Prepare k-FMLP for integration with Linux 3.0

Also added k-fmlp support to CEDF.

2 files changed, 590 insertions, 49 deletions

diff --git a/litmus/sched_cedf.c b/litmus/sched_cedf.c
index 73fe1c442a0d..5e977dd2fef0 100644
--- a/litmus/sched_cedf.c
+++ b/litmus/sched_cedf.c
@@ -29,6 +29,7 @@
 #include <linux/percpu.h>
 #include <linux/sched.h>
 #include <linux/slab.h>
+#include <linux/uaccess.h>
 
 #include <linux/module.h>
 
@@ -45,7 +46,6 @@
 
 /* to configure the cluster size */
 #include <litmus/litmus_proc.h>
-#include <linux/uaccess.h>
 
 /* Reference configuration variable. Determines which cache level is used to
  * group CPUs into clusters.  GLOBAL_CLUSTER, which is the default, means that
@@ -95,7 +95,7 @@ typedef struct clusterdomain {
         struct bheap_node *heap_node;
         struct bheap      cpu_heap;
         /* lock for this cluster */
-#define lock domain.ready_lock
+#define cedf_lock domain.ready_lock
 } cedf_domain_t;
 
 /* a cedf_domain per cluster; allocation is done at init/activation time */
@@ -292,12 +292,12 @@ static void cedf_release_jobs(rt_domain_t* rt, struct bheap* tasks)
         cedf_domain_t* cluster = container_of(rt, cedf_domain_t, domain);
         unsigned long flags;
 
-        raw_spin_lock_irqsave(&cluster->lock, flags);
+        raw_spin_lock_irqsave(&cluster->cedf_lock, flags);
 
         __merge_ready(&cluster->domain, tasks);
         check_for_preemptions(cluster);
 
-        raw_spin_unlock_irqrestore(&cluster->lock, flags);
+        raw_spin_unlock_irqrestore(&cluster->cedf_lock, flags);
 }
 
 /* caller holds cedf_lock */
@@ -378,7 +378,7 @@ static struct task_struct* cedf_schedule(struct task_struct * prev)
         int out_of_time, sleep, preempt, np, exists, blocks;
         struct task_struct* next = NULL;
 
-        raw_spin_lock(&cluster->lock);
+        raw_spin_lock(&cluster->cedf_lock);
         clear_will_schedule();
 
         /* sanity checking */
@@ -462,7 +462,7 @@ static struct task_struct* cedf_schedule(struct task_struct * prev)
                         next = prev;
 
         sched_state_task_picked();
-        raw_spin_unlock(&cluster->lock);
+        raw_spin_unlock(&cluster->cedf_lock);
 
 #ifdef WANT_ALL_SCHED_EVENTS
         TRACE("cedf_lock released, next=0x%p\n", next);
@@ -504,7 +504,7 @@ static void cedf_task_new(struct task_struct * t, int on_rq, int running)
         /* the cluster doesn't change even if t is running */
         cluster = task_cpu_cluster(t);
 
-        raw_spin_lock_irqsave(&cluster->domain.ready_lock, flags);
+        raw_spin_lock_irqsave(&cluster->cedf_lock, flags);
 
         /* setup job params */
         release_at(t, litmus_clock());
@@ -521,7 +521,7 @@ static void cedf_task_new(struct task_struct * t, int on_rq, int running)
         t->rt_param.linked_on          = NO_CPU;
 
         cedf_job_arrival(t);
-        raw_spin_unlock_irqrestore(&(cluster->domain.ready_lock), flags);
+        raw_spin_unlock_irqrestore(&(cluster->cedf_lock), flags);
 }
 
 static void cedf_task_wake_up(struct task_struct *task)
@@ -534,7 +534,7 @@ static void cedf_task_wake_up(struct task_struct *task)
 
         cluster = task_cpu_cluster(task);
 
-        raw_spin_lock_irqsave(&cluster->lock, flags);
+        raw_spin_lock_irqsave(&cluster->cedf_lock, flags);
         /* We need to take suspensions because of semaphores into
          * account! If a job resumes after being suspended due to acquiring
          * a semaphore, it should never be treated as a new job release.
@@ -557,7 +557,7 @@ static void cedf_task_wake_up(struct task_struct *task)
                 }
         }
         cedf_job_arrival(task);
-        raw_spin_unlock_irqrestore(&cluster->lock, flags);
+        raw_spin_unlock_irqrestore(&cluster->cedf_lock, flags);
 }
 
 static void cedf_task_block(struct task_struct *t)
@@ -570,9 +570,9 @@ static void cedf_task_block(struct task_struct *t)
         cluster = task_cpu_cluster(t);
 
