This patch introduces core changes in CFS work to operate on generic
schedulable entities. The task specific operations (like enqueue, dequeue, 
task_tick etc) is then rewritten to work off this generic CFS "library".

Signed-off-by : Srivatsa Vaddagiri <[EMAIL PROTECTED]>


---
 kernel/sched_debug.c |    2 
 kernel/sched_fair.c  |  574 ++++++++++++++++++++++++++++++---------------------
 2 files changed, 345 insertions(+), 231 deletions(-)

Index: current/kernel/sched_fair.c
===================================================================
--- current.orig/kernel/sched_fair.c    2007-06-09 15:07:16.000000000 +0530
+++ current/kernel/sched_fair.c 2007-06-09 15:07:33.000000000 +0530
@@ -42,19 +42,54 @@
 
 extern struct sched_class fair_sched_class;
 
+/******************************************************************************/
+/*            BEGIN : CFS operations on generic schedulable entities          
*/
+/******************************************************************************/
+
+static inline struct rq *lrq_rq(struct lrq *lrq)
+{
+       return container_of(lrq, struct rq, lrq);
+}
+
+static inline struct sched_entity *lrq_curr(struct lrq *lrq)
+{
+       struct rq *rq = lrq_rq(lrq);
+       struct sched_entity *se = NULL;
+
+       if (rq->curr->sched_class == &fair_sched_class)
+               se = &rq->curr->se;
+
+       return se;
+}
+
+static long lrq_nr_running(struct lrq *lrq)
+{
+       struct rq *rq = lrq_rq(lrq);
+
+       return rq->nr_running;
+}
+
+#define entity_is_task(se)     1
+
+static inline struct task_struct *entity_to_task(struct sched_entity *se)
+{
+       return container_of(se, struct task_struct, se);
+}
+
+
 /**************************************************************/
 /* Scheduling class tree data structure manipulation methods:
  */
 
 /*
- * Enqueue a task into the rb-tree:
+ * Enqueue a entity into the rb-tree:
  */
-static inline void __enqueue_task_fair(struct rq *rq, struct task_struct *p)
+static inline void __enqueue_entity(struct lrq *lrq, struct sched_entity *p)
 {
-       struct rb_node **link = &rq->lrq.tasks_timeline.rb_node;
+       struct rb_node **link = &lrq->tasks_timeline.rb_node;
        struct rb_node *parent = NULL;
-       struct task_struct *entry;
-       s64 key = p->se.fair_key;
+       struct sched_entity *entry;
+       s64 key = p->fair_key;
        int leftmost = 1;
 
        /*
@@ -62,12 +97,12 @@
         */
        while (*link) {
                parent = *link;
-               entry = rb_entry(parent, struct task_struct, se.run_node);
+               entry = rb_entry(parent, struct sched_entity, run_node);
                /*
                 * We dont care about collisions. Nodes with
                 * the same key stay together.
                 */
-               if ((s64)(key - entry->se.fair_key) < 0) {
+               if ((s64)(key - entry->fair_key) < 0) {
                        link = &parent->rb_left;
                } else {
                        link = &parent->rb_right;
@@ -80,31 +115,31 @@
         * used):
         */
        if (leftmost)
-               rq->lrq.rb_leftmost = &p->se.run_node;
+               lrq->rb_leftmost = &p->run_node;
 
-       rb_link_node(&p->se.run_node, parent, link);
-       rb_insert_color(&p->se.run_node, &rq->lrq.tasks_timeline);
+       rb_link_node(&p->run_node, parent, link);
+       rb_insert_color(&p->run_node, &lrq->tasks_timeline);
 }
 
-static inline void __dequeue_task_fair(struct rq *rq, struct task_struct *p)
+static inline void __dequeue_entity(struct lrq *lrq, struct sched_entity *p)
 {
-       if (rq->lrq.rb_leftmost == &p->se.run_node)
-               rq->lrq.rb_leftmost = NULL;
-       rb_erase(&p->se.run_node, &rq->lrq.tasks_timeline);
+       if (lrq->rb_leftmost == &p->run_node)
+               lrq->rb_leftmost = NULL;
+       rb_erase(&p->run_node, &lrq->tasks_timeline);
 }
 
