[PATCH] hugetlb pages

Rohit Seth's ia32 huge tlb pages patch.

Anton Blanchard took a look at this today; he seemed happy
with it and said he could borrow bits.

arch/i386/Config.help

@@ -25,6 +25,15 @@ CONFIG_SMP
 
   If you don't know what to do here, say N.
 
+CONFIG_HUGETLB_PAGE
+  This enables support for huge pages.  User space applications
+  can make use of this support with the sys_alloc_hugepages and
+  sys_free_hugepages system calls.  If your applications are
+  huge page aware and your processor (Pentium or later for x86)
+  supports this, then say Y here.
+
+  Otherwise, say N.
+
 CONFIG_PREEMPT
   This option reduces the latency of the kernel when reacting to
   real-time or interactive events by allowing a low priority process to

arch/i386/config.in

@@ -154,6 +154,8 @@ if [ "$CONFIG_MWINCHIP3D" = "y" ]; then
    define_bool CONFIG_X86_OOSTORE y
 fi
 
+bool 'IA-32 Huge TLB Page Support (if available on processor)' CONFIG_HUGETLB_PAGE
+
 bool 'Symmetric multi-processing support' CONFIG_SMP
 bool 'Preemptible Kernel' CONFIG_PREEMPT
 if [ "$CONFIG_SMP" != "y" ]; then

arch/i386/kernel/entry.S

@@ -759,8 +759,8 @@ ENTRY(sys_call_table)
 	.long sys_io_getevents
 	.long sys_io_submit
 	.long sys_io_cancel
-	.long sys_ni_syscall	/* 250 */	/* sys_alloc_hugepages */
-	.long sys_ni_syscall			/* sys_free_hugepages */
+	.long sys_alloc_hugepages /* 250 */
+	.long sys_free_hugepages
 	.long sys_exit_group
 
 	.rept NR_syscalls-(.-sys_call_table)/4

arch/i386/kernel/sys_i386.c

@@ -246,3 +246,94 @@ asmlinkage int sys_olduname(struct oldold_utsname * name)
 
 	return error;
 }
+
+#ifdef CONFIG_HUGETLB_PAGE
+#define HPAGE_ALIGN(x)  (((unsigned long)x + (HPAGE_SIZE -1)) & HPAGE_MASK)
+extern long     sys_munmap(unsigned long, size_t);
+/* get_addr function gets the currently unused virtaul range in
+ * current process's address space.  It returns the LARGE_PAGE_SIZE
+ * aligned address (in cases of success).  Other kernel generic
+ * routines only could gurantee that allocated address is PAGE_SIZSE aligned.
+ */
+static unsigned long
+get_addr(unsigned long addr, unsigned long len)
+{
+	struct vm_area_struct   *vma;
+	if (addr) {
+		addr = HPAGE_ALIGN(addr);
+		vma = find_vma(current->mm, addr);
+		if (((TASK_SIZE - len) >= addr) &&
+				(!vma || addr + len <= vma->vm_start))
+			goto found_addr;
+	}
+	addr = HPAGE_ALIGN(TASK_UNMAPPED_BASE);
+	for (vma = find_vma(current->mm, addr); ; vma = vma->vm_next) {
+		if (TASK_SIZE - len < addr)
+			return -ENOMEM;
+		if (!vma || ((addr + len) < vma->vm_start))
+			goto found_addr;
+		addr = vma->vm_end;
+	}
+found_addr:
+	addr = HPAGE_ALIGN(addr);
+	return addr;
+}
+
+asmlinkage unsigned long
+sys_alloc_hugepages(int key, unsigned long addr, unsigned long len, int prot, int flag)
+{
+	struct mm_struct *mm = current->mm;
+	unsigned long   raddr;
+	int     retval = 0;
+	extern int alloc_hugetlb_pages(int, unsigned long, unsigned long, int, int);
+	if (!(cpu_has_pse))
+		return -EINVAL;
+	if (key < 0)
+		return -EINVAL;
+	if (len & (HPAGE_SIZE - 1))
+		return -EINVAL;
+	down_write(&mm->mmap_sem);
+	raddr = get_addr(addr, len);
+	if (raddr == -ENOMEM)
+		goto raddr_out;
+	retval = alloc_hugetlb_pages(key, raddr, len, prot, flag);
+
+raddr_out: up_write(&mm->mmap_sem);
+	if (retval < 0)
+		return (unsigned long) retval;
+	return raddr;
+}
+
+asmlinkage int
+sys_free_hugepages(unsigned long addr)
+{
+	struct mm_struct *mm = current->mm;
+	struct vm_area_struct   *vma;
+	int	retval;
+	extern int free_hugepages(struct vm_area_struct *);
+
+	vma = find_vma(current->mm, addr);
+	if ((!vma) || (!is_vm_hugetlb_page(vma)) || (vma->vm_start!=addr))
+		return -EINVAL;
+	down_write(&mm->mmap_sem);
+	spin_lock(&mm->page_table_lock);
+	retval =  free_hugepages(vma);
+	spin_unlock(&mm->page_table_lock);
+	up_write(&mm->mmap_sem);
+	return retval;
+}
+
+#else
+
+asmlinkage unsigned long
+sys_alloc_hugepages(int key, unsigned long addr, size_t len, int prot, int flag)
+{
+	return -ENOSYS;
+}
+asmlinkage int
+sys_free_hugepages(unsigned long addr)
+{
+	return -ENOSYS;
+}
+
+#endif

