xref: /xnu-10063.121.3/osfmk/man/MO_data_unavailable.html (revision 2c2f96dc2b9a4408a43d3150ae9c105355ca3daa)
1*2c2f96dcSApple OSS Distributions<h2>memory_object_data_unavailable</h2>
2*2c2f96dcSApple OSS Distributions<hr>
3*2c2f96dcSApple OSS Distributions<p>
4*2c2f96dcSApple OSS Distributions<strong>Function</strong> - Instruct kernel to zero-fill pages as requested data does not exist.
5*2c2f96dcSApple OSS Distributions<h3>SYNOPSIS</h3>
6*2c2f96dcSApple OSS Distributions<pre>
7*2c2f96dcSApple OSS Distributions<strong>kern_return_t   memory_object_data_unavailable</strong>
8*2c2f96dcSApple OSS Distributions                <strong>(memory_object_control_t</strong>         <var>memory_control</var>,
9*2c2f96dcSApple OSS Distributions                 <strong>vm_offset_t</strong>                             <var>offset</var>,
10*2c2f96dcSApple OSS Distributions                 <strong>vm_size_t</strong>                                 <var>size</var><strong>);</strong>
11*2c2f96dcSApple OSS Distributions</pre>
12*2c2f96dcSApple OSS Distributions<h3>PARAMETERS</h3>
13*2c2f96dcSApple OSS Distributions<dl>
14*2c2f96dcSApple OSS Distributions<p>
15*2c2f96dcSApple OSS Distributions<dt> <var>memory_control</var>
16*2c2f96dcSApple OSS Distributions<dd>
17*2c2f96dcSApple OSS Distributions[in memory-cache-control send right]
18*2c2f96dcSApple OSS DistributionsThe memory cache control port
19*2c2f96dcSApple OSS Distributionsto be used by the memory manager for cache management requests.
20*2c2f96dcSApple OSS DistributionsThis port is provided by the kernel in a <strong>memory_object_init</strong> or a
21*2c2f96dcSApple OSS Distributions<strong>memory_object_create</strong> call.
22*2c2f96dcSApple OSS Distributions<p>
23*2c2f96dcSApple OSS Distributions<dt> <var>offset</var>
24*2c2f96dcSApple OSS Distributions<dd>
25*2c2f96dcSApple OSS Distributions[in scalar]
26*2c2f96dcSApple OSS DistributionsThe offset within the memory object, in bytes.
27*2c2f96dcSApple OSS Distributions<p>
28*2c2f96dcSApple OSS Distributions<dt> <var>size</var>
29*2c2f96dcSApple OSS Distributions<dd>
30*2c2f96dcSApple OSS Distributions[in scalar]
31*2c2f96dcSApple OSS DistributionsThe number of bytes of data (starting at <var>offset</var>).  The number
32*2c2f96dcSApple OSS Distributionsmust convert to an integral number of memory object pages.
33*2c2f96dcSApple OSS Distributions</dl>
34*2c2f96dcSApple OSS Distributions<h3>DESCRIPTION</h3>
35*2c2f96dcSApple OSS Distributions<p>
36*2c2f96dcSApple OSS DistributionsThe <strong>memory_object_data_unavailable</strong> function indicates
37*2c2f96dcSApple OSS Distributionsthat the memory
38*2c2f96dcSApple OSS Distributionsmanager cannot provide the kernel with the data requested for
39*2c2f96dcSApple OSS Distributionsthe given region.
40*2c2f96dcSApple OSS DistributionsInstead, the kernel should provide the data for this region.
41*2c2f96dcSApple OSS Distributions<p>
42*2c2f96dcSApple OSS DistributionsA memory manager can use this call in any of the following situations:
43*2c2f96dcSApple OSS Distributions<ul>
44*2c2f96dcSApple OSS Distributions<li>
45*2c2f96dcSApple OSS DistributionsWhen the object was created by the kernel
46*2c2f96dcSApple OSS Distributions(via <strong>memory_object_create</strong>) and
47*2c2f96dcSApple OSS Distributionsthe kernel has not yet provided data for the region (via either
48*2c2f96dcSApple OSS Distributions<strong>memory_object_data_initialize</strong> or <strong>memory_object_data_return</strong>).
49*2c2f96dcSApple OSS DistributionsIn this case, the
50*2c2f96dcSApple OSS Distributionsobject is a temporary memory object; the memory manager is the default
51*2c2f96dcSApple OSS Distributionsmemory manager; and the kernel should provide zero-filled pages for the
52*2c2f96dcSApple OSS Distributionsobject.
53*2c2f96dcSApple OSS Distributions     <p>
54*2c2f96dcSApple OSS Distributions<li>
55*2c2f96dcSApple OSS DistributionsWhen the object is a normal user-created memory object.  In this case, the
56*2c2f96dcSApple OSS Distributionskernel should provide zero-filled pages for the region.
57*2c2f96dcSApple OSS Distributions</ul>
58*2c2f96dcSApple OSS Distributions<h3>RETURN VALUES</h3>
59*2c2f96dcSApple OSS Distributions<p>
60*2c2f96dcSApple OSS DistributionsOnly generic errors apply.
61*2c2f96dcSApple OSS Distributions<h3>RELATED INFORMATION</h3>
62*2c2f96dcSApple OSS Distributions<p>
63*2c2f96dcSApple OSS DistributionsFunctions:
64*2c2f96dcSApple OSS Distributions<a href="memory_object_create.html"><strong>memory_object_create</strong></a>,
65*2c2f96dcSApple OSS Distributions<a href="memory_object_data_error.html"><strong>memory_object_data_error</strong></a>,
66*2c2f96dcSApple OSS Distributions<a href="memory_object_data_request.html"><strong>memory_object_data_request</strong></a>,
67*2c2f96dcSApple OSS Distributions<a href="memory_object_data_supply.html"><strong>memory_object_data_supply</strong></a>.
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