-static inline struct rb_node * first_fair(struct rq *rq)
+static inline struct rb_node * first_fair(struct lrq *lrq)
 {
-       if (rq->lrq.rb_leftmost)
-               return rq->lrq.rb_leftmost;
+       if (lrq->rb_leftmost)
+               return lrq->rb_leftmost;
        /* Cache the value returned by rb_first() */
-       rq->lrq.rb_leftmost = rb_first(&rq->lrq.tasks_timeline);
-       return rq->lrq.rb_leftmost;
+       lrq->rb_leftmost = rb_first(&lrq->tasks_timeline);
+       return lrq->rb_leftmost;
 }
 
-static struct task_struct * __pick_next_task_fair(struct rq *rq)
+static struct sched_entity * __pick_next_entity(struct lrq *lrq)
 {
-       return rb_entry(first_fair(rq), struct task_struct, se.run_node);
+       return rb_entry(first_fair(lrq), struct sched_entity, run_node);
 }
 
 /**************************************************************/
@@ -116,21 +151,21 @@
  * nice level, but only linearly, not exponentially:
  */
 static u64
-niced_granularity(struct task_struct *curr, unsigned long granularity)
+niced_granularity(struct sched_entity *curr, unsigned long granularity)
 {
        /*
         * Negative nice levels get the same granularity as nice-0:
         */
-       if (curr->se.load_weight >= NICE_0_LOAD)
+       if (curr->load_weight >= NICE_0_LOAD)
                return granularity;
        /*
         * Positive nice level tasks get linearly finer
         * granularity:
         */
-       return curr->se.load_weight * (s64)(granularity / NICE_0_LOAD);
+       return curr->load_weight * (s64)(granularity / NICE_0_LOAD);
 }
 
-static void limit_wait_runtime(struct rq *rq, struct task_struct *p)
+static void limit_wait_runtime(struct lrq *lrq, struct sched_entity *p)
 {
        s64 limit = sysctl_sched_runtime_limit;
 
@@ -138,30 +173,31 @@
         * Niced tasks have the same history dynamic range as
         * non-niced tasks:
         */
-       if (p->se.wait_runtime > limit) {
-               p->se.wait_runtime = limit;
-               p->se.wait_runtime_overruns++;
-               rq->lrq.wait_runtime_overruns++;
-       }
-       if (p->se.wait_runtime < -limit) {
-               p->se.wait_runtime = -limit;
-               p->se.wait_runtime_underruns++;
-               rq->lrq.wait_runtime_underruns++;
+       if (p->wait_runtime > limit) {
+               p->wait_runtime = limit;
+               p->wait_runtime_overruns++;
+               lrq->wait_runtime_overruns++;
+       }
+       if (p->wait_runtime < -limit) {
+               p->wait_runtime = -limit;
+               p->wait_runtime_underruns++;
+               lrq->wait_runtime_underruns++;
        }
 }
 
-static void __add_wait_runtime(struct rq *rq, struct task_struct *p, s64 delta)
+static void
+__add_wait_runtime(struct lrq *lrq, struct sched_entity *p, s64 delta)
 {
-       p->se.wait_runtime += delta;
-       p->se.sum_wait_runtime += delta;
-       limit_wait_runtime(rq, p);
+       p->wait_runtime += delta;
+       p->sum_wait_runtime += delta;
+       limit_wait_runtime(lrq, p);
 }
 
-static void add_wait_runtime(struct rq *rq, struct task_struct *p, s64 delta)
+static void add_wait_runtime(struct lrq *lrq, struct sched_entity *p, s64 
delta)
 {
-       rq->lrq.wait_runtime -= p->se.wait_runtime;
-       __add_wait_runtime(rq, p, delta);
-       rq->lrq.wait_runtime += p->se.wait_runtime;
+       lrq->wait_runtime -= p->wait_runtime;
+       __add_wait_runtime(lrq, p, delta);
+       lrq->wait_runtime += p->wait_runtime;
 }
 
 static s64 div64_s(s64 divident, unsigned long divisor)
@@ -183,49 +219,51 @@
  * Update the current task's runtime statistics. Skip current tasks that
  * are not in our scheduling class.
  */
-static inline void update_curr(struct rq *rq, u64 now)
+static inline void update_curr(struct lrq *lrq, u64 now)
 {
-       unsigned long load = rq->lrq.raw_weighted_load;
+       unsigned long load = lrq->raw_weighted_load;
        u64 delta_exec, delta_fair, delta_mine;
-       struct task_struct *curr = rq->curr;
+       struct sched_entity *curr = lrq_curr(lrq);
+       struct rq *rq = lrq_rq(lrq);
+       struct task_struct *curtask = rq->curr;
 
