cleanup: tidy up code before release2007.2

This gets rid of quite a few FIXMEs and TODOs, as well as some cruft.

12 files changed, 22 insertions, 230 deletions

diff --git a/include/linux/litmus.h b/include/linux/litmus.h
index dc39ecbf7e..259594e922 100644
--- a/include/linux/litmus.h
+++ b/include/linux/litmus.h
@@ -35,7 +35,6 @@ typedef enum {
 typedef enum {
         LITMUS_RESERVED_RANGE = 1024,
        
-        ENABLE_WEIGHT_CHANGE_SIGNAL
 } sched_setup_cmd_t;
 
 /*      Runtime modes */
@@ -49,30 +48,14 @@ enum rt_mode_t {
 #define PLUGIN_PFAIR            "pfair"
 #define PLUGIN_PART_EDF         "part_edf"
 #define PLUGIN_GLOBAL_EDF       "global_edf"
-#define PLUGIN_PFAIR_STAGGER    "stagger"
-#define PLUGIN_PFAIR_DESYNC     "desync"
 #define PLUGIN_GLOBAL_EDF_NP    "global_edf_np"
 #define PLUGIN_EDF_HSB          "edf_hsb"
 #define PLUGIN_GSN_EDF          "gsn_edf"
 #define PLUGIN_PSN_EDF          "psn_edf"
 #define PLUGIN_ADAPTIVE         "adaptive"
 
-/*      Additional clone flags  
-        Indicates that the thread is to be used in 
-        realtime mode, therefore it should not be 
-        woken up in a linux manner,
-        we just set its state to TASK_STOPPED
-        It must be prepared and added to the ready queue explicitly
-*/
-
-/*      Type definition for our quantums */
-typedef unsigned long long quantum_t;
-
 extern spolicy sched_policy;
 
-extern unsigned long slot_size;
-extern unsigned long stagger_offset;
-
 /*      RT mode start time      */
 extern volatile unsigned long rt_start_time;
 
@@ -82,10 +65,6 @@ extern atomic_t rt_mode;
 #define get_rt_mode() (atomic_read(&rt_mode))
 #define set_rt_mode(a) atomic_set(&rt_mode,(a))
 
-/* CLEANUP: Should be queue_lock, does it really belong here? */
-extern  spinlock_t litmus_task_set_lock;
-
-
 #define TRACE(fmt, args...) \
         sched_trace_log_message("%d: " fmt, raw_smp_processor_id(), ## args)
 
@@ -99,7 +78,7 @@ extern  spinlock_t litmus_task_set_lock;
         do { if (cond) TRACE("BUG_ON(%s) at %s:%d " \
                              "called from %p current=%s/%d state=%d " \
                              "flags=%x mode=%d partition=%d cpu=%d rtflags=%d"\
-                             " job=%u knp=%d timeslice=%u\n",                   \
+                             " job=%u knp=%d timeslice=%u\n",           \
         #cond, __FILE__, __LINE__, __builtin_return_address(0), current->comm, \
         current->pid, current->state, current->flags, get_rt_mode(), \
         get_partition(current), smp_processor_id(), get_rt_flags(current), \
diff --git a/include/linux/pfair_math.h b/include/linux/pfair_math.h
index dab1778f0b..b2a14e4c54 100644
--- a/include/linux/pfair_math.h
+++ b/include/linux/pfair_math.h
@@ -7,6 +7,9 @@
 #include <linux/litmus.h>
 #include <linux/sched.h>
 
+/*      Type definition for our quantums */
+typedef unsigned long long quantum_t;
+
 /*
 * This file defines  mathematical functions "ceiling", "floor",
 * and PFAIR specific functions for computing the release and
diff --git a/include/linux/sched_plugin.h b/include/linux/sched_plugin.h
index fa0716f0eb..1ea8178b25 100644
--- a/include/linux/sched_plugin.h
+++ b/include/linux/sched_plugin.h
@@ -33,13 +33,6 @@ struct pi_semaphore {
  */
 typedef void runqueue_t;
 
-/********************* real-time callbacks ********************/
-
-/*      Special plugin shutdown hook that clear plugin data structures 
-        Currently is not supported
-*/
-typedef void (*plugin_shutdown_hook_t) (void);
-
 
