xref: /minix/minix/lib/libsys/sched_start.c (revision 00b67f09)
1 #include "syslib.h"
2 #include <assert.h>
3 #include <machine/archtypes.h>
4 #include <minix/timers.h>
5 #include <minix/sched.h>
6 #include <string.h>
7 
8 /*===========================================================================*
9  *				sched_inherit				     *
10  *===========================================================================*/
11 int sched_inherit(endpoint_t scheduler_e,
12 	endpoint_t schedulee_e, endpoint_t parent_e, unsigned maxprio,
13 	endpoint_t *newscheduler_e)
14 {
15 	int rv;
16 	message m;
17 
18 	assert(_ENDPOINT_P(scheduler_e) >= 0);
19 	assert(_ENDPOINT_P(schedulee_e) >= 0);
20 	assert(_ENDPOINT_P(parent_e) >= 0);
21 	assert(maxprio < NR_SCHED_QUEUES);
22 	assert(newscheduler_e);
23 
24 	memset(&m, 0, sizeof(m));
25 	m.m_lsys_sched_scheduling_start.endpoint	= schedulee_e;
26 	m.m_lsys_sched_scheduling_start.parent		= parent_e;
27 	m.m_lsys_sched_scheduling_start.maxprio		= maxprio;
28 
29 	/* Send the request to the scheduler */
30 	if ((rv = _taskcall(scheduler_e, SCHEDULING_INHERIT, &m))) {
31 		return rv;
32 	}
33 
34 	/* Store the process' scheduler. Note that this might not be the
35 	 * scheduler we sent the SCHEDULING_INHERIT message to. That scheduler
36 	 * might have forwarded the scheduling message on to another scheduler
37 	 * before returning the message.
38 	 */
39 	*newscheduler_e = m.m_sched_lsys_scheduling_start.scheduler;
40 	return (OK);
41 }
42 
43 /*===========================================================================*
44  *				sched_start				     *
45  *===========================================================================*/
46 int sched_start(endpoint_t scheduler_e,
47 			endpoint_t schedulee_e,
48 			endpoint_t parent_e,
49 			int maxprio,
50 			int quantum,
51 			int cpu,
52 			endpoint_t *newscheduler_e)
53 {
54 	int rv;
55 	message m;
56 
57 	/* No scheduler given? We are done. */
58 	if(scheduler_e == NONE) {
59 		return OK;
60 	}
61 
62 	assert(_ENDPOINT_P(schedulee_e) >= 0);
63 	assert(_ENDPOINT_P(parent_e) >= 0);
64 	assert(maxprio >= 0);
65 	assert(maxprio < NR_SCHED_QUEUES);
66 	assert(quantum > 0);
67 	assert(newscheduler_e);
68 
69 	/* The KERNEL must schedule this process. */
70 	if(scheduler_e == KERNEL) {
71 		if ((rv = sys_schedctl(SCHEDCTL_FLAG_KERNEL,
72 			schedulee_e, maxprio, quantum, cpu)) != OK) {
73 			return rv;
74 		}
75 		*newscheduler_e = scheduler_e;
76 		return OK;
77 	}
78 
79 	/* A user-space scheduler must schedule this process. */
80 	memset(&m, 0, sizeof(m));
81 	m.m_lsys_sched_scheduling_start.endpoint	= schedulee_e;
82 	m.m_lsys_sched_scheduling_start.parent		= parent_e;
83 	m.m_lsys_sched_scheduling_start.maxprio		= maxprio;
84 	m.m_lsys_sched_scheduling_start.quantum		= quantum;
85 
86 	/* Send the request to the scheduler */
87 	if ((rv = _taskcall(scheduler_e, SCHEDULING_START, &m))) {
88 		return rv;
89 	}
90 
91 	/* Store the process' scheduler. Note that this might not be the
92 	 * scheduler we sent the SCHEDULING_START message to. That scheduler
93 	 * might have forwarded the scheduling message on to another scheduler
94 	 * before returning the message.
95 	 */
96 	*newscheduler_e = m.m_sched_lsys_scheduling_start.scheduler;
97 	return (OK);
98 }
99