-       if (curr->sched_class != &fair_sched_class || curr == rq->idle || !load)
+       if (!curr || curtask == rq->idle || !load)
                return;
        /*
         * Get the amount of time the current task was running
         * since the last time we changed raw_weighted_load:
         */
-       delta_exec = now - curr->se.exec_start;
+       delta_exec = now - curr->exec_start;
        if (unlikely((s64)delta_exec < 0))
                delta_exec = 0;
-       if (unlikely(delta_exec > curr->se.exec_max))
-               curr->se.exec_max = delta_exec;
+       if (unlikely(delta_exec > curr->exec_max))
+               curr->exec_max = delta_exec;
 
-       curr->se.sum_exec_runtime += delta_exec;
-       curr->se.exec_start = now;
-       rq->lrq.exec_clock += delta_exec;
+       curr->sum_exec_runtime += delta_exec;
+       curr->exec_start = now;
+       lrq->exec_clock += delta_exec;
 
        delta_fair = delta_exec * NICE_0_LOAD;
        delta_fair += load >> 1; /* rounding */
        do_div(delta_fair, load);
 
        /* Load-balancing accounting. */
-       rq->lrq.delta_fair_clock += delta_fair;
-       rq->lrq.delta_exec_clock += delta_exec;
+       lrq->delta_fair_clock += delta_fair;
+       lrq->delta_exec_clock += delta_exec;
 
        /*
         * Task already marked for preemption, do not burden
         * it with the cost of not having left the CPU yet:
         */
        if (unlikely(sysctl_sched_features & 1))
-               if (unlikely(test_tsk_thread_flag(curr, TIF_NEED_RESCHED)))
+               if (unlikely(test_tsk_thread_flag(curtask, TIF_NEED_RESCHED)))
                        return;
 
-       delta_mine = delta_exec * curr->se.load_weight;
+       delta_mine = delta_exec * curr->load_weight;
        delta_mine += load >> 1; /* rounding */
        do_div(delta_mine, load);
 
-       rq->lrq.fair_clock += delta_fair;
+       lrq->fair_clock += delta_fair;
        /*
         * We executed delta_exec amount of time on the CPU,
         * but we were only entitled to delta_mine amount of
@@ -233,21 +271,21 @@
         * the two values are equal)
         * [Note: delta_mine - delta_exec is negative]:
         */
-       add_wait_runtime(rq, curr, delta_mine - delta_exec);
+       add_wait_runtime(lrq, curr, delta_mine - delta_exec);
 }
 
 static inline void
-update_stats_wait_start(struct rq *rq, struct task_struct *p, u64 now)
+update_stats_wait_start(struct lrq *lrq, struct sched_entity *p, u64 now)
 {
-       p->se.wait_start_fair = rq->lrq.fair_clock;
-       p->se.wait_start = now;
+       p->wait_start_fair = lrq->fair_clock;
+       p->wait_start = now;
 }
 
 /*
  * Task is being enqueued - update stats:
  */
 static inline void
-update_stats_enqueue(struct rq *rq, struct task_struct *p, u64 now)
+update_stats_enqueue(struct lrq *lrq, struct sched_entity *p, u64 now)
 {
        s64 key;
 
@@ -255,86 +293,86 @@
         * Are we enqueueing a waiting task? (for current tasks
         * a dequeue/enqueue event is a NOP)
         */
-       if (p != rq->curr)
-               update_stats_wait_start(rq, p, now);
+       if (p != lrq_curr(lrq))
+               update_stats_wait_start(lrq, p, now);
        /*
         * Update the key:
         */
-       key = rq->lrq.fair_clock;
+       key = lrq->fair_clock;
 
        /*
         * Optimize the common nice 0 case:
         */
-       if (likely(p->se.load_weight == NICE_0_LOAD))
-               key -= p->se.wait_runtime;
+       if (likely(p->load_weight == NICE_0_LOAD))
+               key -= p->wait_runtime;
        else {
-               if (p->se.wait_runtime < 0)
-                       key -= div64_s(p->se.wait_runtime * NICE_0_LOAD,
-                                                        p->se.load_weight);
+               if (p->wait_runtime < 0)
+                       key -= div64_s(p->wait_runtime * NICE_0_LOAD,
+                                                        p->load_weight);
                else
-                       key -= div64_s(p->se.wait_runtime * p->se.load_weight,
+                       key -= div64_s(p->wait_runtime * p->load_weight,
                                                                NICE_0_LOAD);
        }
 
