NAME
vm_map_wire,
vm_map_unwire —
manage page wiring within a virtual
memory map
SYNOPSIS
#include
<sys/param.h>
#include <vm/vm.h>
#include <vm/vm_map.h>
int
vm_map_wire(vm_map_t
map, vm_offset_t
start, vm_offset_t
end, int
flags);
int
vm_map_unwire(vm_map_t map,
vm_offset_t start, vm_offset_t
end, int flags);
DESCRIPTION
Thevm_map_wire()
function is responsible for wiring pages in the range between
start and end within the map
map. Wired pages are locked into physical memory, and
may not be paged out as long as their wire count remains above zero.
The
vm_map_unwire()
function performs the corresponding unwire operation.
The flags argument is a bit mask, consisting of the following flags:
If the VM_MAP_WIRE_USER flag is set, the
function operates within user address space.
If the VM_MAP_WIRE_HOLESOK flag is set, it
may operate upon an arbitrary range within the address space of
map.
If a contiguous range is desired, callers should explicitly
express their intent by specifying the
VM_MAP_WIRE_NOHOLES flag.
IMPLEMENTATION NOTES
Both functions will attempt to acquire a lock on the map using
vm_map_lock(9) and hold it for the duration of the call. If
they detect MAP_ENTRY_IN_TRANSITION, they will call
vm_map_unlock_and_wait(9) until the map becomes available
again.
The map could have changed during this window as it was held by another consumer, therefore consumers of this interface should check for this condition using the return values below.
RETURN VALUES
The vm_map_wire() and
vm_map_unwire() functions have identical return
values. The functions return KERN_SUCCESS if all
pages within the range were [un]wired successfully.
Otherwise, if the specified range was not valid, or if the map
changed while the MAP_ENTRY_IN_TRANSITION flag was
set, KERN_INVALID_ADDRESS is returned.
SEE ALSO
AUTHORS
This manual page was written by Bruce M Simpson <bms@spc.org>.