arch/i386/mm/Makefile

@@ -12,5 +12,6 @@ O_TARGET := mm.o
 obj-y	 := init.o pgtable.o fault.o ioremap.o extable.o pageattr.o 
 obj-$(CONFIG_DISCONTIGMEM)	+= discontig.o
 export-objs := pageattr.o
+obj-$(CONFIG_HUGETLB_PAGE) += hugetlbpage.o
 
 include $(TOPDIR)/Rules.make

arch/i386/mm/hugetlbpage.c

+/*
+ * IA-32 Huge TLB Page Support for Kernel.
+ *
+ * Copyright (C) 2002, Rohit Seth <rohit.seth@intel.com>
+ */
+
+#include <linux/config.h>
+#include <linux/init.h>
+#include <linux/fs.h>
+#include <linux/mm.h>
+#include <linux/pagemap.h>
+#include <linux/smp_lock.h>
+#include <linux/slab.h>
+
+#include <asm/mman.h>
+#include <asm/pgalloc.h>
+#include <asm/tlb.h>
+#include <asm/tlbflush.h>
+
+static struct vm_operations_struct hugetlb_vm_ops;
+struct list_head htlbpage_freelist;
+spinlock_t htlbpage_lock = SPIN_LOCK_UNLOCKED;
+extern long htlbpagemem;
+
+void zap_hugetlb_resources(struct vm_area_struct *);
+
+#define MAX_ID 	32
+struct htlbpagekey {
+	struct inode *in;
+	int key;
+} htlbpagek[MAX_ID];
+
+static struct inode *
+find_key_inode(int key)
+{
+	int i;
+
+	for (i = 0; i < MAX_ID; i++) {
+		if (htlbpagek[i].key == key)
+			return (htlbpagek[i].in);
+	}
+	return NULL;
+}
+static struct page *
+alloc_hugetlb_page(void)
+{
+	struct list_head *curr, *head;
+	struct page *page;
+
+	spin_lock(&htlbpage_lock);
+
+	head = &htlbpage_freelist;
+	curr = head->next;
+
+	if (curr == head) {
+		spin_unlock(&htlbpage_lock);
+		return NULL;
+	}
+	page = list_entry(curr, struct page, list);
+	list_del(curr);
+	htlbpagemem--;
+	spin_unlock(&htlbpage_lock);
+	set_page_count(page, 1);
+	memset(page_address(page), 0, HPAGE_SIZE);
+	return page;
+}
+
+static void
+free_hugetlb_page(struct page *page)
+{
+	spin_lock(&htlbpage_lock);
+	if ((page->mapping != NULL) && (page_count(page) == 2)) {
+		struct inode *inode = page->mapping->host;
+		int i;
+
+		ClearPageDirty(page);
+		remove_from_page_cache(page);
+		set_page_count(page, 1);
+		if ((inode->i_size -= HPAGE_SIZE) == 0) {
+			for (i = 0; i < MAX_ID; i++)
+				if (htlbpagek[i].key == inode->i_ino) {
+					htlbpagek[i].key = 0;
+					htlbpagek[i].in = NULL;
+					break;
+				}
+			kfree(inode);
+		}
+	}
+	if (put_page_testzero(page)) {
+		list_add(&page->list, &htlbpage_freelist);
+		htlbpagemem++;
+	}
+	spin_unlock(&htlbpage_lock);
+}
+
+static pte_t *
+huge_pte_alloc(struct mm_struct *mm, unsigned long addr)
+{
+	pgd_t *pgd;
+	pmd_t *pmd = NULL;
+
+	pgd = pgd_offset(mm, addr);
+	pmd = pmd_alloc(mm, pgd, addr);
+	return (pte_t *) pmd;
+}
+
+static pte_t *
+huge_pte_offset(struct mm_struct *mm, unsigned long addr)
+{
+	pgd_t *pgd;
+	pmd_t *pmd = NULL;
+
+	pgd = pgd_offset(mm, addr);
+	pmd = pmd_offset(pgd, addr);
+	return (pte_t *) pmd;
+}
+
+#define mk_pte_huge(entry) {entry.pte_low |= (_PAGE_PRESENT | _PAGE_PSE);}
+
+static void
+set_huge_pte(struct mm_struct *mm, struct vm_area_struct *vma,
+	     struct page *page, pte_t * page_table, int write_access)
+{
+	pte_t entry;
+
+	mm->rss += (HPAGE_SIZE / PAGE_SIZE);
+	if (write_access) {
+		entry =
+		    pte_mkwrite(pte_mkdirty(mk_pte(page, vma->vm_page_prot)));
+	} else
+		entry = pte_wrprotect(mk_pte(page, vma->vm_page_prot));