-       p->se.fair_key = key;
+       p->fair_key = key;
 }
 
 /*
  * Note: must be called with a freshly updated rq->fair_clock.
  */
 static inline void
-update_stats_wait_end(struct rq *rq, struct task_struct *p, u64 now)
+update_stats_wait_end(struct lrq *lrq, struct sched_entity *p, u64 now)
 {
        s64 delta_fair, delta_wait;
 
-       delta_wait = now - p->se.wait_start;
-       if (unlikely(delta_wait > p->se.wait_max))
-               p->se.wait_max = delta_wait;
+       delta_wait = now - p->wait_start;
+       if (unlikely(delta_wait > p->wait_max))
+               p->wait_max = delta_wait;
 
-       if (p->se.wait_start_fair) {
-               delta_fair = rq->lrq.fair_clock - p->se.wait_start_fair;
+       if (p->wait_start_fair) {
+               delta_fair = lrq->fair_clock - p->wait_start_fair;
 
-               if (unlikely(p->se.load_weight != NICE_0_LOAD))
-                       delta_fair = div64_s(delta_fair * p->se.load_weight,
+               if (unlikely(p->load_weight != NICE_0_LOAD))
+                       delta_fair = div64_s(delta_fair * p->load_weight,
                                                                NICE_0_LOAD);
-               add_wait_runtime(rq, p, delta_fair);
+               add_wait_runtime(lrq, p, delta_fair);
        }
 
-       p->se.wait_start_fair = 0;
-       p->se.wait_start = 0;
+       p->wait_start_fair = 0;
+       p->wait_start = 0;
 }
 
 static inline void
-update_stats_dequeue(struct rq *rq, struct task_struct *p, u64 now)
+update_stats_dequeue(struct lrq *lrq, struct sched_entity *p, u64 now)
 {
-       update_curr(rq, now);
+       update_curr(lrq, now);
        /*
         * Mark the end of the wait period if dequeueing a
         * waiting task:
         */
-       if (p != rq->curr)
-               update_stats_wait_end(rq, p, now);
+       if (p != lrq_curr(lrq))
+               update_stats_wait_end(lrq, p, now);
 }
 
 /*
  * We are picking a new current task - update its stats:
  */
 static inline void
-update_stats_curr_start(struct rq *rq, struct task_struct *p, u64 now)
+update_stats_curr_start(struct lrq *lrq, struct sched_entity *p, u64 now)
 {
        /*
         * We are starting a new run period:
         */
-       p->se.exec_start = now;
+       p->exec_start = now;
 }
 
 /*
  * We are descheduling a task - update its stats:
  */
 static inline void
-update_stats_curr_end(struct rq *rq, struct task_struct *p, u64 now)
+update_stats_curr_end(struct lrq *lrq, struct sched_entity *p, u64 now)
 {
-       p->se.exec_start = 0;
+       p->exec_start = 0;
 }
 
 /*
@@ -347,39 +385,41 @@
  * manner we move the fair clock back by a proportional
  * amount of the new wait_runtime this task adds to the pool.
  */
-static void distribute_fair_add(struct rq *rq, s64 delta)
+static void distribute_fair_add(struct lrq *lrq, s64 delta)
 {
-       struct task_struct *curr = rq->curr;
+       struct sched_entity *curr = lrq_curr(lrq);
        s64 delta_fair = 0;
 
        if (!(sysctl_sched_features & 2))
                return;
 
-       if (rq->nr_running) {
-               delta_fair = div64_s(delta, rq->nr_running);
+       if (lrq_nr_running(lrq)) {
+               delta_fair = div64_s(delta, lrq_nr_running(lrq));
                /*
                 * The currently running task's next wait_runtime value does
                 * not depend on the fair_clock, so fix it up explicitly:
                 */
-                if (curr->sched_class == &fair_sched_class)
-                       add_wait_runtime(rq, curr, -delta_fair);
+                if (curr)
+                       add_wait_runtime(lrq, curr, -delta_fair);
        }
-       rq->lrq.fair_clock -= delta_fair;
+       lrq->fair_clock -= delta_fair;
 }
 
 /**************************************************************/
 /* Scheduling class queueing methods:
  */
 
-static void enqueue_sleeper(struct rq *rq, struct task_struct *p)
+static void enqueue_sleeper(struct lrq *lrq, struct sched_entity *p)
 {
-       unsigned long load = rq->lrq.raw_weighted_load;
+       unsigned long load = lrq->raw_weighted_load;
        s64 delta_fair, prev_runtime;
+       struct task_struct *tsk = entity_to_task(p);
 
