osfmk/man/memory_object_init.html

   1 <h2>memory_object_init</h2>
   2 <hr>
   3 <p>
   4 <strong>Server Interface</strong> - Initializes a memory object.
   5 <h3>SYNOPSIS</h3>
   6 <pre>
   7 <strong>kern_return_t   memory_object_init</strong>
   8                 <strong>(memory_object_t</strong>                <var>memory_object</var>,
   9                  <strong>memory_object_control_t       </strong><var>memory_control</var>,
  10                  <strong>vm_size_t</strong>            <var>memory_object_page_size</var><strong>);</strong>
  11
  12
  13 <strong>kern_return_t   seqnos_memory_object_init</strong>
  14                 <strong>(memory_object_t</strong>                <var>memory_object</var>,
  15                  <strong>mach_port_seqno_t</strong>                      <var>seqno</var>,
  16                  <strong>memory_object_control_t</strong>       <var>memory_control</var>,
  17                  <strong>vm_size_t</strong>            <var>memory_object_page_size</var><strong>);</strong>
  18 </pre>
  19 <h3>PARAMETERS</h3>
  20 <dl>
  21 <dt> <var>memory_object</var>
  22 <dd>
  23 [in abstract-memory-object port] The abstract memory object port that represents the memory object data, as supplied to the kernel in a vm_map call.
  24 <p>
  25 <dt> <var>seqno</var>
  26 <dd>
  27 [in scalar] The sequence number of this message relative to the abstract memory object port.
  28 <p>
  29 <dt> <var>memory_control</var>
  30 <dd>
  31 [in memory-cache-control port] The memory cache control port to be used by the memory manager. If the memory object has been supplied to more than one kernel, this parameter identifies the kernel that is making the call.
  32 <p>
  33 <dt> <var>memory_object_page_size</var>
  34 <dd>
  35 [in scalar] The page size used by the kernel. All calls involving this kernel must use data sizes that are integral multiples of this page size.
  36 </dl>
  37 <h3>DESCRIPTION</h3>
  38 <p>
  39 A <strong>memory_object_init</strong> function is called as the result
  40 of a kernel message notifying a memory manager that the kernel has
  41 been asked to map the specified memory object into a task's virtual
  42 address space.  When asked to map a memory object for the first time,
  43 the kernel responds by making a <strong>memory_object_init</strong>
  44 call on the abstract memory object. This call is provided as a
  45 convenience to the memory manager, to allow it to initialize data
  46 structures and prepare to receive other requests.
  47 <p>
  48 In addition to the
  49 abstract memory object port itself, the call provides
  50 a memory cache control port that the memory manager can use to
  51 control use of its data by the kernel. The memory manager gets send
  52 rights for this port.
  53 <p>
  54 The kernel holds send rights for the abstract memory object port, and
  55 both send and receive rights for the memory cache control port.
  56 The call also supplies the virtual page size to be used for
  57 the memory mapping. The memory manager can use this size to detect
  58 mappings that use different data structures at initialization time, or
  59 to allocate buffers for use in reading data.
  60 <p>
  61 If a memory object is
  62 mapped into the address space of more than one task on different hosts
  63 (with independent kernels), the memory manager will receive a
  64 <strong>memory_object_init</strong> call from each kernel, containing
  65 a unique set of control and name ports. Note that each kernel may also
  66 use a different page size.
  67 <h3>RETURN VALUES</h3>
  68 <p>
  69
  70 Any return value other than <strong>KERN_SUCCESS</strong>
  71 or <strong>MIG_NO_REPLY</strong>will cause
  72 <strong>mach_msg_server</strong> to remove the memory cache control reference.
  73 <h3>RELATED INFORMATION</h3>
  74 <p>
  75 Functions:
  76 <a href="memory_object_terminate.html"><strong>memory_object_terminate</strong></a>.