gethugepagesizes man page

gethugepagesizes — Get the system supported huge page sizes


#include <hugetlbfs.h>

int gethugepagesizes(long pagesizes[], int n_elem);


The gethugepagesizes() function returns either the number of system supported huge page sizes or the sizes  themselves. If pagesizes is NULL and n_elem is 0, then the number of huge pages the system supports is returned. Otherwise, pagesizes is filled with at most n_elem page sizes.

Return Value

On success, either the number of huge page sizes supported by the system or the number of huge page sizes stored in pagesizes is returned. On failure, -1 is returned and errno is set appropriately.



n_elem is less than zero or n_elem is greater than zero and pagesizes is NULL.

Also see opendir(3) for other possible values for errno. This error occurs when the sysfs directory exists but cannot be opened.


This call will return all huge page sizes as reported by the kernel. Not all of these sizes may be usable by the programmer since mount points may not be available for all sizes.  To test whether a size will be usable by libhugetlbfs, hugetlbfs_find_path_for_size() can be called on a specific size to see if a mount point is configured.

See Also

oprofile(1), opendir(3), hugetlbfs_find_path_for_size(3), libhugetlbfs(7)


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

Referenced By

getpagesizes(3), hugetlbfs_find_path(3), hugetlbfs_unlinked_fd(3), libhugetlbfs(7), pagesize(1).

October 10, 2008