[ported from 2008.3] Core LITMUS^RT infrastructure

Port 2008.3 Core LITMUS^RT infrastructure to Linux 2.6.32

litmus_sched_class implements 4 new methods:

- prio_changed:
  void

- switched_to:
  void

- get_rr_interval:
  return infinity (i.e., 0)

- select_task_rq:
  return current cpu

1 files changed, 159 insertions, 0 deletions

diff --git a/include/litmus/sched_plugin.h b/include/litmus/sched_plugin.h
new file mode 100644
index 000000000000..94952f6ccbfa
--- /dev/null
+++ b/include/litmus/sched_plugin.h
@@ -0,0 +1,159 @@
+/*
+ * Definition of the scheduler plugin interface.
+ *
+ */
+#ifndef _LINUX_SCHED_PLUGIN_H_
+#define _LINUX_SCHED_PLUGIN_H_
+
+#include <linux/sched.h>
+
+/* struct for semaphore with priority inheritance */
+struct pi_semaphore {
+        atomic_t count;
+        int sleepers;
+        wait_queue_head_t wait;
+        union {
+                /* highest-prio holder/waiter */
+                struct task_struct *task;
+                struct task_struct* cpu_task[NR_CPUS];
+        } hp;
+        /* current lock holder */
+        struct task_struct *holder;
+};
+
+/************************ setup/tear down ********************/
+
+typedef long (*activate_plugin_t) (void);
+typedef long (*deactivate_plugin_t) (void);
+
+
+
+/********************* scheduler invocation ******************/
+
+/*  Plugin-specific realtime tick handler */
+typedef void (*scheduler_tick_t) (struct task_struct *cur);
+/* Novell make sched decision function */
+typedef struct task_struct* (*schedule_t)(struct task_struct * prev);
+/* Clean up after the task switch has occured.
+ * This function is called after every (even non-rt) task switch.
+ */
+typedef void (*finish_switch_t)(struct task_struct *prev);
+
+
+/********************* task state changes ********************/
+
+/* Called to setup a new real-time task.
+ * Release the first job, enqueue, etc.
+ * Task may already be running.
+ */
+typedef void (*task_new_t) (struct task_struct *task,
+                            int on_rq,
+                            int running);
+
+/* Called to re-introduce a task after blocking.
+ * Can potentially be called multiple times.
+ */
+typedef void (*task_wake_up_t) (struct task_struct *task);
+/* called to notify the plugin of a blocking real-time task
+ * it will only be called for real-time tasks and before schedule is called */
+typedef void (*task_block_t)  (struct task_struct *task);
+/* Called when a real-time task exits or changes to a different scheduling
+ * class.
+ * Free any allocated resources
+ */
+typedef void (*task_exit_t)    (struct task_struct *);
+
+/* Called when the new_owner is released from the wait queue
+ * it should now inherit the priority from sem, _before_ it gets readded
+ * to any queue
+ */
+typedef long (*inherit_priority_t) (struct pi_semaphore *sem,
+                                    struct task_struct *new_owner);
+
+/* Called when the current task releases a semahpore where it might have
+ * inherited a piority from
+ */
+typedef long (*return_priority_t) (struct pi_semaphore *sem);
+
+/* Called when a task tries to acquire a semaphore and fails. Check if its
+ * priority is higher than that of the current holder.
+ */
+typedef long (*pi_block_t) (struct pi_semaphore *sem, struct task_struct *t);
+
+
+
+
+/********************* sys call backends  ********************/
+/* This function causes the caller to sleep until the next release */
+typedef long (*complete_job_t) (void);
+
+typedef long (*admit_task_t)(struct task_struct* tsk);
+
+typedef void (*release_at_t)(struct task_struct *t, lt_t start);
+
+struct sched_plugin {
+        struct list_head        list;
+        /*      basic info              */
+        char                    *plugin_name;
+
+        /*      setup                   */
+        activate_plugin_t       activate_plugin;
+        deactivate_plugin_t     deactivate_plugin;
+
+#ifdef CONFIG_SRP
+        unsigned int            srp_active;
+#endif
+
+        /*      scheduler invocation    */
+        scheduler_tick_t        tick;
+        schedule_t              schedule;
+        finish_switch_t         finish_switch;
+
+        /*      syscall backend         */
+        complete_job_t          complete_job;
+        release_at_t            release_at;
+
+        /*      task state changes      */
+        admit_task_t            admit_task;
+
+        task_new_t              task_new;
+        task_wake_up_t          task_wake_up;
+        task_block_t            task_block;
+        task_exit_t             task_exit;
+
+#ifdef CONFIG_FMLP
+        /*     priority inheritance     */
+        unsigned int            fmlp_active;
+        inherit_priority_t      inherit_priority;
+        return_priority_t       return_priority;
+        pi_block_t              pi_block;
+#endif
+} __attribute__ ((__aligned__(SMP_CACHE_BYTES)));
+
+
+extern struct sched_plugin *litmus;
+
+int register_sched_plugin(struct sched_plugin* plugin);
+struct sched_plugin* find_sched_plugin(const char* name);
+int print_sched_plugins(char* buf, int max);
+
+static inline int srp_active(void)
+{
+#ifdef CONFIG_SRP
+        return litmus->srp_active;
+#else
+        return 0;
+#endif
+}
+static inline int fmlp_active(void)
+{
+#ifdef CONFIG_FMLP
+        return litmus->fmlp_active;
+#else
+        return 0;
+#endif
+}
+
+extern struct sched_plugin linux_sched_plugin;
+
+#endif