GET_HUGE_PAGES(3)					     Library Functions Manual						 GET_HUGE_PAGES(3)

NAME

       get_huge_pages, free_huge_pages - Allocate and free hugepages

SYNOPSIS

       #include <hugetlbfs.h>

       void *get_huge_pages(size_t len, ghp_t flags);
       void free_huge_pages(void *ptr);

DESCRIPTION

       get_huge_pages()  allocates  a  memory  region  len bytes in size backed by hugepages. Hugepages may be of benefit to applications that use
       large amounts of address space and suffer a  performance hit  due to  TLB misses.  Wall-clock  time or oprofile can be used to determine if
       there is a performance benefit from using hugepages or not.

       The  len  parameter must be hugepage-aligned. In the current implementation, only the default hugepage size may be allocated via this func-
       tion. Use gethugepagesize to discover what the alignment should be.

       The flags argument changes the behaviour of the function. Flags may be or'd together.

       GHP_DEFAULT

	      Allocate a region of memory of the requested length backed by hugepages of the default hugepage  size.  Return  NULL  if	sufficient
	      pages are not available

       free_huge_pages()  frees  a region of memory allocated by get_huge_pages(). The behaviour of the function if another pointer is used, valid
       or otherwise, is undefined.

RETURN VALUE

       On success, a pointer is returned to the allocated memory. On error, NULL is returned. errno will be set  based	on  what  the  failure	of
       mmap() was due to.

SEE ALSO

       oprofile(1) , gethugepagesize(3) , get_hugepage_region(3) , libhugetlbfs(7)

AUTHORS

       libhugetlbfs was written by various people on the libhugetlbfs-devel mailing list.

								  October 8, 2008						 GET_HUGE_PAGES(3)