определить, находятся ли страницы в памяти (determine whether pages are resident in memory)
Имя (Name)
mincore - determine whether pages are resident in memory
Синопсис (Synopsis)
#include <sys/mman.h>
int mincore(void *addr, size_t length, unsigned char *vec);
Feature Test Macro Requirements for glibc (see
feature_test_macros(7)):
mincore():
Since glibc 2.19:
_DEFAULT_SOURCE
Glibc 2.19 and earlier:
_BSD_SOURCE || _SVID_SOURCE
Описание (Description)
mincore() returns a vector that indicates whether pages of the
calling process's virtual memory are resident in core (RAM), and
so will not cause a disk access (page fault) if referenced. The
kernel returns residency information about the pages starting at
the address addr, and continuing for length bytes.
The addr argument must be a multiple of the system page size.
The length argument need not be a multiple of the page size, but
since residency information is returned for whole pages, length
is effectively rounded up to the next multiple of the page size.
One may obtain the page size (PAGE_SIZE) using
sysconf(_SC_PAGESIZE).
The vec argument must point to an array containing at least
(length+PAGE_SIZE-1) / PAGE_SIZE bytes. On return, the least
significant bit of each byte will be set if the corresponding
page is currently resident in memory, and be clear otherwise.
(The settings of the other bits in each byte are undefined; these
bits are reserved for possible later use.) Of course the
information returned in vec is only a snapshot: pages that are
not locked in memory can come and go at any moment, and the
contents of vec may already be stale by the time this call
returns.
Возвращаемое значение (Return value)
On success, mincore() returns zero. On error, -1 is returned,
and errno is set to indicate the error.
Ошибки (Error)
EAGAIN kernel is temporarily out of resources.
EFAULT vec points to an invalid address.
EINVAL addr is not a multiple of the page size.
ENOMEM length is greater than (TASK_SIZE - addr). (This could
occur if a negative value is specified for length, since
that value will be interpreted as a large unsigned
integer.) In Linux 2.6.11 and earlier, the error EINVAL
was returned for this condition.
ENOMEM addr to addr + length contained unmapped memory.
Версии (Versions)
Available since Linux 2.3.99pre1 and glibc 2.2.
Стандарты (Conforming to)
mincore() is not specified in POSIX.1, and it is not available on
all UNIX implementations.
Ошибки (баги) (Bugs)
Before kernel 2.6.21, mincore() did not return correct
information for MAP_PRIVATE mappings, or for nonlinear mappings
(established using remap_file_pages(2)).
Смотри также (See also)
fincore(1), madvise(2), mlock(2), mmap(2), posix_fadvise(2),
posix_madvise(3)
