The
mincore()
system call determines whether each of the pages in the region beginning at
addr
and continuing for
len
bytes is resident or mapped, depending on the value of sysctl
vm.mincore_mapped.
The status is returned in the
vec
array, one character per page.
Each character is either 0 if the page is not resident, or a combination of
the following flags (defined in
<sys/mman.h>):
|
| MINCORE_INCORE
|
Page is in core (resident).
|
| MINCORE_REFERENCED
|
Page has been referenced by us.
|
| MINCORE_MODIFIED
|
Page has been modified by us.
|
| MINCORE_REFERENCED_OTHER
|
| |
Page has been referenced.
|
| MINCORE_MODIFIED_OTHER
|
Page has been modified.
|
| MINCORE_SUPER
|
Page is part of a large
("super")
page.
|
|
The information returned by
mincore()
may be out of date by the time the system call returns.
The only way to ensure that a page is resident is to lock it into memory
with the
mlock(2)
system call.
If the
vm.mincore_mapped
sysctl is set to a non-zero value (default), only the current process'
mappings of the pages in the specified virtual address range are examined.
This does not preclude the system from returning
MINCORE_REFERENCED_OTHER
and
MINCORE_MODIFIED_OTHER
statuses.
Otherwise, if the sysctl value is zero, all resident pages backing the
specified address range are examined, regardless of the mapping state.