         /* unlink if necessary */
-        raw_spin_lock_irqsave(&cluster->lock, flags);
+        raw_spin_lock_irqsave(&cluster->cedf_lock, flags);
         unlink(t);
-        raw_spin_unlock_irqrestore(&cluster->lock, flags);
+        raw_spin_unlock_irqrestore(&cluster->cedf_lock, flags);
 
         BUG_ON(!is_realtime(t));
 }
@@ -584,7 +584,7 @@ static void cedf_task_exit(struct task_struct * t)
         cedf_domain_t *cluster = task_cpu_cluster(t);
 
         /* unlink if necessary */
-        raw_spin_lock_irqsave(&cluster->lock, flags);
+        raw_spin_lock_irqsave(&cluster->cedf_lock, flags);
         unlink(t);
         if (tsk_rt(t)->scheduled_on != NO_CPU) {
                 cpu_entry_t *cpu;
@@ -592,7 +592,7 @@ static void cedf_task_exit(struct task_struct * t)
                 cpu->scheduled = NULL;
                 tsk_rt(t)->scheduled_on = NO_CPU;
         }
-        raw_spin_unlock_irqrestore(&cluster->lock, flags);
+        raw_spin_unlock_irqrestore(&cluster->cedf_lock, flags);
 
         BUG_ON(!is_realtime(t));
         TRACE_TASK(t, "RIP\n");
@@ -603,6 +603,578 @@ static long cedf_admit_task(struct task_struct* tsk)
         return task_cpu(tsk) == tsk->rt_param.task_params.cpu ? 0 : -EINVAL;
 }
 