+	entry = pte_mkyoung(entry);
+	mk_pte_huge(entry);
+	set_pte(page_table, entry);
+	return;
+}
+
+static int
+anon_get_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma,
+	       int write_access, pte_t * page_table)
+{
+	struct page *page;
+
+	page = alloc_hugetlb_page();
+	if (page == NULL)
+		return -1;
+	set_huge_pte(mm, vma, page, page_table, write_access);
+	return 1;
+}
+
+int
+make_hugetlb_pages_present(unsigned long addr, unsigned long end, int flags)
+{
+	int write;
+	struct mm_struct *mm = current->mm;
+	struct vm_area_struct *vma;
+	pte_t *pte;
+
+	vma = find_vma(mm, addr);
+	if (!vma)
+		goto out_error1;
+
+	write = (vma->vm_flags & VM_WRITE) != 0;
+	if ((vma->vm_end - vma->vm_start) & (HPAGE_SIZE - 1))
+		goto out_error1;
+	spin_lock(&mm->page_table_lock);
+	do {
+		pte = huge_pte_alloc(mm, addr);
+		if ((pte) && (pte_none(*pte))) {
+			if (anon_get_hugetlb_page(mm, vma,
+					   write ? VM_WRITE : VM_READ,
+					   pte) == -1)
+				goto out_error;
+		} else
+			goto out_error;
+		addr += HPAGE_SIZE;
+	} while (addr < end);
+	spin_unlock(&mm->page_table_lock);
+	vma->vm_flags |= (VM_HUGETLB | VM_RESERVED);
+	if (flags & MAP_PRIVATE)
+		vma->vm_flags |= VM_DONTCOPY;
+	vma->vm_ops = &hugetlb_vm_ops;
+	return 0;
+out_error:		/* Error case, remove the partial lp_resources. */
+	if (addr > vma->vm_start) {
+		vma->vm_end = addr;
+		zap_hugetlb_resources(vma);
+		vma->vm_end = end;
+	}
+	spin_unlock(&mm->page_table_lock);
+      out_error1:
+	return -1;
+}
+
+int
+copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src,
+			struct vm_area_struct *vma)
+{
+	pte_t *src_pte, *dst_pte, entry;
+	struct page *ptepage;
+	unsigned long addr = vma->vm_start;
+	unsigned long end = vma->vm_end;
+
+	while (addr < end) {
+		dst_pte = huge_pte_alloc(dst, addr);
+		if (!dst_pte)
+			goto nomem;
+		src_pte = huge_pte_offset(src, addr);
+		entry = *src_pte;
+		ptepage = pte_page(entry);
+		get_page(ptepage);
+		set_pte(dst_pte, entry);
+		dst->rss += (HPAGE_SIZE / PAGE_SIZE);
+		addr += HPAGE_SIZE;
+	}
+	return 0;
+
+nomem:
+	return -ENOMEM;
+}
+
+int
+follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma,
+		    struct page **pages, struct vm_area_struct **vmas,
+		    unsigned long *st, int *length, int i)
+{
+	pte_t *ptep, pte;
+	unsigned long start = *st;
+	unsigned long pstart;
+	int len = *length;
+	struct page *page;
+
+	do {
+		pstart = start;
+		ptep = huge_pte_offset(mm, start);
+		pte = *ptep;
+
+back1:
+		page = pte_page(pte);
+		if (pages) {
+			page += ((start & ~HPAGE_MASK) >> PAGE_SHIFT);
+			pages[i] = page;
+		}
+		if (vmas)
+			vmas[i] = vma;
+		i++;
+		len--;
+		start += PAGE_SIZE;
+		if (((start & HPAGE_MASK) == pstart) && len &&
+				(start < vma->vm_end))
+			goto back1;
+	} while (len && start < vma->vm_end);
+	*length = len;
+	*st = start;
+	return i;
+}
+
+void
+zap_hugetlb_resources(struct vm_area_struct *mpnt)
+{
+	struct mm_struct *mm = mpnt->vm_mm;
+	unsigned long len, addr, end;
+	pte_t *ptep;
+	struct page *page;
+
+	addr = mpnt->vm_start;
+	end = mpnt->vm_end;
+	len = end - addr;
+	do {
+		ptep = huge_pte_offset(mm, addr);
+		page = pte_page(*ptep);
