1*0f4c859eSApple OSS Distributions<h2>vm_behavior_set</h2> 2*0f4c859eSApple OSS Distributions<hr> 3*0f4c859eSApple OSS Distributions<p> 4*0f4c859eSApple OSS Distributions<strong>Function</strong> - Specify expected access patterns for the target VM region. 5*0f4c859eSApple OSS Distributions<h3>SYNOPSIS</h3> 6*0f4c859eSApple OSS Distributions<pre> 7*0f4c859eSApple OSS Distributions<strong>kern_return_t vm_behavior_set</strong> 8*0f4c859eSApple OSS Distributions <strong>(vm_task_t</strong> <var>target_task</var>, 9*0f4c859eSApple OSS Distributions <strong>vm_address_t</strong> <var>address</var>, 10*0f4c859eSApple OSS Distributions <strong>vm_size_t</strong> <var>size</var>, 11*0f4c859eSApple OSS Distributions <strong>vm_behavior_t</strong> <var>behavior</var><strong>);</strong> 12*0f4c859eSApple OSS Distributions</pre> 13*0f4c859eSApple OSS Distributions<h3>PARAMETERS</h3> 14*0f4c859eSApple OSS Distributions<dl> 15*0f4c859eSApple OSS Distributions<p> 16*0f4c859eSApple OSS Distributions<dt> <var>target_task</var> 17*0f4c859eSApple OSS Distributions<dd> 18*0f4c859eSApple OSS Distributions[in task send right] 19*0f4c859eSApple OSS DistributionsThe port for the task in whose address space the 20*0f4c859eSApple OSS Distributionsmemory object behavior is to be set. 21*0f4c859eSApple OSS Distributions<p> 22*0f4c859eSApple OSS Distributions<dt> <var>address</var> 23*0f4c859eSApple OSS Distributions<dd> 24*0f4c859eSApple OSS Distributions[in scalar] 25*0f4c859eSApple OSS DistributionsThe starting address for the memory region. 26*0f4c859eSApple OSS Distributions<p> 27*0f4c859eSApple OSS Distributions<dt> <var>size</var> 28*0f4c859eSApple OSS Distributions<dd> 29*0f4c859eSApple OSS Distributions[in scalar] 30*0f4c859eSApple OSS DistributionsThe number of bytes in the region. 31*0f4c859eSApple OSS Distributions<p> 32*0f4c859eSApple OSS Distributions<dt> <var>behavior</var> 33*0f4c859eSApple OSS Distributions<dd> 34*0f4c859eSApple OSS Distributions[in scalar] 35*0f4c859eSApple OSS DistributionsThe expected reference pattern for the memory. Possible 36*0f4c859eSApple OSS Distributionsvalues are: 37*0f4c859eSApple OSS Distributions<dl> 38*0f4c859eSApple OSS Distributions<p> 39*0f4c859eSApple OSS Distributions<dt> <strong>VM_BEHAVIOR_DEFAULT</strong> 40*0f4c859eSApple OSS Distributions<dd> 41*0f4c859eSApple OSS DistributionsThe system's default behavior. Assumes strong locality of 42*0f4c859eSApple OSS Distributionsreference, so LRU page replacement, possibly with pre-fetch, 43*0f4c859eSApple OSS Distributionswould be appropriate. 44*0f4c859eSApple OSS Distributions<p> 45*0f4c859eSApple OSS Distributions<dt> <strong>VM_BEHAVIOR_RANDOM</strong> 46*0f4c859eSApple OSS Distributions<dd> 47*0f4c859eSApple OSS DistributionsNo particular order expected. Assumes weak locality of 48*0f4c859eSApple OSS Distributionsreference, so LRU page replacement may be ineffective. 49*0f4c859eSApple OSS Distributions<p> 50*0f4c859eSApple OSS Distributions<dt> <strong>VM_BEHAVIOR_SEQUENTIAL</strong> 51*0f4c859eSApple OSS Distributions<dd> 52*0f4c859eSApple OSS DistributionsForward sequential order. 53*0f4c859eSApple OSS Distributions<p> 54*0f4c859eSApple OSS Distributions<dt> <strong>VM_BEHAVIOR_RSEQNTL</strong> 55*0f4c859eSApple OSS Distributions<dd> 56*0f4c859eSApple OSS DistributionsReverse sequential order. 57*0f4c859eSApple OSS Distributions</dl> 58*0f4c859eSApple OSS Distributions</dl> 59*0f4c859eSApple OSS Distributions<h3>DESCRIPTION</h3> 60*0f4c859eSApple OSS Distributions<p> 61*0f4c859eSApple OSS DistributionsThe <strong>vm_behavior_set</strong> function informs the kernel of 62*0f4c859eSApple OSS Distributionsthe expected access 63*0f4c859eSApple OSS Distributionspattern for a region of memory. The kernel uses this information 64*0f4c859eSApple OSS Distributionsto bias its prefetch and page 65*0f4c859eSApple OSS Distributionsreplacement algorithms. 66*0f4c859eSApple OSS Distributions<p> 67*0f4c859eSApple OSS DistributionsThe region starts at the beginning of the virtual page containing 68*0f4c859eSApple OSS Distributions<var>address</var>; it ends at the end of the virtual page containing 69*0f4c859eSApple OSS Distributions<var>address</var> + <var>size</var> - 1. Because of this 70*0f4c859eSApple OSS Distributionsrounding to virtual page boundaries, the amount of memory affected may be 71*0f4c859eSApple OSS Distributionsgreater than <var>size</var>. Use <strong>host_page_size</strong> 72*0f4c859eSApple OSS Distributionsto find the current virtual page size. 73*0f4c859eSApple OSS Distributions<h3>NOTES</h3> 74*0f4c859eSApple OSS Distributions<p> 75*0f4c859eSApple OSS DistributionsThis interface is machine word length specific because of the virtual address 76*0f4c859eSApple OSS Distributionsparameter. 77*0f4c859eSApple OSS Distributions<h3>RETURN VALUES</h3> 78*0f4c859eSApple OSS Distributions<dl> 79*0f4c859eSApple OSS Distributions<p> 80*0f4c859eSApple OSS Distributions<dt> <strong>KERN_INVALID_ADDRESS</strong> 81*0f4c859eSApple OSS Distributions<dd> 82*0f4c859eSApple OSS DistributionsThe specified address is illegal or reserved. 83*0f4c859eSApple OSS Distributions</dl> 84*0f4c859eSApple OSS Distributions<h3>RELATED INFORMATION</h3> 85*0f4c859eSApple OSS Distributions<p> 86*0f4c859eSApple OSS DistributionsFunctions: 87*0f4c859eSApple OSS Distributions<a href="vm_region.html"><strong>vm_region</strong></a>, 88*0f4c859eSApple OSS Distributions<a href="host_page_size.html"><strong>host_page_size</strong></a>. 89