osfmk/man/task_policy.html

   1 <h2>task_policy</h2>
<hr>
<p>
<strong>Function</strong> - Set target task's default scheduling policy state.
<h3>SYNOPSIS</h3>
<pre>
<strong>kern_return_t   task_policy</strong>
                <strong>(task_t</strong>                                    <var>task</var>,
                 <strong>policy_t</strong>                                <var>policy</var>,
                 <strong>policy_base_t</strong>                             <var>base</var>,
                 <strong>base</strong>                                <var>base_count</var>,
                 <strong>boolean_t</strong>                            <var>set_limit</var>,
                 <strong>boolean_t</strong>                       <var>change_threads</var><strong>);</strong>
</pre>
<h3>PARAMETERS</h3>
<dl>
<dt> <var>task</var> 
<dd>
[in task send right]
The port for the task whose scheduling attributes 
are to be set.
<dt> <var>policy</var> 
<dd>
[in scalar]
Default policy.  The values currently defined are <strong>POLICY_TIMESHARE</strong>, 
<strong>POLICY_RR</strong> (round robin) and <strong>POLICY_FIFO</strong> (firstin, first-out).
<dt> <var>base</var> 
<dd>
[pointer to in structure]
Base scheduling policy data, <strong>policy_fifo_base</strong>, 
<strong>policy_rr_base</strong> or <strong>policy_timeshare_base</strong>.
<dt> <var>base_count</var> 
<dd>
[in scalar]
The size of the buffer (in natural-sized units).
<dt> <var>set_limit</var> 
<dd>
[in scalar]
True if the scheduling limits for the task should be restricted 
to allow no more service than specified by <var>base</var>.
<dt> <var>change_threads</var> 
<dd>
[in scalar]
True if the attributes (and limits, if <var>set_limit</var> is true) of
existing threads within the task should also be changed.
</dl>
<h3>DESCRIPTION</h3>
<p>
The <strong>task_policy</strong> function sets the default scheduling
attributes for <var>task</var>.  These 
attributes are used when creating new threads.  Changing the default attributes 
for a task does not affect the attributes of the contained threads unless 
<var>change_threads</var> is <strong>TRUE</strong>.  At no time will a thread ever have 
scheduling attributes that exceed the thread's limits.
<h3>RETURN VALUES</h3>
<dl>
<dt> <strong>KERN_INVALID_POLICY</strong>
<dd>
The processor set does not currently enable <var>policy</var>.
<dt> <strong>KERN_POLICY_LIMIT</strong>
<dd>
The specified scheduling attributes exceeds the thread's limits.
</dl>
<h3>RELATED INFORMATION</h3>
<p>
Functions:
<a href="thread_policy.html"><strong>thread_policy</strong></a>,
<a href="thread_set_policy.html"><strong>thread_set_policy</strong></a>,
<a href="task_set_policy.html"><strong>task_set_policy</strong></a>,
<a href="P_set_policy_control.html"><strong>processor_set_policy_control</strong></a>.
<p>
Data Structures:
<a href="policy_fifo_info.html"><strong>policy_fifo_info</strong></a>,
<a href="policy_rr_info.html"><strong>policy_rr_info</strong></a>,
<a href="policy_timeshare_info.html"><strong>policy_timeshare_info</strong></a>.