+		pte_clear(ptep);
+		free_hugetlb_page(page);
+		addr += HPAGE_SIZE;
+	} while (addr < end);
+	mm->rss -= (len >> PAGE_SHIFT);
+	mpnt->vm_ops = NULL;
+	flush_tlb_range(mpnt, end - len, end);
+}
+
+static void
+unlink_vma(struct vm_area_struct *mpnt)
+{
+	struct mm_struct *mm = current->mm;
+	struct vm_area_struct *vma;
+
+	vma = mm->mmap;
+	if (vma == mpnt) {
+		mm->mmap = vma->vm_next;
+	} else {
+		while (vma->vm_next != mpnt) {
+			vma = vma->vm_next;
+		}
+		vma->vm_next = mpnt->vm_next;
+	}
+	rb_erase(&mpnt->vm_rb, &mm->mm_rb);
+	mm->mmap_cache = NULL;
+	mm->map_count--;
+}
+
+int
+free_hugepages(struct vm_area_struct *mpnt)
+{
+	unlink_vma(mpnt);
+	zap_hugetlb_resources(mpnt);
+	kmem_cache_free(vm_area_cachep, mpnt);
+	return 1;
+}
+
+static struct inode *
+set_new_inode(unsigned long len, int prot, int flag, int key)
+{
+	struct inode *inode;
+	int i;
+
+	for (i = 0; i < MAX_ID; i++) {
+		if (htlbpagek[i].key == 0)
+			break;
+	}
+	if (i == MAX_ID)
+		return NULL;
+	inode = kmalloc(sizeof (struct inode), GFP_KERNEL);
+	if (inode == NULL)
+		return NULL;
+
+	inode_init_once(inode);
+	atomic_inc(&inode->i_writecount);
+	inode->i_mapping = &inode->i_data;
+	inode->i_mapping->host = inode;
+	inode->i_ino = (unsigned long)key;
+
+	htlbpagek[i].key = key;
+	htlbpagek[i].in = inode;
+	inode->i_uid = current->fsuid;
+	inode->i_gid = current->fsgid;
+	inode->i_mode = prot;
+	inode->i_size = len;
+	return inode;
+}
+
+static int
+check_size_prot(struct inode *inode, unsigned long len, int prot, int flag)
+{
+	if (inode->i_uid != current->fsuid)
+		return -1;
+	if (inode->i_gid != current->fsgid)
+		return -1;
+	if (inode->i_size != len)
+		return -1;
+	return 0;
+}
+
+static int
+alloc_shared_hugetlb_pages(int key, unsigned long addr, unsigned long len,
+			   int prot, int flag)
+{
+	struct mm_struct *mm = current->mm;
+	struct vm_area_struct *vma;
+	struct inode *inode;
+	struct address_space *mapping;
+	struct page *page;
+	int idx;
+	int retval = -ENOMEM;
+	int newalloc = 0;
+
+try_again:
+	spin_lock(&htlbpage_lock);
+
+	inode = find_key_inode(key);
+	if (inode == NULL) {
+		if (!capable(CAP_SYS_ADMIN)) {
+			if (!in_group_p(0)) {
+				retval = -EPERM;
+				goto out_err;
+			}
+		}
+		if (!(flag & IPC_CREAT)) {
+			retval = -ENOENT;
+			goto out_err;
+		}
+		inode = set_new_inode(len, prot, flag, key);
+		if (inode == NULL)
+			goto out_err;
+		newalloc = 1;
+	} else {
+		if (check_size_prot(inode, len, prot, flag) < 0) {
+			retval = -EINVAL;
+			goto out_err;
+		}
+		else if (atomic_read(&inode->i_writecount)) {
+			spin_unlock(&htlbpage_lock);
+			goto try_again;
+		}
+	}
+	spin_unlock(&htlbpage_lock);
+	mapping = inode->i_mapping;
+
+	addr = do_mmap_pgoff(NULL, addr, len, (unsigned long) prot,
+			MAP_NORESERVE|MAP_FIXED|MAP_PRIVATE|MAP_ANONYMOUS, 0);
+	if (IS_ERR((void *) addr))
+		goto freeinode;
+
+	vma = find_vma(mm, addr);
+	if (!vma) {
+		retval = -EINVAL;
+		goto freeinode;
+	}
+
+	spin_lock(&mm->page_table_lock);
+	do {
+		pte_t *pte = huge_pte_alloc(mm, addr);
+		if ((pte) && (pte_none(*pte))) {
+			idx = (addr - vma->vm_start) >> HPAGE_SHIFT;
+			page = find_get_page(mapping, idx);
