xref: /xnu-10002.1.13/osfmk/man/default_pager_add_segment.html (revision 1031c584a5e37aff177559b9f69dbd3c8c3fd30a)
1*1031c584SApple OSS Distributions<h2>default_pager_add_segment</h2>
2*1031c584SApple OSS Distributions<hr>
3*1031c584SApple OSS Distributions<p>
4*1031c584SApple OSS Distributions<strong>Server Interface</strong> - Add additional backing storage for a default pager.
5*1031c584SApple OSS Distributions<h3>SYNOPSIS</h3>
6*1031c584SApple OSS Distributions<pre>
7*1031c584SApple OSS Distributions<strong>#include&lt mach/default_pager_object.h&gt</strong>
8*1031c584SApple OSS Distributions
9*1031c584SApple OSS Distributions<strong>kern_return_t   default_pager_add_segment</strong>
10*1031c584SApple OSS Distributions                <strong>(mach_port_t</strong>                      <var>backing_store</var>,
11*1031c584SApple OSS Distributions                 <strong>mach_port_t</strong>                             <var>device</var>,
12*1031c584SApple OSS Distributions                 <strong>recnum_t</strong>                                <var>offset</var>,
13*1031c584SApple OSS Distributions                 <strong>recnum_t</strong>                                 <var>count</var>,
14*1031c584SApple OSS Distributions                 <strong>int</strong>                                <var>record_size</var><strong>);</strong>
15*1031c584SApple OSS Distributions</pre>
16*1031c584SApple OSS Distributions<h3>PARAMETERS</h3>
17*1031c584SApple OSS Distributions<dl>
18*1031c584SApple OSS Distributions<p>
19*1031c584SApple OSS Distributions<dt> <var>backing_store</var>
20*1031c584SApple OSS Distributions<dd>
21*1031c584SApple OSS Distributions[in backing store (receive) right] The backing store port.
22*1031c584SApple OSS Distributions<p>
23*1031c584SApple OSS Distributions<dt> <var>device</var>
24*1031c584SApple OSS Distributions<dd>
25*1031c584SApple OSS Distributions[in device port] The port for the device containing the backing storage
26*1031c584SApple OSS Distributionspartition.
27*1031c584SApple OSS Distributions<p>
28*1031c584SApple OSS Distributions<dt> <var>offset</var>
29*1031c584SApple OSS Distributions<dd>
30*1031c584SApple OSS Distributions[in scalar] The offset, in <var>record_size units</var>, to the beginning of the
31*1031c584SApple OSS Distributionsbacking storage on the device.
32*1031c584SApple OSS Distributions<p>
33*1031c584SApple OSS Distributions<dt> <var>count</var>
34*1031c584SApple OSS Distributions<dd>
35*1031c584SApple OSS Distributions[in scalar] The number of <var>record_size</var> units
36*1031c584SApple OSS Distributionsin the partition/segment.
37*1031c584SApple OSS Distributions<p>
38*1031c584SApple OSS Distributions<dt> <var>record_size</var>
39*1031c584SApple OSS Distributions<dd>
40*1031c584SApple OSS Distributions[in scalar] The size, in bytes, of the storage device record.
41*1031c584SApple OSS Distributions</dl>
42*1031c584SApple OSS Distributions<h3>DESCRIPTION</h3>
43*1031c584SApple OSS Distributions<p>
44*1031c584SApple OSS DistributionsThe <strong>default_pager_add_segment</strong> function is called to add a partition to
45*1031c584SApple OSS Distributionsa default pager's backing storage (i.e. expand the amount of backing
46*1031c584SApple OSS Distributionsstorage available to a memory manager). The kernel does not make
47*1031c584SApple OSS Distributionsthis call itself (which is why it can be a synchronous call); this
48*1031c584SApple OSS Distributionsrequest is only issued by tasks holding the backing store port,
49*1031c584SApple OSS Distributionscreated with <strong>default_pager_backing_store_create</strong>, for a default memory
50*1031c584SApple OSS Distributionsmanager.
51*1031c584SApple OSS DistributionsThe result is that the pager may use count records on device starting
52*1031c584SApple OSS Distributionsat offset for paging, and each record is record_size bytes in length
53*1031c584SApple OSS Distributions(note that the device_* calls are, or can be, record oriented).
54*1031c584SApple OSS Distributions<h3>RETURN VALUES</h3>
55*1031c584SApple OSS Distributions<dl>
56*1031c584SApple OSS Distributions<p>
57*1031c584SApple OSS Distributions<dt> <strong>KERN_FAILURE</strong>
58*1031c584SApple OSS Distributions<dd>
59*1031c584SApple OSS DistributionsThe default pager does not support this operation.
60*1031c584SApple OSS Distributions<p>
61*1031c584SApple OSS Distributions<dt> <strong>KERN_INVALID_ARGUMENT</strong>
62*1031c584SApple OSS Distributions<dd>
63*1031c584SApple OSS DistributionsThe <var>backing_store</var> port does not represent a valid backing store or the
64*1031c584SApple OSS Distributionsspecified segment overlaps an existing partition.
65*1031c584SApple OSS Distributions<p>
66*1031c584SApple OSS Distributions<dt> <strong>KERN_RESOURCE_SHORTAGE</strong>
67*1031c584SApple OSS Distributions<dd>
68*1031c584SApple OSS DistributionsThe default pager is unable to allocate internal resources
69*1031c584SApple OSS Distributions     to manage the new backing storage.
70*1031c584SApple OSS Distributions<p>
71*1031c584SApple OSS Distributions<dt> <strong>KERN_SUCCESS</strong>
72*1031c584SApple OSS Distributions<dd>
73*1031c584SApple OSS DistributionsThe operation was successful.
74*1031c584SApple OSS Distributions</dl>
75*1031c584SApple OSS Distributions<h3>RELATED INFORMATION</h3>
76*1031c584SApple OSS Distributions<p>
77*1031c584SApple OSS DistributionsFunctions:
78*1031c584SApple OSS Distributions<a href="DP_backing_store_create.html"><strong>default_pager_backing_store_create</strong></a>,
79*1031c584SApple OSS Distributions<a href="DP_backing_store_delete.html"><strong>default_pager_backing_store_delete</strong></a>,
80*1031c584SApple OSS Distributions<a href="DP_backing_store_info.html"><strong>default_pager_backing_store_info</strong></a>.
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