 /********************* scheduler invocation ******************/
 
@@ -105,7 +98,6 @@ struct sched_plugin {
         int                     ready_to_use;
 
         /*      management interface    */
-        plugin_shutdown_hook_t  shutdown_hook; /*currently unsupported */
         mode_change_t           mode_change;
 
         /*      scheduler invocation    */
diff --git a/kernel/litmus.c b/kernel/litmus.c
index ee1e09a627..8f238ba979 100644
--- a/kernel/litmus.c
+++ b/kernel/litmus.c
@@ -19,25 +19,22 @@
 spolicy sched_policy            = SCHED_DEFAULT;
 int     sched_options           = 0;
 
-/*      avoid races with multiple task wake-ups */
-DEFINE_SPINLOCK(litmus_task_set_lock);
 
 /* This is a flag for switching the system into RT mode when it is booted up 
- * In RT-mode non-realtime tasks are shut down and scheduled as spare  
- * time available
+ * In RT-mode non-realtime tasks are scheduled as background tasks.
  */
 
-/*      The system is booting in non-realtime mode */
+/* The system is booting in non-realtime mode */
 atomic_t rt_mode                = ATOMIC_INIT(MODE_NON_RT);
-/*      Here we specify a mode change to be made */
+/* Here we specify a mode change to be made */
 atomic_t new_mode               = ATOMIC_INIT(MODE_NON_RT);
-/*      Number of RT tasks that exist in the system */
+/* Number of RT tasks that exist in the system */
 atomic_t n_rt_tasks             = ATOMIC_INIT(0);
 
-/*      Only one process can perform mode change */
+/* Only one CPU may perform a mode change. */
 static queuelock_t mode_change_lock;
 
-/*      A time instant when we switched to RT mode */
+/* The time instant when we switched to RT mode */
 volatile jiffie_t rt_start_time = 0;
 
 /* To send signals from the scheduler 
diff --git a/kernel/sched.c b/kernel/sched.c
index d7fd42a431..5ad4276e4b 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -61,9 +61,11 @@
 #include <linux/sched_plugin.h>
 #include <linux/sched_trace.h>
 #include <linux/rt_param.h>
-
 #include <linux/trace.h>
 
+/* LITMUS: avoid races with multiple task wake-ups */
+DEFINE_SPINLOCK(litmus_task_set_lock);
+
 /*
  * Convert user-nice values [ -20 ... 0 ... 19 ]
  * to static priority [ MAX_RT_PRIO..MAX_PRIO-1 ],
@@ -1693,7 +1695,6 @@ void fastcall wake_up_new_task(struct task_struct *p, unsigned long clone_flags)
 
         if (clone_flags & CLONE_REALTIME) {
                 /* just mark the task as stopped */
-                /* CLEANUP: Do we have to remove the task from the rq? */
                 p->state = TASK_STOPPED;
                 return;
         }
@@ -5541,7 +5542,7 @@ static struct notifier_block __cpuinitdata migration_notifier = {
         .priority = 10
 };
 
-int __init linux_migration_init(void)
+int __init migration_init(void)
 {
         void *cpu = (void *)(long)smp_processor_id();
         int err;
@@ -7003,7 +7004,7 @@ static int update_sched_domains(struct notifier_block *nfb,
         return NOTIFY_OK;
 }
 
-void __init linux_sched_init_smp(void)
+void __init sched_init_smp(void)
 {
         cpumask_t non_isolated_cpus;
 
@@ -7036,7 +7037,7 @@ int in_sched_functions(unsigned long addr)
                 && addr < (unsigned long)__sched_text_end);
 }
 