+			if (page == NULL) {
+				page = alloc_hugetlb_page();
+				if (page == NULL)
+					goto out;
+				add_to_page_cache(page, mapping, idx);
+			}
+			set_huge_pte(mm, vma, page, pte,
+				     (vma->vm_flags & VM_WRITE));
+		} else
+			goto out;
+		addr += HPAGE_SIZE;
+	} while (addr < vma->vm_end);
+	retval = 0;
+	vma->vm_flags |= (VM_HUGETLB | VM_RESERVED);
+	vma->vm_ops = &hugetlb_vm_ops;
+	spin_unlock(&mm->page_table_lock);
+	spin_lock(&htlbpage_lock);
+	atomic_set(&inode->i_writecount, 0);
+	spin_unlock(&htlbpage_lock);
+	return retval;
+out:
+	if (addr > vma->vm_start) {
+		unsigned long raddr;
+		raddr = vma->vm_end;
+		vma->vm_end = addr;
+		zap_hugetlb_resources(vma);
+		vma->vm_end = raddr;
+	}
+	spin_unlock(&mm->page_table_lock);
+	do_munmap(mm, vma->vm_start, len);
+	if (newalloc)
+		goto freeinode;
+	return retval;
+out_err: spin_unlock(&htlbpage_lock);
+freeinode:
+	 if (newalloc) {
+		 for(idx=0;idx<MAX_ID;idx++)
+			 if (htlbpagek[idx].key == inode->i_ino) {
+				 htlbpagek[idx].key = 0;
+				 htlbpagek[idx].in = NULL;
+				 break;
+			 }
+		 kfree(inode);
+	 }
+	 return retval;
+}
+
+static int
+alloc_private_hugetlb_pages(int key, unsigned long addr, unsigned long len,
+			    int prot, int flag)
+{
+	if (!capable(CAP_SYS_ADMIN)) {
+		if (!in_group_p(0))
+			return -EPERM;
+	}
+	addr = do_mmap_pgoff(NULL, addr, len, prot,
+			MAP_NORESERVE|MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, 0);
+	if (IS_ERR((void *) addr))
+		return -ENOMEM;
+	if (make_hugetlb_pages_present(addr, (addr + len), flag) < 0) {
+		do_munmap(current->mm, addr, len);
+		return -ENOMEM;
+	}
+	return 0;
+}
+
+int
+alloc_hugetlb_pages(int key, unsigned long addr, unsigned long len, int prot,
+		    int flag)
+{
+	if (key > 0)
+		return alloc_shared_hugetlb_pages(key, addr, len, prot, flag);
+	return alloc_private_hugetlb_pages(key, addr, len, prot, flag);
+}
+
+int
+set_hugetlb_mem_size(int count)
+{
+	int j, lcount;
+	struct page *page, *map;
+	extern long htlbzone_pages;
+	extern struct list_head htlbpage_freelist;
+
+	if (count < 0)
+		lcount = count;
+	else
+		lcount = count - htlbzone_pages;
+
+	if (lcount > 0) {	/* Increase the mem size. */
+		while (lcount--) {
+			page = alloc_pages(GFP_ATOMIC, HUGETLB_PAGE_ORDER);
+			if (page == NULL)
+				break;
+			map = page;
+			for (j = 0; j < (HPAGE_SIZE / PAGE_SIZE); j++) {
+				SetPageReserved(map);
+				map++;
+			}
+			spin_lock(&htlbpage_lock);
+			list_add(&page->list, &htlbpage_freelist);
+			htlbpagemem++;
+			htlbzone_pages++;
+			spin_unlock(&htlbpage_lock);
+		}
+		return (int) htlbzone_pages;
+	}
+	/* Shrink the memory size. */
+	while (lcount++) {
+		page = alloc_hugetlb_page();
+		if (page == NULL)
+			break;
+		spin_lock(&htlbpage_lock);
+		htlbzone_pages--;
+		spin_unlock(&htlbpage_lock);
+		map = page;
+		for (j = 0; j < (HPAGE_SIZE / PAGE_SIZE); j++) {
+			map->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, 0);
+			map++;
+		}
+		set_page_count(page, 1);
+		__free_pages(page, HUGETLB_PAGE_ORDER);
+	}
+	return (int) htlbzone_pages;
+}
+
+static struct vm_operations_struct hugetlb_vm_ops = {
+	.close	= zap_hugetlb_resources,
+};

