xref: /xnu-11417.121.6/osfmk/man/memory_object_data_error.html (revision a1e26a70f38d1d7daa7b49b258e2f8538ad81650)
1*a1e26a70SApple OSS Distributions<h2>memory_object_data_error</h2>
2*a1e26a70SApple OSS Distributions<hr>
3*a1e26a70SApple OSS Distributions<p>
4*a1e26a70SApple OSS Distributions<strong>Function</strong> - An error prevents the supply of previously requested data.
5*a1e26a70SApple OSS Distributions<h3>SYNOPSIS</h3>
6*a1e26a70SApple OSS Distributions<pre>
7*a1e26a70SApple OSS Distributions<strong>kern_return_t   memory_object_data_error</strong>
8*a1e26a70SApple OSS Distributions                <strong>(memory_object_control_t</strong>         <var>memory_control</var>,
9*a1e26a70SApple OSS Distributions                 <strong>vm_offset_t</strong>                             <var>offset</var>,
10*a1e26a70SApple OSS Distributions                 <strong>vm_size_t</strong>                                 <var>size</var>,
11*a1e26a70SApple OSS Distributions                 <strong>kern_return_t</strong>                           <var>reason</var><strong>);</strong>
12*a1e26a70SApple OSS Distributions</pre>
13*a1e26a70SApple OSS Distributions<h3>PARAMETERS</h3>
14*a1e26a70SApple OSS Distributions<dl>
15*a1e26a70SApple OSS Distributions<p>
16*a1e26a70SApple OSS Distributions<dt> <var>memory_control</var>
17*a1e26a70SApple OSS Distributions<dd>
18*a1e26a70SApple OSS Distributions[in memory-cache-control send right]
19*a1e26a70SApple OSS DistributionsThe memory cache control port
20*a1e26a70SApple OSS Distributionsto be used by the memory manager for cache management requests.
21*a1e26a70SApple OSS DistributionsThis port is provided by the kernel in a <strong>memory_object_create</strong> call.
22*a1e26a70SApple OSS Distributions<p>
23*a1e26a70SApple OSS Distributions<dt> <var>offset</var>
24*a1e26a70SApple OSS Distributions<dd>
25*a1e26a70SApple OSS Distributions[in scalar]
26*a1e26a70SApple OSS DistributionsThe offset within the memory object, in bytes.
27*a1e26a70SApple OSS Distributions<p>
28*a1e26a70SApple OSS Distributions<dt> <var>size</var>
29*a1e26a70SApple OSS Distributions<dd>
30*a1e26a70SApple OSS Distributions[in scalar]
31*a1e26a70SApple OSS DistributionsThe number of bytes of data (starting at <var>offset</var>).  The number
32*a1e26a70SApple OSS Distributionsmust convert to an integral number of memory object pages.
33*a1e26a70SApple OSS Distributions<p>
34*a1e26a70SApple OSS Distributions<dt> <var>reason</var>
35*a1e26a70SApple OSS Distributions<dd>
36*a1e26a70SApple OSS Distributions[in scalar]
37*a1e26a70SApple OSS DistributionsReason for the error.
38*a1e26a70SApple OSS Distributions</dl>
39*a1e26a70SApple OSS Distributions<h3>DESCRIPTION</h3>
40*a1e26a70SApple OSS Distributions<p>
41*a1e26a70SApple OSS DistributionsThe <strong>memory_object_data_error</strong> function indicates that
42*a1e26a70SApple OSS Distributionsthe memory manager
43*a1e26a70SApple OSS Distributionscannot provide the kernel with the data requested for the given region,
44*a1e26a70SApple OSS Distributionsspecifying a reason for the error.
45*a1e26a70SApple OSS Distributions<p>
46*a1e26a70SApple OSS DistributionsWhen the kernel issues a <strong>memory_object_data_request</strong> call, the memory
47*a1e26a70SApple OSS Distributionsmanager can respond with a <strong>memory_object_data_error</strong>
48*a1e26a70SApple OSS Distributionscall to indicate that the
49*a1e26a70SApple OSS Distributionspage cannot be retrieved, and that a memory failure exception should be raised
50*a1e26a70SApple OSS Distributionsin any client threads that are waiting for the page.  Clients
51*a1e26a70SApple OSS Distributionsare permitted to catch
52*a1e26a70SApple OSS Distributionsthese exceptions and retry their page faults.  As a result, this
53*a1e26a70SApple OSS Distributionscall can be used to
54*a1e26a70SApple OSS Distributionsreport transient errors as well as permanent ones.  A memory manager can use
55*a1e26a70SApple OSS Distributionsthis call for both hardware errors (for example, disk failures) and software
56*a1e26a70SApple OSS Distributionserrors (for example, accessing data that does not exist or is protected).
57*a1e26a70SApple OSS Distributions<h3>NOTES</h3>
58*a1e26a70SApple OSS Distributions<p>
59*a1e26a70SApple OSS DistributionsIf reason has a system code of <var>err_kern</var>, the kernel will substitute
60*a1e26a70SApple OSS Distributionsan error value
61*a1e26a70SApple OSS Distributionsof <strong>KERN_MEMORY_ERROR</strong>.
62*a1e26a70SApple OSS Distributions<h3>RETURN VALUES</h3>
63*a1e26a70SApple OSS Distributions<p>
64*a1e26a70SApple OSS DistributionsOnly generic errors apply.
65*a1e26a70SApple OSS Distributions<h3>RELATED INFORMATION</h3>
66*a1e26a70SApple OSS Distributions<p>
67*a1e26a70SApple OSS DistributionsFunctions:
68*a1e26a70SApple OSS Distributions<a href="memory_object_data_request.html"><strong>memory_object_data_request</strong></a>,
69*a1e26a70SApple OSS Distributions<a href="memory_object_data_supply.html"><strong>memory_object_data_supply</strong></a>,
70*a1e26a70SApple OSS Distributions<a href="MO_data_unavailable.html"><strong>memory_object_data_unavailable</strong></a>.
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