-void __init linux_sched_init(void)
+void __init sched_init(void)
 {
         int i, j, k;
 
diff --git a/kernel/sched_adaptive.c b/kernel/sched_adaptive.c
index 97d06b1ad4..319ebbc11c 100644
--- a/kernel/sched_adaptive.c
+++ b/kernel/sched_adaptive.c
@@ -838,8 +838,6 @@ static noinline void preempt(cpu_entry_t *entry)
         } else
                 /* in case that it is a remote CPU we have to defer the
                  * the decision to the remote CPU
-                 * FIXME: We could save a few IPI's here if we leave the flag
-                 * set when we are waiting for a np_exit().
                  */
                 if (!test_will_schedule(entry->cpu))
                         smp_send_reschedule(entry->cpu);
@@ -1432,7 +1430,7 @@ sched_plugin_t *__init init_adaptive_plugin(void)
         fc_b = _frac(  303, 1000);
         
         optimizer_period = 1000;
-        optimizer_min_invocation_sep = 50;
+        optimizer_min_invocation_sep = 200;
         task_error_threshold = _frac(1, 2);
 
         if (!s_plugin.ready_to_use)
diff --git a/kernel/sched_edf_hsb.c b/kernel/sched_edf_hsb.c
index c2a4c6c679..a2f670d994 100644
--- a/kernel/sched_edf_hsb.c
+++ b/kernel/sched_edf_hsb.c
@@ -1077,52 +1077,6 @@ static struct task_struct* null_heuristic(struct task_struct *prev,
                 return NULL;
 }
 
-/*static struct task_struct* history_heuristic(struct task_struct *prev, rt_domain_t* edf)
-{
-        struct list_head *pos;
-        struct task_struct* tsk = NULL;
-        struct task_struct* cur;
-
-        if (is_realtime(prev) && is_running(prev) && 
-            get_rt_flags(prev) != RT_F_SLEEP)
-                tsk = prev;
-        list_for_each(pos, &edf->ready_queue) {
-                cur = list_entry(pos, struct task_struct, rt_list);
-                if (!tsk || 
-                    tsk->rt_param.stats.nontardy_jobs_ctr > 
-                    cur->rt_param.stats.nontardy_jobs_ctr)
-                        tsk = cur;              
-        }
-        if (tsk && tsk->rt_param.stats.nontardy_jobs_ctr < 5)
-                return tsk;
-        else
-                return NULL;
-}
-*/
-/* TODO: write slack heuristic.*/
-/*static struct task_struct* slack_heuristic(struct task_struct *prev, rt_domain_t* edf)
-{
-        struct list_head *pos;
-        struct task_struct* tsk = NULL;
-        struct task_struct* cur;
-
-        if (is_realtime(prev) && is_running(prev) && 
-            get_rt_flags(prev) != RT_F_SLEEP)
-                tsk = prev;
-        list_for_each(pos, &edf->ready_queue) {
-                cur = list_entry(pos, struct task_struct, rt_list);
-                if (!tsk || 
-                    tsk->rt_param.stats.nontardy_job_ctr > 
-                    cur->rt_param.stats.nontardy_job_ctr)
-                        tsk = cur;              
-        }
-        if (tsk && tsk->rt_param.stats.nontardy_job_ctr < 5)
-                return tsk;
-        else
-                return NULL;
-}*/
-
-
 /* caller holds all locks
  */
 
@@ -1229,7 +1183,7 @@ static int schedule_srt_be_cap(struct task_struct *prev,
         int             deactivate = 1;
         be_server_t*    bes;
         cpu_state_t*    state;
-        int             type; /* FIXME: Initialize? */
+        int             type = BG; 
 
 reschedule:     
         write_lock_irqsave(&srt.ready_lock, flags);
@@ -1531,9 +1485,6 @@ static void hsb_wake_up_task(struct task_struct *task)
         }
         else if (task->time_slice) {
                 /* came back in time before deadline
-                 * TODO: clip budget to fit into period, otherwise it could 
-                 *       cause a deadline overrun in the next period, i.e. 
-                 *       over allocation in the next period.
                  */
                 set_rt_flags(task, RT_F_RUNNING);
                 hsb_add_ready(task);
@@ -1546,43 +1497,16 @@ static void hsb_wake_up_task(struct task_struct *task)
 
 static void hsb_task_blocks(struct task_struct *t)
 {
-        /* CLEANUP: The BUG_ON actually triggerd in a really weierd case if a 
-         *          BEST_EFFORT gets caught in a migration right after execv
-         *          The next version of Litmus should deal with this more gracefully.
-         */
-
-        /*BUG_ON(!is_realtime(t));*/
         /* not really anything to do since it can only block if 
          * it is running, and when it is not running it is not in any 
          * queue anyway.
-         *
-         * TODO: Check whether the assumption is correct for SIGKILL and 
-         *       SIGSTOP.
          */
         TRACE("task %d blocks with budget=%d\n", t->pid, t->time_slice);
-        /*BUG_ON(t->rt_list.next != LIST_POISON1);*/
-        /*BUG_ON(t->rt_list.prev != LIST_POISON2);*/
-
         if (is_be(t))
                 sched_trace_job_completion(t);
 }
 