arch/i386/mm/init.c

@@ -431,6 +431,13 @@ static void __init set_max_mapnr_init(void)
 extern void set_max_mapnr_init(void);
 #endif /* !CONFIG_DISCONTIGMEM */
 
+#ifdef CONFIG_HUGETLB_PAGE
+long    htlbpagemem = 0;
+int     htlbpage_max;
+long    htlbzone_pages;
+extern struct list_head htlbpage_freelist;
+#endif
+
 void __init mem_init(void)
 {
 	extern int ppro_with_ram_bug(void);
@@ -493,6 +500,30 @@ void __init mem_init(void)
 #ifndef CONFIG_SMP
 	zap_low_mappings();
 #endif
+#ifdef CONFIG_HUGETLB_PAGE
+	{
+		long	i, j;
+		struct	page	*page, *map;
+		/*For now reserve quarter for hugetlb_pages.*/
+		htlbzone_pages = (max_low_pfn >> ((HPAGE_SHIFT - PAGE_SHIFT) + 2)) ;
+		/*Will make this kernel command line. */
+		INIT_LIST_HEAD(&htlbpage_freelist);
+		for (i=0; i<htlbzone_pages; i++) {
+			page = alloc_pages(GFP_ATOMIC, HUGETLB_PAGE_ORDER);
+			if (page == NULL)
+				break;
+			map = page;
+			for (j=0; j<(HPAGE_SIZE/PAGE_SIZE); j++) {
+				SetPageReserved(map);
+				map++;
+			}
+			list_add(&page->list, &htlbpage_freelist);
+		}
+		printk("Total Huge_TLB_Page memory pages allocated %ld\n", i);
+		htlbzone_pages = htlbpagemem = i;
+		htlbpage_max = i;
+	}
+#endif
 }
 
 #if CONFIG_X86_PAE

fs/proc/array.c

@@ -487,7 +487,18 @@ int proc_pid_statm(struct task_struct *task, char * buffer)
 		while (vma) {
 			pgd_t *pgd = pgd_offset(mm, vma->vm_start);
 			int pages = 0, shared = 0, dirty = 0, total = 0;
-
+			if (is_vm_hugetlb_page(vma)) {
+				int num_pages = ((vma->vm_end - vma->vm_start)/PAGE_SIZE);
+
+				resident += num_pages;
+				if (!(vma->vm_flags & VM_DONTCOPY))
+					share += num_pages;
+				if (vma->vm_flags & VM_WRITE)
+					dt += num_pages;
+				drs += num_pages;
+				vma = vma->vm_next;
+				continue;
+			}
 			statm_pgd_range(pgd, vma->vm_start, vma->vm_end, &pages, &shared, &dirty, &total);
 			resident += pages;
 			share += shared;

fs/proc/proc_misc.c

@@ -206,6 +206,19 @@ static int meminfo_read_proc(char *page, char **start, off_t off,
 		non_flushes
 		);
 