-       if (p->policy == SCHED_BATCH || !(sysctl_sched_features & 4))
+       if ((entity_is_task(p) && tsk->policy == SCHED_BATCH) ||
+                                                !(sysctl_sched_features & 4))
                goto out;
 
-       delta_fair = rq->lrq.fair_clock - p->se.sleep_start_fair;
+       delta_fair = lrq->fair_clock - p->sleep_start_fair;
 
        /*
         * Fix up delta_fair with the effect of us running
@@ -387,69 +427,206 @@
         */
        if (!(sysctl_sched_features & 32))
                delta_fair = div64_s(delta_fair * load,
-                                                load + p->se.load_weight);
-       delta_fair = div64_s(delta_fair * p->se.load_weight, NICE_0_LOAD);
+                                                load + p->load_weight);
+       delta_fair = div64_s(delta_fair * p->load_weight, NICE_0_LOAD);
 
-       prev_runtime = p->se.wait_runtime;
-       __add_wait_runtime(rq, p, delta_fair);
-       delta_fair = p->se.wait_runtime - prev_runtime;
+       prev_runtime = p->wait_runtime;
+       __add_wait_runtime(lrq, p, delta_fair);
+       delta_fair = p->wait_runtime - prev_runtime;
 
        /*
         * We move the fair clock back by a load-proportional
         * amount of the new wait_runtime this task adds to
         * the 'pool':
         */
-       distribute_fair_add(rq, delta_fair);
+       distribute_fair_add(lrq, delta_fair);
 
 out:
-       rq->lrq.wait_runtime += p->se.wait_runtime;
+       lrq->wait_runtime += p->wait_runtime;
 
-       p->se.sleep_start_fair = 0;
+       p->sleep_start_fair = 0;
 }
 
-/*
- * The enqueue_task method is called before nr_running is
- * increased. Here we update the fair scheduling stats and
- * then put the task into the rbtree:
- */
 static void
-enqueue_task_fair(struct rq *rq, struct task_struct *p, int wakeup, u64 now)
+enqueue_entity(struct lrq *lrq, struct sched_entity *p, int wakeup, u64 now)
 {
        u64 delta = 0;
 
        /*
         * Update the fair clock.
         */
-       update_curr(rq, now);
+       update_curr(lrq, now);
 
        if (wakeup) {
-               if (p->se.sleep_start) {
-                       delta = now - p->se.sleep_start;
+               if (p->sleep_start) {
+                       delta = now - p->sleep_start;
                        if ((s64)delta < 0)
                                delta = 0;
 
-                       if (unlikely(delta > p->se.sleep_max))
-                               p->se.sleep_max = delta;
+                       if (unlikely(delta > p->sleep_max))
+                               p->sleep_max = delta;
 
-                       p->se.sleep_start = 0;
+                       p->sleep_start = 0;
                }
-               if (p->se.block_start) {
-                       delta = now - p->se.block_start;
+               if (p->block_start) {
+                       delta = now - p->block_start;
                        if ((s64)delta < 0)
                                delta = 0;
 
-                       if (unlikely(delta > p->se.block_max))
-                               p->se.block_max = delta;
+                       if (unlikely(delta > p->block_max))
+                               p->block_max = delta;
 
-                       p->se.block_start = 0;
+                       p->block_start = 0;
                }
-               p->se.sum_sleep_runtime += delta;
+               p->sum_sleep_runtime += delta;
 