 
-/* When _tear_down is called, the task should not be in any queue any more
- * as it must have blocked first. We don't have any internal state for the task,
- * it is all in the task_struct.
- */
-static long hsb_tear_down(struct task_struct * t)
-{
-        /* CLEANUP: see hsb_task_blocks */
-        /*BUG_ON(!is_realtime(t));
-        TRACE("edf-hsb: tear down called for %d \n", t->pid);
-        BUG_ON(t->array);
-        BUG_ON(t->rt_list.next != LIST_POISON1);
-        BUG_ON(t->rt_list.prev != LIST_POISON2);*/
-        return 0;
-}
-
 static int hsb_mode_change(int new_mode)
 {
         int cpu;
@@ -1769,8 +1693,6 @@ static sched_plugin_t s_plugin __cacheline_aligned_in_smp = {
         .scheduler_tick         = hsb_scheduler_tick,\
         .prepare_task           = hsb_prepare_task,\
         .sleep_next_period      = edf_sleep_next_period,\
-        .tear_down              = hsb_tear_down,\
-        .shutdown_hook          = 0,\
         .schedule               = hsb_schedule,\
         .finish_switch          = hsb_finish_switch,\
         .mode_change            = hsb_mode_change,\
@@ -1789,7 +1711,6 @@ sched_plugin_t *__init init_edf_hsb_plugin(void)
                 capacity_queue_init(&cap_queue);
                 edf_domain_init(&srt, srt_check_resched);
                 edf_domain_init(&be, be_check_resched);
-                /* TODO: Re-implement FIFO time slicing, was 50ms. */
                 fifo_domain_init(&hsb_fifo, NULL);
                 for (i = 0; i < NR_CPUS; i++)
                 {
diff --git a/kernel/sched_global_edf.c b/kernel/sched_global_edf.c
index 6e3928b7df..4b36bc5a48 100644
--- a/kernel/sched_global_edf.c
+++ b/kernel/sched_global_edf.c
@@ -64,7 +64,6 @@ static void adjust_cpu_queue(int exec_rt, jiffie_t deadline)
         entry->executes_realtime = exec_rt;
         entry->cur_deadline      = deadline;
 
-        /* TODO: move instead of del+reinsert */
         list_del(&entry->list);
         /* if we do not execute real-time jobs we just move 
          * to the end of the queue 
@@ -94,10 +93,6 @@ static void adjust_cpu_queue(int exec_rt, jiffie_t deadline)
  * kick the next if necessary, and so on. The caller is responsible for making
  * sure that it is not the last entry or that a reschedule is not necessary.
  *
- * TODO: This function is probably way too trigger happy. It should only send
- *       IPIs if the other CPU is not  going to reschedule anyway. But that is 
- *       hard to detect reliably. Too many schedules will hurt performance 
- *       but do not cause incorrect schedules.
  */
 static int gedf_check_resched(rt_domain_t *edf) 
 {
@@ -336,9 +331,6 @@ static void gedf_wake_up_task(struct task_struct *task)
         }
         else if (task->time_slice) {
                 /* came back in time before deadline
-                 * TODO: clip budget to fit into period, otherwise it could 
-                 *       cause a deadline overrun in the next period, i.e. 
-                 *       over allocation in the next period.
                  */
                 set_rt_flags(task, RT_F_RUNNING);
                 add_ready(&gedf, task);
@@ -356,8 +348,6 @@ static void gedf_task_blocks(struct task_struct *t)
          * it is running, and when it is not running it is not in any 
          * queue anyway.
          *
-         * TODO: Check whether the assumption is correct for SIGKILL and 
-         *       SIGSTOP.
          */
         TRACE("task %d blocks with budget=%d\n", t->pid, t->time_slice);
         BUG_ON(t->rt_list.next != LIST_POISON1);
@@ -433,7 +423,6 @@ static sched_plugin_t s_plugin __cacheline_aligned_in_smp = {
         .prepare_task           = gedf_prepare_task,\
         .sleep_next_period      = edf_sleep_next_period,\
         .tear_down              = gedf_tear_down,\
-        .shutdown_hook          = 0,\
         .schedule               = gedf_schedule,\
         .finish_switch          = gedf_finish_switch,\
         .mode_change            = gedf_mode_change,\
@@ -538,7 +527,6 @@ static int gedf_np_check_resched(rt_domain_t *edf)
         .prepare_task           = gedf_prepare_task,\
         .sleep_next_period      = edf_sleep_next_period,\
         .tear_down              = gedf_tear_down,\
-        .shutdown_hook          = 0,\
         .schedule               = gedf_schedule,\
         .finish_switch          = gedf_finish_switch,\
         .mode_change            = gedf_mode_change,\
diff --git a/kernel/sched_part_edf.c b/kernel/sched_part_edf.c
index 8166c8f4c6..a792ac5d03 100644
--- a/kernel/sched_part_edf.c
+++ b/kernel/sched_part_edf.c
@@ -241,10 +241,10 @@ static void part_edf_wake_up_task(struct task_struct *task)
                 add_ready(edf, task);
 
