xref: /xnu-8796.121.2/osfmk/man/MO_data_unavailable.html (revision c54f35ca767986246321eb901baf8f5ff7923f6a)
1*c54f35caSApple OSS Distributions<h2>memory_object_data_unavailable</h2>
2*c54f35caSApple OSS Distributions<hr>
3*c54f35caSApple OSS Distributions<p>
4*c54f35caSApple OSS Distributions<strong>Function</strong> - Instruct kernel to zero-fill pages as requested data does not exist.
5*c54f35caSApple OSS Distributions<h3>SYNOPSIS</h3>
6*c54f35caSApple OSS Distributions<pre>
7*c54f35caSApple OSS Distributions<strong>kern_return_t   memory_object_data_unavailable</strong>
8*c54f35caSApple OSS Distributions                <strong>(memory_object_control_t</strong>         <var>memory_control</var>,
9*c54f35caSApple OSS Distributions                 <strong>vm_offset_t</strong>                             <var>offset</var>,
10*c54f35caSApple OSS Distributions                 <strong>vm_size_t</strong>                                 <var>size</var><strong>);</strong>
11*c54f35caSApple OSS Distributions</pre>
12*c54f35caSApple OSS Distributions<h3>PARAMETERS</h3>
13*c54f35caSApple OSS Distributions<dl>
14*c54f35caSApple OSS Distributions<p>
15*c54f35caSApple OSS Distributions<dt> <var>memory_control</var>
16*c54f35caSApple OSS Distributions<dd>
17*c54f35caSApple OSS Distributions[in memory-cache-control send right]
18*c54f35caSApple OSS DistributionsThe memory cache control port
19*c54f35caSApple OSS Distributionsto be used by the memory manager for cache management requests.
20*c54f35caSApple OSS DistributionsThis port is provided by the kernel in a <strong>memory_object_init</strong> or a
21*c54f35caSApple OSS Distributions<strong>memory_object_create</strong> call.
22*c54f35caSApple OSS Distributions<p>
23*c54f35caSApple OSS Distributions<dt> <var>offset</var>
24*c54f35caSApple OSS Distributions<dd>
25*c54f35caSApple OSS Distributions[in scalar]
26*c54f35caSApple OSS DistributionsThe offset within the memory object, in bytes.
27*c54f35caSApple OSS Distributions<p>
28*c54f35caSApple OSS Distributions<dt> <var>size</var>
29*c54f35caSApple OSS Distributions<dd>
30*c54f35caSApple OSS Distributions[in scalar]
31*c54f35caSApple OSS DistributionsThe number of bytes of data (starting at <var>offset</var>).  The number
32*c54f35caSApple OSS Distributionsmust convert to an integral number of memory object pages.
33*c54f35caSApple OSS Distributions</dl>
34*c54f35caSApple OSS Distributions<h3>DESCRIPTION</h3>
35*c54f35caSApple OSS Distributions<p>
36*c54f35caSApple OSS DistributionsThe <strong>memory_object_data_unavailable</strong> function indicates
37*c54f35caSApple OSS Distributionsthat the memory
38*c54f35caSApple OSS Distributionsmanager cannot provide the kernel with the data requested for
39*c54f35caSApple OSS Distributionsthe given region.
40*c54f35caSApple OSS DistributionsInstead, the kernel should provide the data for this region.
41*c54f35caSApple OSS Distributions<p>
42*c54f35caSApple OSS DistributionsA memory manager can use this call in any of the following situations:
43*c54f35caSApple OSS Distributions<ul>
44*c54f35caSApple OSS Distributions<li>
45*c54f35caSApple OSS DistributionsWhen the object was created by the kernel
46*c54f35caSApple OSS Distributions(via <strong>memory_object_create</strong>) and
47*c54f35caSApple OSS Distributionsthe kernel has not yet provided data for the region (via either
48*c54f35caSApple OSS Distributions<strong>memory_object_data_initialize</strong> or <strong>memory_object_data_return</strong>).
49*c54f35caSApple OSS DistributionsIn this case, the
50*c54f35caSApple OSS Distributionsobject is a temporary memory object; the memory manager is the default
51*c54f35caSApple OSS Distributionsmemory manager; and the kernel should provide zero-filled pages for the
52*c54f35caSApple OSS Distributionsobject.
53*c54f35caSApple OSS Distributions     <p>
54*c54f35caSApple OSS Distributions<li>
55*c54f35caSApple OSS DistributionsWhen the object is a normal user-created memory object.  In this case, the
56*c54f35caSApple OSS Distributionskernel should provide zero-filled pages for the region.
57*c54f35caSApple OSS Distributions</ul>
58*c54f35caSApple OSS Distributions<h3>RETURN VALUES</h3>
59*c54f35caSApple OSS Distributions<p>
60*c54f35caSApple OSS DistributionsOnly generic errors apply.
61*c54f35caSApple OSS Distributions<h3>RELATED INFORMATION</h3>
62*c54f35caSApple OSS Distributions<p>
63*c54f35caSApple OSS DistributionsFunctions:
64*c54f35caSApple OSS Distributions<a href="memory_object_create.html"><strong>memory_object_create</strong></a>,
65*c54f35caSApple OSS Distributions<a href="memory_object_data_error.html"><strong>memory_object_data_error</strong></a>,
66*c54f35caSApple OSS Distributions<a href="memory_object_data_request.html"><strong>memory_object_data_request</strong></a>,
67*c54f35caSApple OSS Distributions<a href="memory_object_data_supply.html"><strong>memory_object_data_supply</strong></a>.
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