From 755378a47192a3d1f7c3a8ca6c15c1cf76de0af2 Mon Sep 17 00:00:00 2001 From: Harald Gustafsson Date: Thu, 7 Nov 2013 14:43:40 +0100 Subject: sched/deadline: Add period support for SCHED_DEADLINE tasks Make it possible to specify a period (different or equal than deadline) for -deadline tasks. Relative deadlines (D_i) are used on task arrivals to generate new scheduling (absolute) deadlines as "d = t + D_i", and periods (P_i) to postpone the scheduling deadlines as "d = d + P_i" when the budget is zero. This is in general useful to model (and schedule) tasks that have slow activation rates (long periods), but have to be scheduled soon once activated (short deadlines). Signed-off-by: Harald Gustafsson Signed-off-by: Dario Faggioli Signed-off-by: Juri Lelli Signed-off-by: Peter Zijlstra Link: http://lkml.kernel.org/r/1383831828-15501-7-git-send-email-juri.lelli@gmail.com Signed-off-by: Ingo Molnar --- kernel/sched/core.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) (limited to 'kernel/sched/core.c') diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 548cc04aee45..069230b5c3fb 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -1723,6 +1723,7 @@ static void __sched_fork(unsigned long clone_flags, struct task_struct *p) hrtimer_init(&p->dl.dl_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); p->dl.dl_runtime = p->dl.runtime = 0; p->dl.dl_deadline = p->dl.deadline = 0; + p->dl.dl_period = 0; p->dl.flags = 0; INIT_LIST_HEAD(&p->rt.run_list); @@ -3026,6 +3027,7 @@ __setparam_dl(struct task_struct *p, const struct sched_attr *attr) init_dl_task_timer(dl_se); dl_se->dl_runtime = attr->sched_runtime; dl_se->dl_deadline = attr->sched_deadline; + dl_se->dl_period = attr->sched_period ?: dl_se->dl_deadline; dl_se->flags = attr->sched_flags; dl_se->dl_throttled = 0; dl_se->dl_new = 1; @@ -3067,19 +3069,23 @@ __getparam_dl(struct task_struct *p, struct sched_attr *attr) attr->sched_priority = p->rt_priority; attr->sched_runtime = dl_se->dl_runtime; attr->sched_deadline = dl_se->dl_deadline; + attr->sched_period = dl_se->dl_period; attr->sched_flags = dl_se->flags; } /* * This function validates the new parameters of a -deadline task. * We ask for the deadline not being zero, and greater or equal - * than the runtime. + * than the runtime, as well as the period of being zero or + * greater than deadline. */ static bool __checkparam_dl(const struct sched_attr *attr) { return attr && attr->sched_deadline != 0 && - (s64)(attr->sched_deadline - attr->sched_runtime) >= 0; + (attr->sched_period == 0 || + (s64)(attr->sched_period - attr->sched_deadline) >= 0) && + (s64)(attr->sched_deadline - attr->sched_runtime ) >= 0; } /* -- cgit v1.2.3