+#ifdef CONFIG_HUGETLB_PAGE
+	{
+		extern unsigned long htlbpagemem, htlbzone_pages;
+		len += sprintf(page + len,
+				"HugePages:    %8lu\n"
+				"Available:    %8lu\n"
+				"Size:         %8lu kB\n",
+				htlbzone_pages,
+				htlbpagemem,
+				HPAGE_SIZE/1024);
+	}
+
+#endif
 	return proc_calc_metrics(page, start, off, count, eof, len);
 #undef K
 }

include/asm-i386/page.h

@@ -44,14 +44,22 @@ typedef struct { unsigned long pte_low, pte_high; } pte_t;
 typedef struct { unsigned long long pmd; } pmd_t;
 typedef struct { unsigned long long pgd; } pgd_t;
 #define pte_val(x)	((x).pte_low | ((unsigned long long)(x).pte_high << 32))
+#define HPAGE_SHIFT	21
 #else
 typedef struct { unsigned long pte_low; } pte_t;
 typedef struct { unsigned long pmd; } pmd_t;
 typedef struct { unsigned long pgd; } pgd_t;
 #define pte_val(x)	((x).pte_low)
+#define HPAGE_SHIFT	22
 #endif
 #define PTE_MASK	PAGE_MASK
 
+#ifdef CONFIG_HUGETLB_PAGE
+#define HPAGE_SIZE	((1UL) << HPAGE_SHIFT)
+#define HPAGE_MASK	(~(HPAGE_SIZE - 1))
+#define HUGETLB_PAGE_ORDER	(HPAGE_SHIFT - PAGE_SHIFT)
+#endif
+
 typedef struct { unsigned long pgprot; } pgprot_t;
 
 #define pmd_val(x)	((x).pmd)

include/linux/mm.h

@@ -104,6 +104,7 @@ struct vm_area_struct {
 #define VM_DONTEXPAND	0x00040000	/* Cannot expand with mremap() */
 #define VM_RESERVED	0x00080000	/* Don't unmap it from swap_out */
 #define VM_ACCOUNT	0x00100000	/* Is a VM accounted object */
+#define VM_HUGETLB	0x00400000	/* Huge TLB Page VM */
 
 #define VM_STACK_FLAGS	(0x00000100 | VM_DATA_DEFAULT_FLAGS | VM_ACCOUNT)
 
@@ -377,6 +378,20 @@ int get_user_pages(struct task_struct *tsk, struct mm_struct *mm, unsigned long
 int __set_page_dirty_buffers(struct page *page);
 int __set_page_dirty_nobuffers(struct page *page);
 
+#ifdef CONFIG_HUGETLB_PAGE
+#define is_vm_hugetlb_page(vma) (vma->vm_flags & VM_HUGETLB)
+extern int copy_hugetlb_page_range(struct mm_struct *, struct mm_struct *, struct vm_area_struct *);
+extern int follow_hugetlb_page(struct mm_struct *, struct vm_area_struct *, struct page **, struct vm_area_struct **, unsigned long *, int *, int);
+extern	int free_hugepages(struct vm_area_struct *);
+
+#else
+#define is_vm_hugetlb_page(vma) (0)
+#define follow_hugetlb_page(mm, vma, pages, vmas, start, len, i) (0)
+#define copy_hugetlb_page_range(dst, src, vma) (0)
+#define free_hugepages(mpnt)  do { } while(0)
+#endif
+
+
 /*
  * If the mapping doesn't provide a set_page_dirty a_op, then
  * just fall through and assume that it wants buffer_heads.

include/linux/mmzone.h

@@ -16,7 +16,7 @@
  */
 
 #ifndef CONFIG_FORCE_MAX_ZONEORDER
-#define MAX_ORDER 10
+#define MAX_ORDER 11
 #else
 #define MAX_ORDER CONFIG_FORCE_MAX_ZONEORDER
 #endif

include/linux/sysctl.h

@@ -128,6 +128,7 @@ enum
 	KERN_TAINTED=53,	/* int: various kernel tainted flags */
 	KERN_CADPID=54,		/* int: PID of the process to notify on CAD */
 	KERN_PIDMAX=55,		/* int: PID # limit */
+	KERN_HUGETLB_PAGE_NUM=56, /* int: Number of available Huge Pages */
 };
 
 

kernel/sysctl.c

@@ -98,6 +98,11 @@ int proc_dol2crvec(ctl_table *table, int write, struct file *filp,
 extern int acct_parm[];
 #endif
 
