svcadm(8)을 검색하려면 섹션에서 8 을 선택하고, 맨 페이지 이름에 svcadm을 입력하고 검색을 누른다.
free_hugepages(2)
ALLOC_HUGEPAGES(2) Linux Programmer's Manual ALLOC_HUGEPAGES(2)
NAME
alloc_hugepages, free_hugepages - allocate or free huge pages
SYNOPSIS
void *alloc_hugepages(int key, void *addr, size_t len,
int prot, int flag);
int free_hugepages(void *addr);
DESCRIPTION
The system calls alloc_hugepages() and free_hugepages() were introduced
in Linux 2.5.36 and removed again in 2.5.54. They existed only on i386
and ia64 (when built with CONFIG_HUGETLB_PAGE). In Linux 2.4.20, the
syscall numbers exist, but the calls fail with the error ENOSYS.
On i386 the memory management hardware knows about ordinary pages
(4 KiB) and huge pages (2 or 4 MiB). Similarly ia64 knows about huge
pages of several sizes. These system calls serve to map huge pages
into the process's memory or to free them again. Huge pages are locked
into memory, and are not swapped.
The key argument is an identifier. When zero the pages are private,
and not inherited by children. When positive the pages are shared with
other applications using the same key, and inherited by child
processes.
The addr argument of free_hugepages() tells which page is being freed:
it was the return value of a call to alloc_hugepages(). (The memory is
first actually freed when all users have released it.) The addr argu‐
ment of alloc_hugepages() is a hint, that the kernel may or may not
follow. Addresses must be properly aligned.
The len argument is the length of the required segment. It must be a
multiple of the huge page size.
The prot argument specifies the memory protection of the segment. It
is one of PROT_READ, PROT_WRITE, PROT_EXEC.
The flag argument is ignored, unless key is positive. In that case, if
flag is IPC_CREAT, then a new huge page segment is created when none
with the given key existed. If this flag is not set, then ENOENT is
returned when no segment with the given key exists.
RETURN VALUE
On success, alloc_hugepages() returns the allocated virtual address,
and free_hugepages() returns zero. On error, -1 is returned, and errno
is set appropriately.
ERRORS
ENOSYS The system call is not supported on this kernel.
FILES
/proc/sys/vm/nr_hugepages
Number of configured hugetlb pages. This can be read and writ‐
ten.
/proc/meminfo
Gives info on the number of configured hugetlb pages and on
their size in the three variables HugePages_Total,
HugePages_Free, Hugepagesize.
CONFORMING TO
These calls are specific to Linux on Intel processors, and should not
be used in programs intended to be portable.
NOTES
These system calls are gone; they existed only in Linux 2.5.36 through
to 2.5.54. Now the hugetlbfs filesystem can be used instead. Memory
backed by huge pages (if the CPU supports them) is obtained by using
mmap(2) to map files in this virtual filesystem.
The maximal number of huge pages can be specified using the hugepages=
boot parameter.
COLOPHON
This page is part of release 5.02 of the Linux man-pages project. A
description of the project, information about reporting bugs, and the
latest version of this page, can be found at
https://www.kernel.org/doc/man-pages/.
Linux 2017-09-15 ALLOC_HUGEPAGES(2)