         } else if (task->time_slice) {
-                /* came back in time before deadline
-                 * TODO: clip budget to fit into period, otherwise it could 
-                 *       cause a deadline overrun in the next period, i.e. 
-                 *       over allocation in the next period.
+                /* Came back in time before deadline. This may cause
+                 * deadline overruns, but since we don't handle suspensions
+                 * in the analytical model, we don't care since we can't
+                 * guarantee anything at all if tasks block.
                  */
                 set_rt_flags(task, RT_F_RUNNING);
                 add_ready(edf, task);
@@ -262,8 +262,6 @@ static void part_edf_task_blocks(struct task_struct *t)
          * it is running, and when it is not running it is not in any 
          * queue anyway.
          *
-         * TODO: Check whether the assumption is correct for SIGKILL and 
-         *       SIGSTOP.
          */
         TRACE("task %d blocks with budget=%d\n", t->pid, t->time_slice);
         BUG_ON(in_list(&t->rt_list));
@@ -313,7 +311,6 @@ static sched_plugin_t s_plugin __cacheline_aligned_in_smp = {
         .prepare_task           = part_edf_prepare_task,\
         .sleep_next_period      = edf_sleep_next_period,\
         .tear_down              = part_edf_tear_down,\
-        .shutdown_hook          = NULL,\
         .schedule               = part_edf_schedule,\
         .finish_switch          = part_edf_finish_switch,\
         .mode_change            = part_edf_mode_change,\
diff --git a/kernel/sched_pfair.c b/kernel/sched_pfair.c
index 20a7526a0a..1a6a790fb7 100644
--- a/kernel/sched_pfair.c
+++ b/kernel/sched_pfair.c
@@ -480,9 +480,7 @@ static sched_plugin_t s_plugin __cacheline_aligned_in_smp = {
         .ready_to_use           = 1,\
         .scheduler_tick         = pfair_scheduler_tick,\
         .prepare_task           = pfair_prepare_task,\
-        .sleep_next_period      = 0,\
         .tear_down              = pfair_tear_down,\
-        .shutdown_hook          = 0,\
         .schedule               = pfair_schedule,\
         .finish_switch          = pfair_finish_task_switch,\
         .mode_change            = pfair_mode_change,\
diff --git a/kernel/sched_plugin.c b/kernel/sched_plugin.c
index 3c7d6c0842..1f759b7c9f 100644
--- a/kernel/sched_plugin.c
+++ b/kernel/sched_plugin.c
@@ -9,14 +9,6 @@
 #include <linux/sched_plugin.h>
 
