VM_MAP_FIND(9) BSD Kernel Developer's Manual VM_MAP_FIND(9)NAMEvm_map_find — find a free region within a map, and optionally map a
vm_object
SYNOPSIS
#include <sys/param.h>
#include <vm/vm.h>
#include <vm/vm_map.h>
int
vm_map_find(vm_map_t map, vm_object_t object, vm_ooffset_t offset,
vm_offset_t *addr, vm_size_t length, int find_space, vm_prot_t prot,
vm_prot_t max, int cow);
DESCRIPTION
The vm_map_find() function attempts to find a free region in the target
map, with the given length, and will also optionally create a mapping of
object.
The arguments offset, prot, max, and cow are passed unchanged to
vm_map_insert(9) when creating the mapping, if and only if a free region
is found.
If object is non-NULL, the reference count on the object must be incre‐
mented by the caller before calling this function to account for the new
entry.
If find_space is either VMFS_ALIGNED_SPACE or VMFS_ANY_SPACE, the func‐
tion will call vm_map_findspace(9) to discover a free region. Moreover,
if find_space is VMFS_ALIGNED_SPACE, the address of the free region will
be optimized for the use of superpages. Otherwise, if find_space is
VMFS_NO_SPACE, vm_map_insert(9) is called with the given address, addr.
IMPLEMENTATION NOTES
This function acquires a lock on map by calling vm_map_lock(9), and holds
it until the function returns.
The search for a free region is defined to be first-fit, from the address
addr onwards.
RETURN VALUES
The vm_map_find() function returns KERN_SUCCESS if the mapping was suc‐
cessfully created. If space could not be found or find_space was
VMFS_NO_SPACE and the given address, addr, was already mapped,
KERN_NO_SPACE will be returned. If the discovered range turned out to be
bogus, KERN_INVALID_ADDRESS will be returned.
SEE ALSOvm_map(9), vm_map_findspace(9), vm_map_insert(9), vm_map_lock(9)AUTHORS
This manual page was written by Bruce M Simpson ⟨bms@spc.org⟩.
BSD May 10, 2008 BSD
