/**
* Change the scheduling priority of a process.
*
* Process piorities are signed ints, whereas a larger integer value means
* higher scheduling priority. The default priority for new processes is 0.
* The idle process runs with the lowest possible priority: INT_MIN.
*
* A process with a higher priority always preempts lower priority processes.
* Processes of equal priority share the CPU time according to a simple
* round-robin policy.
*
* As a general rule to maximize responsiveness, compute-bound processes
* should be assigned negative priorities and tight, interactive processes
* should be assigned positive priorities.
*
* To avoid interfering with system background activities such as input
* processing, application processes should remain within the range -10
* and +10.
*/
void proc_setPri(struct Process *proc, int pri)
{
#if CONFIG_KERN_PRI_INHERIT
int new_pri;
/*
* Whatever it will happen below, this is the new
* original priority of the process, i.e., the priority
* it has without taking inheritance under account.
*/
proc->orig_pri = pri;
/* If not changing anything we can just leave */
if ((new_pri = __prio_proc(proc)) == proc->link.pri)
return;
/*
* Actual process priority is the highest among its
* own priority and the one of the top-priority
* process that it is blocking (returned by
* __prio_proc()).
*/
proc->link.pri = new_pri;
#else
if (proc->link.pri == pri)
return;
proc->link.pri = pri;
#endif // CONFIG_KERN_PRI_INHERIT
if (proc != current_process)
ATOMIC(sched_reenqueue(proc));
}
/**
* Change the scheduling priority of a process.
*
* Process piorities are signed ints, whereas a larger integer value means
* higher scheduling priority. The default priority for new processes is 0.
* The idle process runs with the lowest possible priority: INT_MIN.
*
* A process with a higher priority always preempts lower priority processes.
* Processes of equal priority share the CPU time according to a simple
* round-robin policy.
*
* As a general rule to maximize responsiveness, compute-bound processes
* should be assigned negative priorities and tight, interactive processes
* should be assigned positive priorities.
*
* To avoid interfering with system background activities such as input
* processing, application processes should remain within the range -10
* and +10.
*/
void proc_setPri(struct Process *proc, int pri)
{
if (proc->link.pri == pri)
return;
proc->link.pri = pri;
if (proc != current_process)
ATOMIC(sched_reenqueue(proc));
}
