xref: /xnu-8796.141.3/osfmk/man/memory_object_init.html (revision 1b191cb58250d0705d8a51287127505aa4bc0789)
1*1b191cb5SApple OSS Distributions<h2>memory_object_init</h2>
2*1b191cb5SApple OSS Distributions<hr>
3*1b191cb5SApple OSS Distributions<p>
4*1b191cb5SApple OSS Distributions<strong>Server Interface</strong> - Initializes a memory object.
5*1b191cb5SApple OSS Distributions<h3>SYNOPSIS</h3>
6*1b191cb5SApple OSS Distributions<pre>
7*1b191cb5SApple OSS Distributions<strong>kern_return_t   memory_object_init</strong>
8*1b191cb5SApple OSS Distributions		<strong>(memory_object_t</strong>                <var>memory_object</var>,
9*1b191cb5SApple OSS Distributions		 <strong>memory_object_control_t       </strong><var>memory_control</var>,
10*1b191cb5SApple OSS Distributions		 <strong>vm_size_t</strong>            <var>memory_object_page_size</var><strong>);</strong>
11*1b191cb5SApple OSS Distributions
12*1b191cb5SApple OSS Distributions
13*1b191cb5SApple OSS Distributions<strong>kern_return_t   seqnos_memory_object_init</strong>
14*1b191cb5SApple OSS Distributions		<strong>(memory_object_t</strong>                <var>memory_object</var>,
15*1b191cb5SApple OSS Distributions		 <strong>mach_port_seqno_t</strong>                      <var>seqno</var>,
16*1b191cb5SApple OSS Distributions		 <strong>memory_object_control_t</strong>       <var>memory_control</var>,
17*1b191cb5SApple OSS Distributions		 <strong>vm_size_t</strong>            <var>memory_object_page_size</var><strong>);</strong>
18*1b191cb5SApple OSS Distributions</pre>
19*1b191cb5SApple OSS Distributions<h3>PARAMETERS</h3>
20*1b191cb5SApple OSS Distributions<dl>
21*1b191cb5SApple OSS Distributions<dt> <var>memory_object</var>
22*1b191cb5SApple OSS Distributions<dd>
23*1b191cb5SApple OSS Distributions[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*1b191cb5SApple OSS Distributions<p>
25*1b191cb5SApple OSS Distributions<dt> <var>seqno</var>
26*1b191cb5SApple OSS Distributions<dd>
27*1b191cb5SApple OSS Distributions[in scalar] The sequence number of this message relative to the abstract memory object port.
28*1b191cb5SApple OSS Distributions<p>
29*1b191cb5SApple OSS Distributions<dt> <var>memory_control</var>
30*1b191cb5SApple OSS Distributions<dd>
31*1b191cb5SApple OSS Distributions[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*1b191cb5SApple OSS Distributions<p>
33*1b191cb5SApple OSS Distributions<dt> <var>memory_object_page_size</var>
34*1b191cb5SApple OSS Distributions<dd>
35*1b191cb5SApple OSS Distributions[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*1b191cb5SApple OSS Distributions</dl>
37*1b191cb5SApple OSS Distributions<h3>DESCRIPTION</h3>
38*1b191cb5SApple OSS Distributions<p>
39*1b191cb5SApple OSS DistributionsA <strong>memory_object_init</strong> function is called as the result
40*1b191cb5SApple OSS Distributionsof a kernel message notifying a memory manager that the kernel has
41*1b191cb5SApple OSS Distributionsbeen asked to map the specified memory object into a task's virtual
42*1b191cb5SApple OSS Distributionsaddress space.  When asked to map a memory object for the first time,
43*1b191cb5SApple OSS Distributionsthe kernel responds by making a <strong>memory_object_init</strong>
44*1b191cb5SApple OSS Distributionscall on the abstract memory object. This call is provided as a
45*1b191cb5SApple OSS Distributionsconvenience to the memory manager, to allow it to initialize data
46*1b191cb5SApple OSS Distributionsstructures and prepare to receive other requests.
47*1b191cb5SApple OSS Distributions<p>
48*1b191cb5SApple OSS DistributionsIn addition to the
49*1b191cb5SApple OSS Distributionsabstract memory object port itself, the call provides
50*1b191cb5SApple OSS Distributionsa memory cache control port that the memory manager can use to
51*1b191cb5SApple OSS Distributionscontrol use of its data by the kernel. The memory manager gets send
52*1b191cb5SApple OSS Distributionsrights for this port.
53*1b191cb5SApple OSS Distributions<p>
54*1b191cb5SApple OSS DistributionsThe kernel holds send rights for the abstract memory object port, and
55*1b191cb5SApple OSS Distributionsboth send and receive rights for the memory cache control port.
56*1b191cb5SApple OSS DistributionsThe call also supplies the virtual page size to be used for
57*1b191cb5SApple OSS Distributionsthe memory mapping. The memory manager can use this size to detect
58*1b191cb5SApple OSS Distributionsmappings that use different data structures at initialization time, or
59*1b191cb5SApple OSS Distributionsto allocate buffers for use in reading data.
60*1b191cb5SApple OSS Distributions<p>
61*1b191cb5SApple OSS DistributionsIf a memory object is
62*1b191cb5SApple OSS Distributionsmapped into the address space of more than one task on different hosts
63*1b191cb5SApple OSS Distributions(with independent kernels), the memory manager will receive a
64*1b191cb5SApple OSS Distributions<strong>memory_object_init</strong> call from each kernel, containing
65*1b191cb5SApple OSS Distributionsa unique set of control and name ports. Note that each kernel may also
66*1b191cb5SApple OSS Distributionsuse a different page size.
67*1b191cb5SApple OSS Distributions<h3>RETURN VALUES</h3>
68*1b191cb5SApple OSS Distributions<p>
69*1b191cb5SApple OSS Distributions
70*1b191cb5SApple OSS DistributionsAny return value other than <strong>KERN_SUCCESS</strong>
71*1b191cb5SApple OSS Distributionsor <strong>MIG_NO_REPLY</strong>will cause
72*1b191cb5SApple OSS Distributions<strong>mach_msg_server</strong> to remove the memory cache control reference.
73*1b191cb5SApple OSS Distributions<h3>RELATED INFORMATION</h3>
74*1b191cb5SApple OSS Distributions<p>
75*1b191cb5SApple OSS DistributionsFunctions:
76*1b191cb5SApple OSS Distributions<a href="memory_object_terminate.html"><strong>memory_object_terminate</strong></a>.
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