xref: /xnu-10002.41.9/osfmk/man/MO_data_unavailable.html (revision 699cd48037512bf4380799317ca44ca453c82f57)
1*699cd480SApple OSS Distributions<h2>memory_object_data_unavailable</h2>
2*699cd480SApple OSS Distributions<hr>
3*699cd480SApple OSS Distributions<p>
4*699cd480SApple OSS Distributions<strong>Function</strong> - Instruct kernel to zero-fill pages as requested data does not exist.
5*699cd480SApple OSS Distributions<h3>SYNOPSIS</h3>
6*699cd480SApple OSS Distributions<pre>
7*699cd480SApple OSS Distributions<strong>kern_return_t   memory_object_data_unavailable</strong>
8*699cd480SApple OSS Distributions                <strong>(memory_object_control_t</strong>         <var>memory_control</var>,
9*699cd480SApple OSS Distributions                 <strong>vm_offset_t</strong>                             <var>offset</var>,
10*699cd480SApple OSS Distributions                 <strong>vm_size_t</strong>                                 <var>size</var><strong>);</strong>
11*699cd480SApple OSS Distributions</pre>
12*699cd480SApple OSS Distributions<h3>PARAMETERS</h3>
13*699cd480SApple OSS Distributions<dl>
14*699cd480SApple OSS Distributions<p>
15*699cd480SApple OSS Distributions<dt> <var>memory_control</var>
16*699cd480SApple OSS Distributions<dd>
17*699cd480SApple OSS Distributions[in memory-cache-control send right]
18*699cd480SApple OSS DistributionsThe memory cache control port
19*699cd480SApple OSS Distributionsto be used by the memory manager for cache management requests.
20*699cd480SApple OSS DistributionsThis port is provided by the kernel in a <strong>memory_object_init</strong> or a
21*699cd480SApple OSS Distributions<strong>memory_object_create</strong> call.
22*699cd480SApple OSS Distributions<p>
23*699cd480SApple OSS Distributions<dt> <var>offset</var>
24*699cd480SApple OSS Distributions<dd>
25*699cd480SApple OSS Distributions[in scalar]
26*699cd480SApple OSS DistributionsThe offset within the memory object, in bytes.
27*699cd480SApple OSS Distributions<p>
28*699cd480SApple OSS Distributions<dt> <var>size</var>
29*699cd480SApple OSS Distributions<dd>
30*699cd480SApple OSS Distributions[in scalar]
31*699cd480SApple OSS DistributionsThe number of bytes of data (starting at <var>offset</var>).  The number
32*699cd480SApple OSS Distributionsmust convert to an integral number of memory object pages.
33*699cd480SApple OSS Distributions</dl>
34*699cd480SApple OSS Distributions<h3>DESCRIPTION</h3>
35*699cd480SApple OSS Distributions<p>
36*699cd480SApple OSS DistributionsThe <strong>memory_object_data_unavailable</strong> function indicates
37*699cd480SApple OSS Distributionsthat the memory
38*699cd480SApple OSS Distributionsmanager cannot provide the kernel with the data requested for
39*699cd480SApple OSS Distributionsthe given region.
40*699cd480SApple OSS DistributionsInstead, the kernel should provide the data for this region.
41*699cd480SApple OSS Distributions<p>
42*699cd480SApple OSS DistributionsA memory manager can use this call in any of the following situations:
43*699cd480SApple OSS Distributions<ul>
44*699cd480SApple OSS Distributions<li>
45*699cd480SApple OSS DistributionsWhen the object was created by the kernel
46*699cd480SApple OSS Distributions(via <strong>memory_object_create</strong>) and
47*699cd480SApple OSS Distributionsthe kernel has not yet provided data for the region (via either
48*699cd480SApple OSS Distributions<strong>memory_object_data_initialize</strong> or <strong>memory_object_data_return</strong>).
49*699cd480SApple OSS DistributionsIn this case, the
50*699cd480SApple OSS Distributionsobject is a temporary memory object; the memory manager is the default
51*699cd480SApple OSS Distributionsmemory manager; and the kernel should provide zero-filled pages for the
52*699cd480SApple OSS Distributionsobject.
53*699cd480SApple OSS Distributions     <p>
54*699cd480SApple OSS Distributions<li>
55*699cd480SApple OSS DistributionsWhen the object is a normal user-created memory object.  In this case, the
56*699cd480SApple OSS Distributionskernel should provide zero-filled pages for the region.
57*699cd480SApple OSS Distributions</ul>
58*699cd480SApple OSS Distributions<h3>RETURN VALUES</h3>
59*699cd480SApple OSS Distributions<p>
60*699cd480SApple OSS DistributionsOnly generic errors apply.
61*699cd480SApple OSS Distributions<h3>RELATED INFORMATION</h3>
62*699cd480SApple OSS Distributions<p>
63*699cd480SApple OSS DistributionsFunctions:
64*699cd480SApple OSS Distributions<a href="memory_object_create.html"><strong>memory_object_create</strong></a>,
65*699cd480SApple OSS Distributions<a href="memory_object_data_error.html"><strong>memory_object_data_error</strong></a>,
66*699cd480SApple OSS Distributions<a href="memory_object_data_request.html"><strong>memory_object_data_request</strong></a>,
67*699cd480SApple OSS Distributions<a href="memory_object_data_supply.html"><strong>memory_object_data_supply</strong></a>.
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