 
-/* These are the original Linux initialization functions.
- * We replace them here with our initialization code and call them
- * after setting up LITMUS.
- */
-void linux_sched_init(void);
-void linux_sched_init_smp(void);
-int  linux_migration_init(void);
-
 /*************************************************************
  *                   Dummy plugin functions                  *
  *************************************************************/
@@ -99,7 +91,6 @@ sched_plugin_t linux_sched_plugin = {
         .wake_up_task = litmus_dummy_wake_up_task,
         .task_blocks = litmus_dummy_task_blocks,
         .sleep_next_period = litmus_dummy_sleep_next_period,
-        .shutdown_hook = 0,
         .schedule = litmus_dummy_schedule,
         .finish_switch = litmus_dummy_finish_switch,
         .scheduler_setup = litmus_dummy_scheduler_setup,
@@ -115,47 +106,3 @@ sched_plugin_t linux_sched_plugin = {
  */
 sched_plugin_t *curr_sched_plugin = &linux_sched_plugin;
 
-
-/*      At sched-init */
-void __init sched_init(void)
-{
-        printk("Entering custom sched init, plugin %s\n",
-               curr_sched_plugin->plugin_name);
-        /*      Init tracing facility before plugin functions are called */
-
-        /* CLEANUP: reenable this if needed
-          pstats = INIT_PSTATS;
-
-         */
-
-        /*      Call linux sched init tasks */
-        linux_sched_init();
-        printk("Sched init complete\n");
-}
-
-void __init sched_init_smp(void)
-{
-        printk("Entering custom SMP init, plugin %s\n",
-               curr_sched_plugin->plugin_name);
-        /*      Call linux smp initializer      */
-        linux_sched_init_smp();
-        /*      Enable tracing facilities here */
-        /*
-          CLEANUP: Reenable if needed.
-        if (smp_processor_id() == 0) {
-                if (init_trace()) {
-                        printk("Tracing disabled\n");
-                } else {
-                        printk("Default tracing enabled\n");
-                }
-                } */
-        printk("Sched init SMP complete\n");
-}
-
-int __init migration_init(void)
-{
-        printk("Entering migration init\n");
-
-        /*      Call linux migration init as it was before */
-        return linux_migration_init();
-}
diff --git a/kernel/sched_psn_edf.c b/kernel/sched_psn_edf.c
index 32f9b23829..9e4f4abd52 100644
--- a/kernel/sched_psn_edf.c
+++ b/kernel/sched_psn_edf.c
@@ -301,39 +301,11 @@ static void psnedf_wake_up_task(struct task_struct *task)
         TRACE("psnedf: %d unsuspends with budget=%d\n", 
               task->pid, task->time_slice);
 
-
         /* After fixing the litmus_controlled bug,
          * this should hold again.
          */
         BUG_ON(in_list(&task->rt_list));
 
-        /* FIXME:
-         * There exists a race between this function, suspensions due to IO,
-         * and switching in and out of real-time mode. For some reason, the
-         * BUG_ON triggered after a task system warm-up phase.
-         *
-         *      BUG_ON(in_list(&task->rt_list));
-         *
-         * Replaced by an if to gather more information.
-         */
-/*      
-        if (unlikely(in_list(&task->rt_list))) {
-                TRACE(KERN_CRIT "wake_up_task: Why is %s/%d in rt list? "
-                       "state=%ld next=%p prev=%p flags=0x%8lx mode=%d "
-                       "partition=%d cpu=%d deadline=%ld now=%ld release=%ld"
-                       "rtflags=%d timeslice=%d job=%u knp=%d",
-                       task->comm, task->pid,
-                       task->state, task->rt_list.next, task->rt_list.prev, 
-                       task->flags, get_rt_mode(),
-                       get_partition(task), smp_processor_id(),
-                       get_deadline(task), jiffies, get_release(task),
-                       get_rt_flags(task), task->time_slice,
-                       task->rt_param.times.job_no, task->rt_param.kernel_np);
-                task->state = TASK_RUNNING;
-                return;
-        }
-*/
-
         task->state = TASK_RUNNING;
 
         /* We need to take suspensions because of semaphores into
@@ -520,7 +492,6 @@ static sched_plugin_t s_plugin __cacheline_aligned_in_smp = {
         .prepare_task           = psnedf_prepare_task,\
         .sleep_next_period      = edf_sleep_next_period,\
         .tear_down              = psnedf_tear_down,\
-        .shutdown_hook          = NULL,\
         .schedule               = psnedf_schedule,\
         .mode_change            = psnedf_mode_change,\
         .wake_up_task           = psnedf_wake_up_task,\