+#ifdef CONFIG_HUGETLB_PAGE
+extern	int htlbpage_max;
+extern	int	set_hugetlb_mem_size(int);
+#endif
+
 static int parse_table(int *, int, void *, size_t *, void *, size_t,
 		       ctl_table *, void **);
 static int proc_doutsstring(ctl_table *table, int write, struct file *filp,
@@ -258,6 +263,10 @@ static ctl_table kern_table[] = {
 #endif
 	{KERN_PIDMAX, "pid_max", &pid_max, sizeof (int),
 	 0600, NULL, &proc_dointvec},
+#ifdef CONFIG_HUGETLB_PAGE
+	 {KERN_HUGETLB_PAGE_NUM, "numhugepages", &htlbpage_max, sizeof(int), 0644, NULL, 
+	  &proc_dointvec},
+#endif
 	{0}
 };
 
@@ -897,6 +906,10 @@ static int do_proc_dointvec(ctl_table *table, int write, struct file *filp,
 				val = -val;
 			buffer += len;
 			left -= len;
+#ifdef CONFIG_HUGETLB_PAGE
+			if (i == &htlbpage_max)
+				val = set_hugetlb_mem_size(val);
+#endif
 			switch(op) {
 			case OP_SET:	*i = val; break;
 			case OP_AND:	*i &= val; break;

mm/memory.c

@@ -208,6 +208,9 @@ int copy_page_range(struct mm_struct *dst, struct mm_struct *src,
 	unsigned long end = vma->vm_end;
 	unsigned long cow = (vma->vm_flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE;
 
+	if (is_vm_hugetlb_page(vma))
+		return copy_hugetlb_page_range(dst, src, vma);
+
 	src_pgd = pgd_offset(src, address)-1;
 	dst_pgd = pgd_offset(dst, address)-1;
 
@@ -530,6 +533,11 @@ int get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
 				|| !(flags & vma->vm_flags))
 			return i ? : -EFAULT;
 
+		if (is_vm_hugetlb_page(vma)) {
+			i = follow_hugetlb_page(mm, vma, pages, vmas,
+						&start, &len, i);
+			continue;
+		}
 		spin_lock(&mm->page_table_lock);
 		do {
 			struct page *map;

mm/mmap.c

@@ -1031,10 +1031,14 @@ static struct vm_area_struct *touched_by_munmap(struct mm_struct *mm,
 	touched = NULL;
 	do {
 		struct vm_area_struct *next = mpnt->vm_next;
-		mpnt->vm_next = touched;
-		touched = mpnt;
-		mm->map_count--;
-		rb_erase(&mpnt->vm_rb, &mm->mm_rb);
+		if (!(is_vm_hugetlb_page(mpnt))) {
+			mpnt->vm_next = touched;
+			touched = mpnt;
+			rb_erase(&mpnt->vm_rb, &mm->mm_rb);
+			mm->map_count--;
+		}
+		else
+			free_hugepages(mpnt);
 		mpnt = next;
 	} while (mpnt && mpnt->vm_start < end);
 	*npp = mpnt;
@@ -1273,7 +1277,10 @@ void exit_mmap(struct mm_struct * mm)
 			vm_unacct_memory((end - start) >> PAGE_SHIFT);
 
 		mm->map_count--;
-		unmap_page_range(tlb, mpnt, start, end);
+		if (!(is_vm_hugetlb_page(mpnt)))
+			unmap_page_range(tlb, mpnt, start, end);
+		else
+			mpnt->vm_ops->close(mpnt);
 		mpnt = mpnt->vm_next;
 	}
 

mm/mprotect.c

@@ -321,6 +321,11 @@ asmlinkage long sys_mprotect(unsigned long start, size_t len, unsigned long prot
 
 		/* Here we know that  vma->vm_start <= nstart < vma->vm_end. */
 
+		if (is_vm_hugetlb_page(vma)) {
+			error = -EACCES;
+			goto out;
+		}
+
 		newflags = prot | (vma->vm_flags & ~(PROT_READ | PROT_WRITE | PROT_EXEC));
 		if ((newflags & ~(newflags >> 4)) & 0xf) {
 			error = -EACCES;

mm/mremap.c

@@ -311,6 +311,10 @@ unsigned long do_mremap(unsigned long addr,
 	vma = find_vma(current->mm, addr);
 	if (!vma || vma->vm_start > addr)
 		goto out;
+	if (is_vm_hugetlb_page(vma)) {
+		ret = -EINVAL;
+		goto out;
+	}
 	/* We can't remap across vm area boundaries */
 	if (old_len > vma->vm_end - addr)
 		goto out;