NAME¶

vm_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 incremented 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 function 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 successfully 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 ALSO¶

vm_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⟩.