Add LITMUS^RT core implementation

This patch adds the core of LITMUS^RT:

 - library functionality (heaps, rt_domain, prioritization, etc.)
 - budget enforcement logic
 - job management
 - system call backends
 - virtual devices (control page, etc.)
 - scheduler plugin API (and dummy plugin)

This code compiles, but is not yet integrated with the rest of Linux.

1 files changed, 55 insertions, 0 deletions

diff --git a/litmus/jobs.c b/litmus/jobs.c
new file mode 100644
index 000000000000..89a0810415fa
--- /dev/null
+++ b/litmus/jobs.c
@@ -0,0 +1,55 @@
+/* litmus/jobs.c - common job control code
+ */
+
+#include <linux/sched.h>
+
+#include <litmus/litmus.h>
+#include <litmus/jobs.h>
+
+static inline void setup_release(struct task_struct *t, lt_t release)
+{
+        /* prepare next release */
+        t->rt_param.job_params.release = release;
+        t->rt_param.job_params.deadline = release + get_rt_relative_deadline(t);
+        t->rt_param.job_params.exec_time = 0;
+
+        /* update job sequence number */
+        t->rt_param.job_params.job_no++;
+}
+
+void prepare_for_next_period(struct task_struct *t)
+{
+        BUG_ON(!t);
+
+        /* Record lateness before we set up the next job's
+         * release and deadline. Lateness may be negative.
+         */
+        t->rt_param.job_params.lateness =
+                (long long)litmus_clock() -
+                (long long)t->rt_param.job_params.deadline;
+
+        setup_release(t, get_release(t) + get_rt_period(t));
+        tsk_rt(t)->dont_requeue = 0;
+}
+
+void release_at(struct task_struct *t, lt_t start)
+{
+        BUG_ON(!t);
+        setup_release(t, start);
+        tsk_rt(t)->completed = 0;
+}
+
+
+/*
+ *      Deactivate current task until the beginning of the next period.
+ */
+long complete_job(void)
+{
+        /* Mark that we do not excute anymore */
+        tsk_rt(current)->completed = 1;
+        /* call schedule, this will return when a new job arrives
+         * it also takes care of preparing for the next release
+         */
+        schedule();
+        return 0;
+}