xref: /xnu-10002.61.3/osfmk/man/memory_object_perf_info.html (revision 0f4c859e951fba394238ab619495c4e1d54d0f34)
1*0f4c859eSApple OSS Distributions<h2>memory_object_perf_info</h2>
2*0f4c859eSApple OSS Distributions<hr>
3*0f4c859eSApple OSS Distributions<p>
4*0f4c859eSApple OSS Distributions<strong>Structure</strong> - Specifies a memory object's attributes with respect to performance.
5*0f4c859eSApple OSS Distributions<h3>SYNOPSIS</h3>
6*0f4c859eSApple OSS Distributions<pre>
7*0f4c859eSApple OSS Distributions<strong>struct  memory_object_perf_info</strong>
8*0f4c859eSApple OSS Distributions<strong>{</strong>
9*0f4c859eSApple OSS Distributions        <strong>vm_offset_t</strong>      <var>cluster_size</var><strong>;</strong>
10*0f4c859eSApple OSS Distributions        <strong>boolean_t</strong>    <var>may_cache_object</var><strong>;</strong>
11*0f4c859eSApple OSS Distributions<strong>};</strong>
12*0f4c859eSApple OSS Distributions
13*0f4c859eSApple OSS Distributions<strong>typedef struct memory_object_perf_info* memory_object_perf_info_t;</strong>
14*0f4c859eSApple OSS Distributions</pre>
15*0f4c859eSApple OSS Distributions<h3>FIELDS</h3>
16*0f4c859eSApple OSS Distributions<dl>
17*0f4c859eSApple OSS Distributions<dt> <var>cluster_size</var>
18*0f4c859eSApple OSS Distributions<dd>
19*0f4c859eSApple OSS DistributionsPreferred cluster size (in bytes) for the memory object.  This helps to
20*0f4c859eSApple OSS Distributionsdetermine how many pages are transferred in individual data request
21*0f4c859eSApple OSS Distributionsand return messages.
22*0f4c859eSApple OSS Distributions<p>
23*0f4c859eSApple OSS Distributions<dt> <var>may_cache_object</var>
24*0f4c859eSApple OSS Distributions<dd>
25*0f4c859eSApple OSS DistributionsCache indicator.  If true, the kernel can cache data associated with the
26*0f4c859eSApple OSS Distributionsmemory object (keep the memory object active) even if no virtual
27*0f4c859eSApple OSS Distributionsmemory references to it remain.
28*0f4c859eSApple OSS Distributions</dl>
29*0f4c859eSApple OSS Distributions<h3>DESCRIPTION</h3>
30*0f4c859eSApple OSS Distributions<p>
31*0f4c859eSApple OSS DistributionsThe <strong>memory_object_perf_info</strong> structure
32*0f4c859eSApple OSS Distributionsdefines a memory object's character with respect to performance.
33*0f4c859eSApple OSS Distributions<h3>NOTES</h3>
34*0f4c859eSApple OSS Distributions<p>
35*0f4c859eSApple OSS DistributionsSharing cached data among all the clients of a memory object can have a major
36*0f4c859eSApple OSS Distributionsimpact on performance, especially if it can be extended across successive, as
37*0f4c859eSApple OSS Distributionswell as concurrent, uses.  For example, the memory objects that represent
38*0f4c859eSApple OSS Distributionsprogram images can be used regularly by different programs.
39*0f4c859eSApple OSS DistributionsBy retaining the data
40*0f4c859eSApple OSS Distributionsfor these memory objects in cache, the number of secondary storage accesses
41*0f4c859eSApple OSS Distributionscan be reduced significantly.
42*0f4c859eSApple OSS Distributions<h3>RELATED INFORMATION</h3>
43*0f4c859eSApple OSS Distributions<p>
44*0f4c859eSApple OSS DistributionsFunctions:
45*0f4c859eSApple OSS Distributions<a href="MO_get_attributes.html"><strong>memory_object_get_attributes</strong></a>,
46*0f4c859eSApple OSS Distributions<a href="MO_change_attributes.html"><strong>memory_object_change_attributes</strong></a>,
47*0f4c859eSApple OSS Distributions<a href="vm_region.html"><strong>vm_region</strong></a>,
48*0f4c859eSApple OSS Distributions<a href="memory_object_synchronize.html"><strong>memory_object_synchronize</strong></a>,
49*0f4c859eSApple OSS Distributions<a href="VSD_memory_manager.html"><strong>vm_set_default_memory_manager</strong></a>,
50*0f4c859eSApple OSS Distributions<a href="vm_msync.html"><strong>vm_msync</strong></a>.
51*0f4c859eSApple OSS Distributions<p>
52*0f4c859eSApple OSS DistributionsStructures:
53*0f4c859eSApple OSS Distributions<a href="memory_object_attr_info.html"><strong>memory_object_attr_info</strong></a>.
54