handler(struct ctl_table *table, int write,
+			   struct file *file, void __user *buffer,
+			   size_t *length, loff_t *ppos)
+{
+	proc_doulongvec_minmax(table, write, file, buffer, length, ppos);
+	max_huge_pages = set_max_huge_pages(max_huge_pages);
+	return 0;
+}
+#endif /* CONFIG_SYSCTL */
+
+int hugetlb_report_meminfo(char *buf)
+{
+	return sprintf(buf,
+			"HugePages_Total: %5lu\n"
+			"HugePages_Free:  %5lu\n"
+			"Hugepagesize:    %5lu kB\n",
+			nr_huge_pages,
+			free_huge_pages,
+			HPAGE_SIZE/1024);
+}
+
+int hugetlb_report_node_meminfo(int nid, char *buf)
+{
+	return sprintf(buf,
+		"Node %d HugePages_Total: %5u\n"
+		"Node %d HugePages_Free:  %5u\n",
+		nid, nr_huge_pages_node[nid],
+		nid, free_huge_pages_node[nid]);
+}
+
+int is_hugepage_mem_enough(size_t size)
+{
+	return (size + ~HPAGE_MASK)/HPAGE_SIZE <= free_huge_pages;
+}
+
+/* Return the number pages of memory we physically have, in PAGE_SIZE units. */
+unsigned long hugetlb_total_pages(void)
+{
+	return nr_huge_pages * (HPAGE_SIZE / PAGE_SIZE);
+}
+EXPORT_SYMBOL(hugetlb_total_pages);
+
+/*
+ * We cannot handle pagefaults against hugetlb pages at all.  They cause
+ * handle_mm_fault() to try to instantiate regular-sized pages in the
+ * hugegpage VMA.  do_page_fault() is supposed to trap this, so BUG is we get
+ * this far.
+ */
+static struct page *hugetlb_nopage(struct vm_area_struct *vma,
+				unsigned long address, int *unused)
+{
+	BUG();
+	return NULL;
+}
+
+struct vm_operations_struct hugetlb_vm_ops = {
+	.nopage = hugetlb_nopage,
+};
+
+void zap_hugepage_range(struct vm_area_struct *vma,
+			unsigned long start, unsigned long length)
+{
+	struct mm_struct *mm = vma->vm_mm;
+
+	spin_lock(&mm->page_table_lock);
+	unmap_hugepage_range(vma, start, start + length);
+	spin_unlock(&mm->page_table_lock);
+}