xref: /xnu-10002.61.3/osfmk/man/MO_data_unavailable.html (revision 0f4c859e951fba394238ab619495c4e1d54d0f34)
1*0f4c859eSApple OSS Distributions<h2>memory_object_data_unavailable</h2>
2*0f4c859eSApple OSS Distributions<hr>
3*0f4c859eSApple OSS Distributions<p>
4*0f4c859eSApple OSS Distributions<strong>Function</strong> - Instruct kernel to zero-fill pages as requested data does not exist.
5*0f4c859eSApple OSS Distributions<h3>SYNOPSIS</h3>
6*0f4c859eSApple OSS Distributions<pre>
7*0f4c859eSApple OSS Distributions<strong>kern_return_t   memory_object_data_unavailable</strong>
8*0f4c859eSApple OSS Distributions                <strong>(memory_object_control_t</strong>         <var>memory_control</var>,
9*0f4c859eSApple OSS Distributions                 <strong>vm_offset_t</strong>                             <var>offset</var>,
10*0f4c859eSApple OSS Distributions                 <strong>vm_size_t</strong>                                 <var>size</var><strong>);</strong>
11*0f4c859eSApple OSS Distributions</pre>
12*0f4c859eSApple OSS Distributions<h3>PARAMETERS</h3>
13*0f4c859eSApple OSS Distributions<dl>
14*0f4c859eSApple OSS Distributions<p>
15*0f4c859eSApple OSS Distributions<dt> <var>memory_control</var>
16*0f4c859eSApple OSS Distributions<dd>
17*0f4c859eSApple OSS Distributions[in memory-cache-control send right]
18*0f4c859eSApple OSS DistributionsThe memory cache control port
19*0f4c859eSApple OSS Distributionsto be used by the memory manager for cache management requests.
20*0f4c859eSApple OSS DistributionsThis port is provided by the kernel in a <strong>memory_object_init</strong> or a
21*0f4c859eSApple OSS Distributions<strong>memory_object_create</strong> call.
22*0f4c859eSApple OSS Distributions<p>
23*0f4c859eSApple OSS Distributions<dt> <var>offset</var>
24*0f4c859eSApple OSS Distributions<dd>
25*0f4c859eSApple OSS Distributions[in scalar]
26*0f4c859eSApple OSS DistributionsThe offset within the memory object, in bytes.
27*0f4c859eSApple OSS Distributions<p>
28*0f4c859eSApple OSS Distributions<dt> <var>size</var>
29*0f4c859eSApple OSS Distributions<dd>
30*0f4c859eSApple OSS Distributions[in scalar]
31*0f4c859eSApple OSS DistributionsThe number of bytes of data (starting at <var>offset</var>).  The number
32*0f4c859eSApple OSS Distributionsmust convert to an integral number of memory object pages.
33*0f4c859eSApple OSS Distributions</dl>
34*0f4c859eSApple OSS Distributions<h3>DESCRIPTION</h3>
35*0f4c859eSApple OSS Distributions<p>
36*0f4c859eSApple OSS DistributionsThe <strong>memory_object_data_unavailable</strong> function indicates
37*0f4c859eSApple OSS Distributionsthat the memory
38*0f4c859eSApple OSS Distributionsmanager cannot provide the kernel with the data requested for
39*0f4c859eSApple OSS Distributionsthe given region.
40*0f4c859eSApple OSS DistributionsInstead, the kernel should provide the data for this region.
41*0f4c859eSApple OSS Distributions<p>
42*0f4c859eSApple OSS DistributionsA memory manager can use this call in any of the following situations:
43*0f4c859eSApple OSS Distributions<ul>
44*0f4c859eSApple OSS Distributions<li>
45*0f4c859eSApple OSS DistributionsWhen the object was created by the kernel
46*0f4c859eSApple OSS Distributions(via <strong>memory_object_create</strong>) and
47*0f4c859eSApple OSS Distributionsthe kernel has not yet provided data for the region (via either
48*0f4c859eSApple OSS Distributions<strong>memory_object_data_initialize</strong> or <strong>memory_object_data_return</strong>).
49*0f4c859eSApple OSS DistributionsIn this case, the
50*0f4c859eSApple OSS Distributionsobject is a temporary memory object; the memory manager is the default
51*0f4c859eSApple OSS Distributionsmemory manager; and the kernel should provide zero-filled pages for the
52*0f4c859eSApple OSS Distributionsobject.
53*0f4c859eSApple OSS Distributions     <p>
54*0f4c859eSApple OSS Distributions<li>
55*0f4c859eSApple OSS DistributionsWhen the object is a normal user-created memory object.  In this case, the
56*0f4c859eSApple OSS Distributionskernel should provide zero-filled pages for the region.
57*0f4c859eSApple OSS Distributions</ul>
58*0f4c859eSApple OSS Distributions<h3>RETURN VALUES</h3>
59*0f4c859eSApple OSS Distributions<p>
60*0f4c859eSApple OSS DistributionsOnly generic errors apply.
61*0f4c859eSApple OSS Distributions<h3>RELATED INFORMATION</h3>
62*0f4c859eSApple OSS Distributions<p>
63*0f4c859eSApple OSS DistributionsFunctions:
64*0f4c859eSApple OSS Distributions<a href="memory_object_create.html"><strong>memory_object_create</strong></a>,
65*0f4c859eSApple OSS Distributions<a href="memory_object_data_error.html"><strong>memory_object_data_error</strong></a>,
66*0f4c859eSApple OSS Distributions<a href="memory_object_data_request.html"><strong>memory_object_data_request</strong></a>,
67*0f4c859eSApple OSS Distributions<a href="memory_object_data_supply.html"><strong>memory_object_data_supply</strong></a>.
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