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32 * $FreeBSD: src/sys/posix4/ksched.c,v 1.7.2.1 2000/05/16 06:58:13 dillon Exp $
36 * ksched: Soft real time scheduling based on "rtprio".
39 #include <sys/param.h>
40 #include <sys/systm.h>
41 #include <sys/malloc.h>
42 #include <sys/posix4.h>
44 #include <sys/kernel.h>
45 #include <sys/resource.h>
46 #include <machine/cpu.h> /* For need_user_resched */
49 /* ksched: Real-time extension to support POSIX priority scheduling.
53 struct timespec rr_interval;
57 ksched_attach(struct ksched **p)
59 struct ksched *ksched;
61 ksched = kmalloc(sizeof(*ksched), M_P31B, M_WAITOK);
63 ksched->rr_interval.tv_sec = 0;
64 ksched->rr_interval.tv_nsec = 1000000000L / 10; /* XXX */
71 ksched_detach(struct ksched *p)
79 * XXX About priorities
81 * POSIX 1003.1b requires that numerically higher priorities be of
82 * higher priority. It also permits sched_setparam to be
83 * implementation defined for SCHED_OTHER. I don't like
84 * the notion of inverted priorites for normal processes when
85 * you can use "setpriority" for that.
87 * I'm rejecting sched_setparam for SCHED_OTHER with EINVAL.
90 /* Macros to convert between the unix (lower numerically is higher priority)
91 * and POSIX 1003.1b (higher numerically is higher priority)
94 #define p4prio_to_rtpprio(P) (RTP_PRIO_MAX - (P))
95 #define rtpprio_to_p4prio(P) (RTP_PRIO_MAX - (P))
98 * These improve readability a bit for me:
100 #define P1B_PRIO_MIN rtpprio_to_p4prio(RTP_PRIO_MAX)
101 #define P1B_PRIO_MAX rtpprio_to_p4prio(RTP_PRIO_MIN)
104 getscheduler(register_t *ret, struct ksched *ksched, struct lwp *lp)
108 switch (lp->lwp_rtprio.type) {
112 case RTP_PRIO_REALTIME:
124 ksched_setparam(register_t *ret, struct ksched *ksched,
125 struct lwp *lp, const struct sched_param *param)
130 e = getscheduler(&policy, ksched, lp);
133 if (policy == SCHED_OTHER)
136 e = ksched_setscheduler(ret, ksched, lp, policy, param);
143 ksched_getparam(register_t *ret, struct ksched *ksched,
144 struct lwp *lp, struct sched_param *param)
146 if (RTP_PRIO_IS_REALTIME(lp->lwp_rtprio.type))
147 param->sched_priority = rtpprio_to_p4prio(lp->lwp_rtprio.prio);
153 * XXX The priority and scheduler modifications should
154 * be moved into published interfaces in kern/kern_sync.
156 * The permissions to modify process p were checked in "p31b_proc()".
160 ksched_setscheduler(register_t *ret, struct ksched *ksched,
161 struct lwp *lp, int policy, const struct sched_param *param)
169 if (param->sched_priority >= P1B_PRIO_MIN &&
170 param->sched_priority <= P1B_PRIO_MAX) {
171 rtp.prio = p4prio_to_rtpprio(param->sched_priority);
172 rtp.type = (policy == SCHED_FIFO) ?
173 RTP_PRIO_FIFO : RTP_PRIO_REALTIME;
175 lp->lwp_rtprio = rtp;
182 rtp.type = RTP_PRIO_NORMAL;
183 rtp.prio = p4prio_to_rtpprio(param->sched_priority);
184 lp->lwp_rtprio = rtp;
187 * XXX Simply revert to whatever we had for last
188 * normal scheduler priorities.
189 * This puts a requirement
190 * on the scheduling code: You must leave the
191 * scheduling info alone.
201 ksched_getscheduler(register_t *ret, struct ksched *ksched, struct lwp *lp)
203 return getscheduler(ret, ksched, lp);
207 * ksched_yield: Yield the CPU.
212 ksched_yield(register_t *ret, struct ksched *ksched)
216 if ((lp = curthread->td_lwp) != NULL)
217 lp->lwp_proc->p_usched->yield(lp);
225 ksched_get_priority_max(register_t*ret, struct ksched *ksched, int policy)
249 ksched_get_priority_min(register_t *ret, struct ksched *ksched, int policy)
272 ksched_rr_get_interval(register_t *ret, struct ksched *ksched,
273 struct lwp *lp, struct timespec *timespec)
275 *timespec = ksched->rr_interval;