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author | Alexis211 <alexis211@gmail.com> | 2010-08-10 22:17:24 +0200 |
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committer | Alexis211 <alexis211@gmail.com> | 2010-08-10 22:17:24 +0200 |
commit | a75acb568a301903f00d3230467de2a097cce0db (patch) | |
tree | 27dab61327d56238aafaad3d4a291da422c3bed1 /src/kernel/task/sched.c | |
parent | c7c2e36c2bb2cf7302f60a70e0ede0490f98b05e (diff) | |
download | TCE-a75acb568a301903f00d3230467de2a097cce0db.tar.gz TCE-a75acb568a301903f00d3230467de2a097cce0db.zip |
Added priorities to the scheduler.
Diffstat (limited to 'src/kernel/task/sched.c')
-rw-r--r-- | src/kernel/task/sched.c | 50 |
1 files changed, 37 insertions, 13 deletions
diff --git a/src/kernel/task/sched.c b/src/kernel/task/sched.c index 85329ea..2b0ef8a 100644 --- a/src/kernel/task/sched.c +++ b/src/kernel/task/sched.c @@ -2,25 +2,49 @@ #include <core/sys.h> #include <mem/mem.h> -static struct thread *queue = 0, *last = 0; +// Lower priority numbers have high priority. Priorities must start at 0. +#define PRIORITIES 4 // we have 4 priority levels +#define PRIORITY(t) (t->process->privilege) //get priority for a thread -/* Used by task.c. Enqueus a thread in the queue of threads waiting to run. */ -void sched_enqueue(struct thread *t) { +extern struct thread *idle_thread; + +static struct thread *queue[PRIORITIES] = {0}, *last[PRIORITIES] = {0}; + +/* For internal use only. Enqueues specified thread in specified priority queue. */ +static void sched_enqueueIn(struct thread *t, int qid) { t->queue_next = 0; - if (queue == 0) { - queue = last = t; + if (queue[qid] == 0) { + queue[qid] = last[qid] = t; } else { - last->queue_next = t; - last = t; + last[qid]->queue_next = t; + last[qid] = t; } } -/* Used by task.c. Pops a thread from the queue to be run. */ +/* For internal use only. Pops a thread from specified queue, if available. */ +static struct thread *sched_dequeueFrom(int qid) { + if (queue[qid] == 0) return 0; + struct thread *it = queue[qid]; + ASSERT((it->queue_next == 0 && it == last[qid]) || it != last[qid]); + queue[qid] = it->queue_next; + if (queue[qid] == 0) last[qid] = 0; + return it; +} + +/* Used by task.c. Enqueus a thread in the corresponding priority queue. */ +void sched_enqueue(struct thread *t) { + if (t == idle_thread) return; + sched_enqueueIn(t, PRIORITY(t)); +} + +/* Used by task.c. Pops a thread from the lowest priority non-empty queue. */ struct thread *sched_dequeue() { - if (queue == 0) return 0; - struct thread *it = queue; - ASSERT((it->queue_next == 0 && it == last) || it != last); - queue = it->queue_next; - if (queue == 0) last = 0; + struct thread *it = 0; + int i; + for (i = 0; i < PRIORITIES; i++) { + it = sched_dequeueFrom(i); + if (it != 0) break; + } + if (it == 0) return idle_thread; return it; } |