-               if (p->se.sleep_start_fair)
-                       enqueue_sleeper(rq, p);
+               if (p->sleep_start_fair)
+                       enqueue_sleeper(lrq, p);
        }
-       update_stats_enqueue(rq, p, now);
-       __enqueue_task_fair(rq, p);
+       update_stats_enqueue(lrq, p, now);
+       __enqueue_entity(lrq, p);
+}
+
+static void
+dequeue_entity(struct lrq *lrq, struct sched_entity *p, int sleep, u64 now)
+{
+       update_stats_dequeue(lrq, p, now);
+       if (sleep) {
+               if (entity_is_task(p)) {
+                       struct task_struct *tsk = entity_to_task(p);
+
+                       if (tsk->state & TASK_INTERRUPTIBLE)
+                               p->sleep_start = now;
+                       if (tsk->state & TASK_UNINTERRUPTIBLE)
+                               p->block_start = now;
+               }
+               p->sleep_start_fair = lrq->fair_clock;
+               lrq->wait_runtime -= p->wait_runtime;
+       }
+       __dequeue_entity(lrq, p);
+}
+
+/*
+ * Preempt the current task with a newly woken task if needed:
+ */
+static inline void
+__check_preempt_curr_fair(struct lrq *lrq, struct sched_entity *p,
+                         struct sched_entity *curr, unsigned long granularity)
+{
+       s64 __delta = curr->fair_key - p->fair_key;
+
+       /*
+        * Take scheduling granularity into account - do not
+        * preempt the current task unless the best task has
+        * a larger than sched_granularity fairness advantage:
+        */
+       if (__delta > niced_granularity(curr, granularity))
+               resched_task(lrq_rq(lrq)->curr);
+}
+
+static struct sched_entity * pick_next_entity(struct lrq *lrq, u64 now)
+{
+       struct sched_entity *p = __pick_next_entity(lrq);
+
+       /*
+        * Any task has to be enqueued before it get to execute on
+        * a CPU. So account for the time it spent waiting on the
+        * runqueue. (note, here we rely on pick_next_task() having
+        * done a put_prev_task_fair() shortly before this, which
+        * updated rq->fair_clock - used by update_stats_wait_end())
+        */
+       update_stats_wait_end(lrq, p, now);
+       update_stats_curr_start(lrq, p, now);
+
+       return p;
+}
+
+static void put_prev_entity(struct lrq *lrq, struct sched_entity *prev, u64 
now)
+{
+       /*
+        * If the task is still waiting for the CPU (it just got
+        * preempted), update its position within the tree and
+        * start the wait period:
+        */
+       if ((sysctl_sched_features & 16) && entity_is_task(prev))  {
+               struct task_struct *prevtask = entity_to_task(prev);
+
+               if (prev->on_rq &&
+                       test_tsk_thread_flag(prevtask, TIF_NEED_RESCHED)) {
+
+                       dequeue_entity(lrq, prev, 0, now);
+                       prev->on_rq = 0;
+                       enqueue_entity(lrq, prev, 0, now);
+                       prev->on_rq = 1;
+               } else
+                       update_curr(lrq, now);
+       } else {
+               update_curr(lrq, now);
+       }
+
+       update_stats_curr_end(lrq, prev, now);
+
+       if (prev->on_rq)
+               update_stats_wait_start(lrq, prev, now);
+}
+
+static void entity_tick(struct lrq *lrq, struct sched_entity *curr)
+{
+       struct sched_entity *next;
+       struct rq *rq = lrq_rq(lrq);
+       u64 now = __rq_clock(rq);
+
+       /*
+        * Dequeue and enqueue the task to update its
+        * position within the tree:
+        */
+       dequeue_entity(lrq, curr, 0, now);
+       curr->on_rq = 0;
+       enqueue_entity(lrq, curr, 0, now);
+       curr->on_rq = 1;
+
+       /*
+        * Reschedule if another task tops the current one.
+        */
+       next = __pick_next_entity(lrq);
+       if (next == curr)
+               return;
+
+       if (entity_is_task(curr)) {
+               struct task_struct *curtask = entity_to_task(curr),
+                                  *nexttask = entity_to_task(next);
+
+               if ((curtask == rq->idle) || (rt_prio(nexttask->prio) &&
+                                       (nexttask->prio < curtask->prio))) {
+                       resched_task(curtask);
+                       return;
+               }
+       }
+       __check_preempt_curr_fair(lrq, next, curr, sysctl_sched_granularity);
+}
+
+
+/******************************************************************************/
+/*                         BEGIN : CFS operations on tasks                    
*/
+/******************************************************************************/
+
+static inline struct lrq *task_lrq(struct task_struct *p)
+{
+       return &task_rq(p)->lrq;
+}
+
+/*
+ * The enqueue_task method is called before nr_running is
+ * increased. Here we update the fair scheduling stats and
+ * then put the task into the rbtree:
+ */
+static void
+enqueue_task_fair(struct rq *rq, struct task_struct *p, int wakeup, u64 now)
+{
+       struct lrq *lrq = task_lrq(p);
+       struct sched_entity *se = &p->se;
+
+       enqueue_entity(lrq, se, wakeup, now);
 }
 
