vm_map_findspace(9)

vm_map_findspace9

Find a free region within a map

Usage

#include <sys/param.h>

#include <vm/vm.h>

#include <vm/vm_map.h>

int

vm_map_findspace(vm_map_t map, vm_offset_t start, vm_size_t length, vm_offset_t *addr);

Overview

The vm_map_findspace() function attempts to find a region with sufficient space in the map for an object of size length at the address addr.

Implementation notes

It is the caller's responsibility to obtain a lock on the map using vm_map_lock(9) before calling this function.

This routine may call pmap_growkernel(9) to grow the kernel's address space, if and only if the mapping is being made within the kernel address space, and if insufficient space remains in the kernel_map.

Return values

The vm_map_findspace() function returns the value 0 if successful, and *addr will contain the first virtual address in the found region; otherwise, the value 1 is returned.

Releases

54 releases since FreeBSD 5.2-RELEASE; the text changed 34 times.

  1. 5.2–5.2.1
  2. 5.3–5.5
  3. 6.0–6.3
  4. 6.4
  5. 7.0
  6. 7.1
  7. 7.2
  8. 7.3
  9. 7.4
  10. 8.0
  11. 8.1
  12. 8.2
  13. 8.3
  14. 8.4
  15. 9.0
  16. 9.1
  17. 9.2
  18. 9.3
  19. 10.0
  20. 10.1
  21. 10.2
  22. 10.3
  23. 10.4
  24. 11.0
  25. 11.1
  26. 11.2
  27. 11.3
  28. 11.4
  29. 12.0
  30. 12.1
  31. 12.2
  32. 12.3
  33. 12.4
  34. 13.0–13.2
  35. 13.3–16.0

Authors

This manual page was written by Bruce M Simpson ⟨[email protected]⟩.

From base 16.0-CURRENT-20261027-61c70dc16a79 in FreeBSD 16.0-CURRENT (2026-10-27). Parsed by carta from the page's mdoc source.