+
+
+
+
+
+
+
+
+
+
+
+
+#ifdef CONFIG_LITMUS_LOCKING
+
+#include <litmus/fdso.h>
+
+
+static void __set_priority_inheritance(struct task_struct* t, struct task_struct* prio_inh)
+{
+        int linked_on;
+        int check_preempt = 0;  
+        
+        cedf_domain_t* cluster = task_cpu_cluster(t);
+        
+        if(prio_inh != NULL)
+                TRACE_TASK(t, "inherits priority from %s/%d\n", prio_inh->comm, prio_inh->pid);
+        else
+                TRACE_TASK(t, "inherits priority from %p\n", prio_inh);
+        
+        //sched_trace_eff_prio_change(t, prio_inh);
+        
+        tsk_rt(t)->inh_task = prio_inh;
+        
+        linked_on  = tsk_rt(t)->linked_on;
+        
+        /* If it is scheduled, then we need to reorder the CPU heap. */
+        if (linked_on != NO_CPU) {
+                TRACE_TASK(t, "%s: linked  on %d\n",
+                                   __FUNCTION__, linked_on);
+                /* Holder is scheduled; need to re-order CPUs.
+                 * We can't use heap_decrease() here since
+                 * the cpu_heap is ordered in reverse direction, so
+                 * it is actually an increase. */
+                bheap_delete(cpu_lower_prio, &cluster->cpu_heap,
+                     per_cpu(cedf_cpu_entries, linked_on).hn);
+                bheap_insert(cpu_lower_prio, &cluster->cpu_heap,
+                     per_cpu(cedf_cpu_entries, linked_on).hn);
+        } else {
+                /* holder may be queued: first stop queue changes */
+                raw_spin_lock(&cluster->domain.release_lock);
+                if (is_queued(t)) {
+                        TRACE_TASK(t, "%s: is queued\n", __FUNCTION__);
+                        
+                        /* We need to update the position of holder in some
+                         * heap. Note that this could be a release heap if we
+                         * budget enforcement is used and this job overran. */
+                        check_preempt = !bheap_decrease(edf_ready_order, tsk_rt(t)->heap_node);
+                        
+                } else {
+                        /* Nothing to do: if it is not queued and not linked
+                         * then it is either sleeping or currently being moved
+                         * by other code (e.g., a timer interrupt handler) that
+                         * will use the correct priority when enqueuing the
+                         * task. */
+                        TRACE_TASK(t, "%s: is NOT queued => Done.\n", __FUNCTION__);
+                }
+                raw_spin_unlock(&cluster->domain.release_lock);
+                
+                /* If holder was enqueued in a release heap, then the following
+                 * preemption check is pointless, but we can't easily detect
+                 * that case. If you want to fix this, then consider that
+                 * simply adding a state flag requires O(n) time to update when
+                 * releasing n tasks, which conflicts with the goal to have
+                 * O(log n) merges. */
+                if (check_preempt) {
+                        /* heap_decrease() hit the top level of the heap: make
+                         * sure preemption checks get the right task, not the
+                         * potentially stale cache. */
+                        bheap_uncache_min(edf_ready_order, &cluster->domain.ready_queue);
+                        check_for_preemptions(cluster);
+                }
+        }
+}
+
+/* called with IRQs off */
+static void set_priority_inheritance(struct task_struct* t, struct task_struct* prio_inh)
+{
+        cedf_domain_t* cluster = task_cpu_cluster(t);
+        
+        raw_spin_lock(&cluster->cedf_lock);
+        
+        __set_priority_inheritance(t, prio_inh);
+
+        raw_spin_unlock(&cluster->cedf_lock);
+}
+
+
+/* called with IRQs off */
+static void __clear_priority_inheritance(struct task_struct* t)
+{
+    TRACE_TASK(t, "priority restored\n");
+        
+    if(tsk_rt(t)->scheduled_on != NO_CPU)
+    {
+                //sched_trace_eff_prio_change(t, NULL);
+                
+        tsk_rt(t)->inh_task = NULL;
+        
+        /* Check if rescheduling is necessary. We can't use heap_decrease()
+         * since the priority was effectively lowered. */
+        unlink(t);
+        cedf_job_arrival(t);
+    }
+    else
+    {
+        __set_priority_inheritance(t, NULL);
+    }
+}
+
+/* called with IRQs off */
+static void clear_priority_inheritance(struct task_struct* t)
+{
+        cedf_domain_t* cluster = task_cpu_cluster(t);
+        
+        raw_spin_lock(&cluster->cedf_lock);
+        __clear_priority_inheritance(t);
+        raw_spin_unlock(&cluster->cedf_lock);
+}
+
+
+
+/* ******************** KFMLP support ********************** */
+
+/* struct for semaphore with priority inheritance */
+struct kfmlp_queue
+{
+        wait_queue_head_t wait;
+        struct task_struct* owner;
+        struct task_struct* hp_waiter;
+        int count; /* number of waiters + holder */
+};
+
+struct kfmlp_semaphore
+{
+        struct litmus_lock litmus_lock;
+        
+        spinlock_t lock;
+        
+        int num_resources; /* aka k */
+        struct kfmlp_queue *queues; /* array */
+        struct kfmlp_queue *shortest_queue; /* pointer to shortest queue */
+};
+
+static inline struct kfmlp_semaphore* kfmlp_from_lock(struct litmus_lock* lock)
+{
+        return container_of(lock, struct kfmlp_semaphore, litmus_lock);
+}
+
+static inline int kfmlp_get_idx(struct kfmlp_semaphore* sem,
+                                                                struct kfmlp_queue* queue)
+{
+        return (queue - &sem->queues[0]);
+}
+
+static inline struct kfmlp_queue* kfmlp_get_queue(struct kfmlp_semaphore* sem,
+                                                                                                  struct task_struct* holder)
+{
+        int i;
+        for(i = 0; i < sem->num_resources; ++i)
+                if(sem->queues[i].owner == holder)
+                        return(&sem->queues[i]);