 /*
@@ -460,16 +637,10 @@
 static void
 dequeue_task_fair(struct rq *rq, struct task_struct *p, int sleep, u64 now)
 {
-       update_stats_dequeue(rq, p, now);
-       if (sleep) {
-               if (p->state & TASK_INTERRUPTIBLE)
-                       p->se.sleep_start = now;
-               if (p->state & TASK_UNINTERRUPTIBLE)
-                       p->se.block_start = now;
-               p->se.sleep_start_fair = rq->lrq.fair_clock;
-               rq->lrq.wait_runtime -= p->se.wait_runtime;
-       }
-       __dequeue_task_fair(rq, p);
+       struct lrq *lrq = task_lrq(p);
+       struct sched_entity *se = &p->se;
+
+       dequeue_entity(lrq, se, sleep, now);
 }
 
 /*
@@ -482,16 +653,18 @@
 {
        struct task_struct *p_next;
        u64 now;
+       struct lrq *lrq = task_lrq(p);
+       struct sched_entity *se = &p->se;
 
        now = __rq_clock(rq);
        /*
         * Dequeue and enqueue the task to update its
         * position within the tree:
         */
-       dequeue_task_fair(rq, p, 0, now);
-       p->se.on_rq = 0;
-       enqueue_task_fair(rq, p, 0, now);
-       p->se.on_rq = 1;
+       dequeue_entity(lrq, se, 0, now);
+       se->on_rq = 0;
+       enqueue_entity(lrq, se, 0, now);
+       se->on_rq = 1;
 
        /*
         * yield-to support: if we are on the same runqueue then
@@ -503,35 +676,19 @@
 
                s64 delta = p->se.wait_runtime >> 1;
 
-               __add_wait_runtime(rq, p_to, delta);
-               __add_wait_runtime(rq, p, -delta);
+               __add_wait_runtime(lrq, &p_to->se, delta);
+               __add_wait_runtime(lrq, &p->se, -delta);
        }
 
        /*
         * Reschedule if another task tops the current one.
         */
-       p_next = __pick_next_task_fair(rq);
+       se = __pick_next_entity(lrq);
+       p_next = entity_to_task(se);
        if (p_next != p)
                resched_task(p);
 }
 
-/*
- * Preempt the current task with a newly woken task if needed:
- */
-static inline void
-__check_preempt_curr_fair(struct rq *rq, struct task_struct *p,
-                         struct task_struct *curr, unsigned long granularity)
-{
-       s64 __delta = curr->se.fair_key - p->se.fair_key;
-
-       /*
-        * Take scheduling granularity into account - do not
-        * preempt the current task unless the best task has
-        * a larger than sched_granularity fairness advantage:
-        */
-       if (__delta > niced_granularity(curr, granularity))
-               resched_task(curr);
-}
 
 /*
  * Preempt the current task with a newly woken task if needed:
@@ -539,12 +696,13 @@
 static void check_preempt_curr_fair(struct rq *rq, struct task_struct *p)
 {
        struct task_struct *curr = rq->curr;
+       struct lrq *lrq = task_lrq(curr);
        unsigned long granularity;
 
        if ((curr == rq->idle) || rt_prio(p->prio)) {
                if (sysctl_sched_features & 8) {
                        if (rt_prio(p->prio))
-                               update_curr(rq, rq_clock(rq));
+                               update_curr(lrq, rq_clock(rq));
                }
                resched_task(curr);
        } else {
@@ -555,25 +713,18 @@
                if (unlikely(p->policy == SCHED_BATCH))
                        granularity = sysctl_sched_batch_wakeup_granularity;
 
-               __check_preempt_curr_fair(rq, p, curr, granularity);
+               __check_preempt_curr_fair(lrq, &p->se, &curr->se, granularity);
        }
 }
 
 static struct task_struct * pick_next_task_fair(struct rq *rq, u64 now)
 {
-       struct task_struct *p = __pick_next_task_fair(rq);
+       struct lrq *lrq = &rq->lrq;
+       struct sched_entity *se;
 
-       /*
-        * Any task has to be enqueued before it get to execute on
-        * a CPU. So account for the time it spent waiting on the
-        * runqueue. (note, here we rely on pick_next_task() having
-        * done a put_prev_task_fair() shortly before this, which
-        * updated rq->fair_clock - used by update_stats_wait_end())
-        */
-       update_stats_wait_end(rq, p, now);
-       update_stats_curr_start(rq, p, now);
+       se = pick_next_entity(lrq, now);
 
