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

       The  vm_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

       mlockall(2), munlockall(2), vm_map(9)

AUTHORS

       This manual page was written by Bruce M Simpson <bms@spc.org>.

Debian                                            July 19, 2003                                   VM_MAP_WIRE(9)