xref: /xnu-8792.81.2/osfmk/man/MO_data_unavailable.html (revision 19c3b8c28c31cb8130e034cfb5df6bf9ba342d90)
1*19c3b8c2SApple OSS Distributions<h2>memory_object_data_unavailable</h2>
2*19c3b8c2SApple OSS Distributions<hr>
3*19c3b8c2SApple OSS Distributions<p>
4*19c3b8c2SApple OSS Distributions<strong>Function</strong> - Instruct kernel to zero-fill pages as requested data does not exist.
5*19c3b8c2SApple OSS Distributions<h3>SYNOPSIS</h3>
6*19c3b8c2SApple OSS Distributions<pre>
7*19c3b8c2SApple OSS Distributions<strong>kern_return_t   memory_object_data_unavailable</strong>
8*19c3b8c2SApple OSS Distributions                <strong>(memory_object_control_t</strong>         <var>memory_control</var>,
9*19c3b8c2SApple OSS Distributions                 <strong>vm_offset_t</strong>                             <var>offset</var>,
10*19c3b8c2SApple OSS Distributions                 <strong>vm_size_t</strong>                                 <var>size</var><strong>);</strong>
11*19c3b8c2SApple OSS Distributions</pre>
12*19c3b8c2SApple OSS Distributions<h3>PARAMETERS</h3>
13*19c3b8c2SApple OSS Distributions<dl>
14*19c3b8c2SApple OSS Distributions<p>
15*19c3b8c2SApple OSS Distributions<dt> <var>memory_control</var>
16*19c3b8c2SApple OSS Distributions<dd>
17*19c3b8c2SApple OSS Distributions[in memory-cache-control send right]
18*19c3b8c2SApple OSS DistributionsThe memory cache control port
19*19c3b8c2SApple OSS Distributionsto be used by the memory manager for cache management requests.
20*19c3b8c2SApple OSS DistributionsThis port is provided by the kernel in a <strong>memory_object_init</strong> or a
21*19c3b8c2SApple OSS Distributions<strong>memory_object_create</strong> call.
22*19c3b8c2SApple OSS Distributions<p>
23*19c3b8c2SApple OSS Distributions<dt> <var>offset</var>
24*19c3b8c2SApple OSS Distributions<dd>
25*19c3b8c2SApple OSS Distributions[in scalar]
26*19c3b8c2SApple OSS DistributionsThe offset within the memory object, in bytes.
27*19c3b8c2SApple OSS Distributions<p>
28*19c3b8c2SApple OSS Distributions<dt> <var>size</var>
29*19c3b8c2SApple OSS Distributions<dd>
30*19c3b8c2SApple OSS Distributions[in scalar]
31*19c3b8c2SApple OSS DistributionsThe number of bytes of data (starting at <var>offset</var>).  The number
32*19c3b8c2SApple OSS Distributionsmust convert to an integral number of memory object pages.
33*19c3b8c2SApple OSS Distributions</dl>
34*19c3b8c2SApple OSS Distributions<h3>DESCRIPTION</h3>
35*19c3b8c2SApple OSS Distributions<p>
36*19c3b8c2SApple OSS DistributionsThe <strong>memory_object_data_unavailable</strong> function indicates
37*19c3b8c2SApple OSS Distributionsthat the memory
38*19c3b8c2SApple OSS Distributionsmanager cannot provide the kernel with the data requested for
39*19c3b8c2SApple OSS Distributionsthe given region.
40*19c3b8c2SApple OSS DistributionsInstead, the kernel should provide the data for this region.
41*19c3b8c2SApple OSS Distributions<p>
42*19c3b8c2SApple OSS DistributionsA memory manager can use this call in any of the following situations:
43*19c3b8c2SApple OSS Distributions<ul>
44*19c3b8c2SApple OSS Distributions<li>
45*19c3b8c2SApple OSS DistributionsWhen the object was created by the kernel
46*19c3b8c2SApple OSS Distributions(via <strong>memory_object_create</strong>) and
47*19c3b8c2SApple OSS Distributionsthe kernel has not yet provided data for the region (via either
48*19c3b8c2SApple OSS Distributions<strong>memory_object_data_initialize</strong> or <strong>memory_object_data_return</strong>).
49*19c3b8c2SApple OSS DistributionsIn this case, the
50*19c3b8c2SApple OSS Distributionsobject is a temporary memory object; the memory manager is the default
51*19c3b8c2SApple OSS Distributionsmemory manager; and the kernel should provide zero-filled pages for the
52*19c3b8c2SApple OSS Distributionsobject.
53*19c3b8c2SApple OSS Distributions     <p>
54*19c3b8c2SApple OSS Distributions<li>
55*19c3b8c2SApple OSS DistributionsWhen the object is a normal user-created memory object.  In this case, the
56*19c3b8c2SApple OSS Distributionskernel should provide zero-filled pages for the region.
57*19c3b8c2SApple OSS Distributions</ul>
58*19c3b8c2SApple OSS Distributions<h3>RETURN VALUES</h3>
59*19c3b8c2SApple OSS Distributions<p>
60*19c3b8c2SApple OSS DistributionsOnly generic errors apply.
61*19c3b8c2SApple OSS Distributions<h3>RELATED INFORMATION</h3>
62*19c3b8c2SApple OSS Distributions<p>
63*19c3b8c2SApple OSS DistributionsFunctions:
64*19c3b8c2SApple OSS Distributions<a href="memory_object_create.html"><strong>memory_object_create</strong></a>,
65*19c3b8c2SApple OSS Distributions<a href="memory_object_data_error.html"><strong>memory_object_data_error</strong></a>,
66*19c3b8c2SApple OSS Distributions<a href="memory_object_data_request.html"><strong>memory_object_data_request</strong></a>,
67*19c3b8c2SApple OSS Distributions<a href="memory_object_data_supply.html"><strong>memory_object_data_supply</strong></a>.
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