xref: /xnu-11215.41.3/osfmk/man/MO_data_unavailable.html (revision 33de042d024d46de5ff4e89f2471de6608e37fa4)
1*33de042dSApple OSS Distributions<h2>memory_object_data_unavailable</h2>
2*33de042dSApple OSS Distributions<hr>
3*33de042dSApple OSS Distributions<p>
4*33de042dSApple OSS Distributions<strong>Function</strong> - Instruct kernel to zero-fill pages as requested data does not exist.
5*33de042dSApple OSS Distributions<h3>SYNOPSIS</h3>
6*33de042dSApple OSS Distributions<pre>
7*33de042dSApple OSS Distributions<strong>kern_return_t   memory_object_data_unavailable</strong>
8*33de042dSApple OSS Distributions                <strong>(memory_object_control_t</strong>         <var>memory_control</var>,
9*33de042dSApple OSS Distributions                 <strong>vm_offset_t</strong>                             <var>offset</var>,
10*33de042dSApple OSS Distributions                 <strong>vm_size_t</strong>                                 <var>size</var><strong>);</strong>
11*33de042dSApple OSS Distributions</pre>
12*33de042dSApple OSS Distributions<h3>PARAMETERS</h3>
13*33de042dSApple OSS Distributions<dl>
14*33de042dSApple OSS Distributions<p>
15*33de042dSApple OSS Distributions<dt> <var>memory_control</var>
16*33de042dSApple OSS Distributions<dd>
17*33de042dSApple OSS Distributions[in memory-cache-control send right]
18*33de042dSApple OSS DistributionsThe memory cache control port
19*33de042dSApple OSS Distributionsto be used by the memory manager for cache management requests.
20*33de042dSApple OSS DistributionsThis port is provided by the kernel in a <strong>memory_object_init</strong> or a
21*33de042dSApple OSS Distributions<strong>memory_object_create</strong> call.
22*33de042dSApple OSS Distributions<p>
23*33de042dSApple OSS Distributions<dt> <var>offset</var>
24*33de042dSApple OSS Distributions<dd>
25*33de042dSApple OSS Distributions[in scalar]
26*33de042dSApple OSS DistributionsThe offset within the memory object, in bytes.
27*33de042dSApple OSS Distributions<p>
28*33de042dSApple OSS Distributions<dt> <var>size</var>
29*33de042dSApple OSS Distributions<dd>
30*33de042dSApple OSS Distributions[in scalar]
31*33de042dSApple OSS DistributionsThe number of bytes of data (starting at <var>offset</var>).  The number
32*33de042dSApple OSS Distributionsmust convert to an integral number of memory object pages.
33*33de042dSApple OSS Distributions</dl>
34*33de042dSApple OSS Distributions<h3>DESCRIPTION</h3>
35*33de042dSApple OSS Distributions<p>
36*33de042dSApple OSS DistributionsThe <strong>memory_object_data_unavailable</strong> function indicates
37*33de042dSApple OSS Distributionsthat the memory
38*33de042dSApple OSS Distributionsmanager cannot provide the kernel with the data requested for
39*33de042dSApple OSS Distributionsthe given region.
40*33de042dSApple OSS DistributionsInstead, the kernel should provide the data for this region.
41*33de042dSApple OSS Distributions<p>
42*33de042dSApple OSS DistributionsA memory manager can use this call in any of the following situations:
43*33de042dSApple OSS Distributions<ul>
44*33de042dSApple OSS Distributions<li>
45*33de042dSApple OSS DistributionsWhen the object was created by the kernel
46*33de042dSApple OSS Distributions(via <strong>memory_object_create</strong>) and
47*33de042dSApple OSS Distributionsthe kernel has not yet provided data for the region (via either
48*33de042dSApple OSS Distributions<strong>memory_object_data_initialize</strong> or <strong>memory_object_data_return</strong>).
49*33de042dSApple OSS DistributionsIn this case, the
50*33de042dSApple OSS Distributionsobject is a temporary memory object; the memory manager is the default
51*33de042dSApple OSS Distributionsmemory manager; and the kernel should provide zero-filled pages for the
52*33de042dSApple OSS Distributionsobject.
53*33de042dSApple OSS Distributions     <p>
54*33de042dSApple OSS Distributions<li>
55*33de042dSApple OSS DistributionsWhen the object is a normal user-created memory object.  In this case, the
56*33de042dSApple OSS Distributionskernel should provide zero-filled pages for the region.
57*33de042dSApple OSS Distributions</ul>
58*33de042dSApple OSS Distributions<h3>RETURN VALUES</h3>
59*33de042dSApple OSS Distributions<p>
60*33de042dSApple OSS DistributionsOnly generic errors apply.
61*33de042dSApple OSS Distributions<h3>RELATED INFORMATION</h3>
62*33de042dSApple OSS Distributions<p>
63*33de042dSApple OSS DistributionsFunctions:
64*33de042dSApple OSS Distributions<a href="memory_object_create.html"><strong>memory_object_create</strong></a>,
65*33de042dSApple OSS Distributions<a href="memory_object_data_error.html"><strong>memory_object_data_error</strong></a>,
66*33de042dSApple OSS Distributions<a href="memory_object_data_request.html"><strong>memory_object_data_request</strong></a>,
67*33de042dSApple OSS Distributions<a href="memory_object_data_supply.html"><strong>memory_object_data_supply</strong></a>.
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