+        return(NULL);
+}
+
+/* caller is responsible for locking */
+static struct task_struct* kfmlp_find_hp_waiter(struct kfmlp_queue *kqueue,
+                                                                                 struct task_struct *skip)
+{
+        struct list_head        *pos;
+        struct task_struct      *queued, *found = NULL;
+        
+        list_for_each(pos, &kqueue->wait.task_list) {
+                queued  = (struct task_struct*) list_entry(pos, wait_queue_t,
+                                                                                                   task_list)->private;
+                
+                /* Compare task prios, find high prio task. */
+                if (queued != skip && edf_higher_prio(queued, found))
+                        found = queued;
+        }
+        return found;
+}
+
+static inline struct kfmlp_queue* kfmlp_find_shortest(
+                                                                                  struct kfmlp_semaphore* sem,
+                                                                                  struct kfmlp_queue* search_start)
+{
+        // we start our search at search_start instead of at the beginning of the
+        // queue list to load-balance across all resources.
+        struct kfmlp_queue* step = search_start;
+        struct kfmlp_queue* shortest = sem->shortest_queue;
+        
+        do
+        {
+                step = (step+1 != &sem->queues[sem->num_resources]) ?
+                step+1 : &sem->queues[0];
+                if(step->count < shortest->count)
+                {
+                        shortest = step;
+                        if(step->count == 0)
+                                break; /* can't get any shorter */
+                }
+        }while(step != search_start);
+        
+        return(shortest);
+}
+
+static struct task_struct* kfmlp_remove_hp_waiter(struct kfmlp_semaphore* sem)
+{
+        /* must hold sem->lock */
+        
+        struct kfmlp_queue *my_queue = NULL;
+        struct task_struct *max_hp = NULL;
+        
+        
+        struct list_head        *pos;
+        struct task_struct      *queued;
+        int i;
+        
+        for(i = 0; i < sem->num_resources; ++i)
+        {
+                if( (sem->queues[i].count > 1) &&
+                   ((my_queue == NULL) ||
+                        (edf_higher_prio(sem->queues[i].hp_waiter, my_queue->hp_waiter))) )
+                {
+                        my_queue = &sem->queues[i];
+                }
+        }
+        
+        if(my_queue)
+        {
+                cedf_domain_t* cluster;
+                
+                max_hp = my_queue->hp_waiter;
+                BUG_ON(!max_hp);
+
+                TRACE_CUR("queue %d: stealing %s/%d from queue %d\n",
+                                  kfmlp_get_idx(sem, my_queue),
+                                  max_hp->comm, max_hp->pid,
+                                  kfmlp_get_idx(sem, my_queue));
+                
+                my_queue->hp_waiter = kfmlp_find_hp_waiter(my_queue, max_hp);
+        
+                cluster = task_cpu_cluster(max_hp);
+
+                raw_spin_lock(&cluster->cedf_lock);
+                
+                if(tsk_rt(my_queue->owner)->inh_task == max_hp)
+                {
+                        __clear_priority_inheritance(my_queue->owner);
+                        if(my_queue->hp_waiter != NULL)
+                        {
+                                __set_priority_inheritance(my_queue->owner, my_queue->hp_waiter);
+                        }
+                }
+                raw_spin_unlock(&cluster->cedf_lock);
+                
+                list_for_each(pos, &my_queue->wait.task_list)
+                {
+                        queued  = (struct task_struct*) list_entry(pos, wait_queue_t,
+                                                                                                           task_list)->private;
+                        /* Compare task prios, find high prio task. */
+                        if (queued == max_hp)
+                        {
+                                __remove_wait_queue(&my_queue->wait,
+                                                                        list_entry(pos, wait_queue_t, task_list));
+                                break;
+                        }
+                }
+                --(my_queue->count);
+        }
+        
+        return(max_hp);
+}
+
+int cedf_kfmlp_lock(struct litmus_lock* l)
+{
+        struct task_struct* t = current;
+        struct kfmlp_semaphore *sem = kfmlp_from_lock(l);
+        struct kfmlp_queue* my_queue;
+        wait_queue_t wait;
+        unsigned long flags;
+        
+        if (!is_realtime(t))
+                return -EPERM;
+        
+        spin_lock_irqsave(&sem->lock, flags);
+        
+        my_queue = sem->shortest_queue;
+        
+        if (my_queue->owner) {
+                /* resource is not free => must suspend and wait */
+                TRACE_CUR("queue %d: Resource is not free => must suspend and wait.\n",
+                                  kfmlp_get_idx(sem, my_queue));
+                
+                init_waitqueue_entry(&wait, t);
+                
+                /* FIXME: interruptible would be nice some day */
+                set_task_state(t, TASK_UNINTERRUPTIBLE);
+                
+                __add_wait_queue_tail_exclusive(&my_queue->wait, &wait);
+                
+                /* check if we need to activate priority inheritance */
+                if (edf_higher_prio(t, my_queue->hp_waiter))
+                {
+                        my_queue->hp_waiter = t;
+                        if (edf_higher_prio(t, my_queue->owner))
+                        {
+                                set_priority_inheritance(my_queue->owner, my_queue->hp_waiter);
+                        }
+                }
+                
+                ++(my_queue->count);
+                sem->shortest_queue = kfmlp_find_shortest(sem, my_queue);