-       return p;
+       return entity_to_task(se);
 }
 
 /*
@@ -581,32 +732,13 @@
  */
 static void put_prev_task_fair(struct rq *rq, struct task_struct *prev, u64 
now)
 {
+       struct lrq *lrq = task_lrq(prev);
+       struct sched_entity *se = &prev->se;
+
        if (prev == rq->idle)
                return;
 
-       /*
-        * If the task is still waiting for the CPU (it just got
-        * preempted), update its position within the tree and
-        * start the wait period:
-        */
-       if (sysctl_sched_features & 16)  {
-               if (prev->se.on_rq &&
-                       test_tsk_thread_flag(prev, TIF_NEED_RESCHED)) {
-
-                       dequeue_task_fair(rq, prev, 0, now);
-                       prev->se.on_rq = 0;
-                       enqueue_task_fair(rq, prev, 0, now);
-                       prev->se.on_rq = 1;
-               } else
-                       update_curr(rq, now);
-       } else {
-               update_curr(rq, now);
-       }
-
-       update_stats_curr_end(rq, prev, now);
-
-       if (prev->se.on_rq)
-               update_stats_wait_start(rq, prev, now);
+       put_prev_entity(lrq, se, now);
 }
 
 /**************************************************************/
@@ -636,7 +768,7 @@
 
 static struct task_struct * load_balance_start_fair(struct rq *rq)
 {
-       return __load_balance_iterator(rq, first_fair(rq));
+       return __load_balance_iterator(rq, first_fair(&rq->lrq));
 }
 
 static struct task_struct * load_balance_next_fair(struct rq *rq)
@@ -649,31 +781,10 @@
  */
 static void task_tick_fair(struct rq *rq, struct task_struct *curr)
 {
-       struct task_struct *next;
-       u64 now = __rq_clock(rq);
-
-       /*
-        * Dequeue and enqueue the task to update its
-        * position within the tree:
-        */
-       dequeue_task_fair(rq, curr, 0, now);
-       curr->se.on_rq = 0;
-       enqueue_task_fair(rq, curr, 0, now);
-       curr->se.on_rq = 1;
-
-       /*
-        * Reschedule if another task tops the current one.
-        */
-       next = __pick_next_task_fair(rq);
-       if (next == curr)
-               return;
+       struct lrq *lrq = task_lrq(curr);
+       struct sched_entity *se = &curr->se;
 
-       if ((curr == rq->idle) || (rt_prio(next->prio) &&
-                                       (next->prio < curr->prio)))
-               resched_task(curr);
-       else
-               __check_preempt_curr_fair(rq, next, curr,
-                                         sysctl_sched_granularity);
+       entity_tick(lrq, se);
 }
 
 /*
@@ -685,14 +796,17 @@
  */
 static void task_new_fair(struct rq *rq, struct task_struct *p)
 {
+       struct lrq *lrq = task_lrq(p);
+       struct sched_entity *se = &p->se;
+
        sched_info_queued(p);
-       update_stats_enqueue(rq, p, rq_clock(rq));
+       update_stats_enqueue(lrq, se, rq_clock(rq));
        /*
         * Child runs first: we let it run before the parent
         * until it reschedules once. We set up the key so that
         * it will preempt the parent:
         */
-       p->se.fair_key = current->se.fair_key - niced_granularity(rq->curr,
+       p->se.fair_key = current->se.fair_key - niced_granularity(&rq->curr->se,
                                                sysctl_sched_granularity) - 1;
        /*
         * The first wait is dominated by the child-runs-first logic,
@@ -706,7 +820,7 @@
         */
 //     p->se.wait_runtime = -(s64)(sysctl_sched_granularity / 2);
 
-       __enqueue_task_fair(rq, p);
+       __enqueue_entity(lrq, se);
        p->se.on_rq = 1;
        inc_nr_running(p, rq);
 }
Index: current/kernel/sched_debug.c
===================================================================
--- current.orig/kernel/sched_debug.c   2007-06-09 15:07:16.000000000 +0530
+++ current/kernel/sched_debug.c        2007-06-09 15:07:33.000000000 +0530
@@ -87,7 +87,7 @@
        unsigned long flags;
 
        spin_lock_irqsave(&rq->lock, flags);
-       curr = first_fair(rq);
+       curr = first_fair(&rq->lrq);
        while (curr) {
                p = rb_entry(curr, struct task_struct, se.run_node);
                wait_runtime_rq_sum += p->se.wait_runtime;
-- 
Regards,
vatsa
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