+                
+                /* release lock before sleeping */
+                spin_unlock_irqrestore(&sem->lock, flags);
+                
+                /* We depend on the FIFO order.  Thus, we don't need to recheck
+                 * when we wake up; we are guaranteed to have the lock since
+                 * there is only one wake up per release (or steal).
+                 */
+                schedule();
+                
+                
+                if(my_queue->owner == t)
+                {
+                        TRACE_CUR("queue %d: acquired through waiting\n",
+                                          kfmlp_get_idx(sem, my_queue));
+                }
+                else
+                {
+                        /* this case may happen if our wait entry was stolen
+                         between queues.  record where we went.*/
+                        my_queue = kfmlp_get_queue(sem, t);
+                        BUG_ON(!my_queue);
+                        TRACE_CUR("queue %d: acquired through stealing\n",
+                                          kfmlp_get_idx(sem, my_queue));
+                }
+        }
+        else
+        {
+                TRACE_CUR("queue %d: acquired immediately\n",
+                                  kfmlp_get_idx(sem, my_queue));
+                
+                my_queue->owner = t;
+                
+                ++(my_queue->count);
+                sem->shortest_queue = kfmlp_find_shortest(sem, my_queue);               
+                
+                spin_unlock_irqrestore(&sem->lock, flags);
+        }
+        
+        return kfmlp_get_idx(sem, my_queue);
+}
+
+int cedf_kfmlp_unlock(struct litmus_lock* l)
+{
+        struct task_struct *t = current, *next;
+        struct kfmlp_semaphore *sem = kfmlp_from_lock(l);
+        struct kfmlp_queue *my_queue;
+        unsigned long flags;
+        int err = 0;
+        
+        spin_lock_irqsave(&sem->lock, flags);
+        
+        my_queue = kfmlp_get_queue(sem, t);
+        
+        if (!my_queue) {
+                err = -EINVAL;
+                goto out;
+        }
+        
+        /* check if there are jobs waiting for this resource */
+        next = __waitqueue_remove_first(&my_queue->wait);
+        if (next) {
+                /* next becomes the resouce holder */
+                my_queue->owner = next;
+                
+                --(my_queue->count);
+                if(my_queue->count < sem->shortest_queue->count)
+                {
+                        sem->shortest_queue = my_queue;
+                }       
+                
+                TRACE_CUR("queue %d: lock ownership passed to %s/%d\n",
+                                  kfmlp_get_idx(sem, my_queue), next->comm, next->pid);
+                
+                /* determine new hp_waiter if necessary */
+                if (next == my_queue->hp_waiter) {
+                        TRACE_TASK(next, "was highest-prio waiter\n");
+                        /* next has the highest priority --- it doesn't need to
+                         * inherit.  However, we need to make sure that the
+                         * next-highest priority in the queue is reflected in
+                         * hp_waiter. */
+                        my_queue->hp_waiter = kfmlp_find_hp_waiter(my_queue, next);
+                        if (my_queue->hp_waiter)
+                                TRACE_TASK(my_queue->hp_waiter, "queue %d: is new highest-prio waiter\n", kfmlp_get_idx(sem, my_queue));
+                        else
+                                TRACE("queue %d: no further waiters\n", kfmlp_get_idx(sem, my_queue));
+                } else {
+                        /* Well, if next is not the highest-priority waiter,
+                         * then it ought to inherit the highest-priority
+                         * waiter's priority. */
+                        set_priority_inheritance(next, my_queue->hp_waiter);
+                }
+                
+                /* wake up next */
+                wake_up_process(next);
+        }
+        else
+        {
+                TRACE_CUR("queue %d: looking to steal someone...\n", kfmlp_get_idx(sem, my_queue));
+                
+                next = kfmlp_remove_hp_waiter(sem); /* returns NULL if nothing to steal */
+                
+                my_queue->owner = next;
+                
+                if(next)
+                {
+                        TRACE_CUR("queue %d: lock ownership passed to %s/%d (which was stolen)\n",
+                                          kfmlp_get_idx(sem, my_queue),
+                                          next->comm, next->pid);
+                        
+                        /* wake up next */
+                        wake_up_process(next);                  
+                }
+                else
+                {
+                        TRACE_CUR("queue %d: no one to steal.\n", kfmlp_get_idx(sem, my_queue));
+                        
+                        --(my_queue->count);
+                        if(my_queue->count < sem->shortest_queue->count)
+                        {
+                                sem->shortest_queue = my_queue;
+                        }
+                }
+        }
+        
+        /* we lose the benefit of priority inheritance (if any) */
+        if (tsk_rt(t)->inh_task)
+                clear_priority_inheritance(t);
+        
+out:
+        spin_unlock_irqrestore(&sem->lock, flags);
+        
+        return err;
+}
+
+int cedf_kfmlp_close(struct litmus_lock* l)
+{
+        struct task_struct *t = current;
+        struct kfmlp_semaphore *sem = kfmlp_from_lock(l);
+        struct kfmlp_queue *my_queue;
+        unsigned long flags;
+        
+        int owner;
+        
+        spin_lock_irqsave(&sem->lock, flags);
+        
+        my_queue = kfmlp_get_queue(sem, t);     
+        owner = (my_queue) ? (my_queue->owner == t) : 0;
+        
+        spin_unlock_irqrestore(&sem->lock, flags);
+        
+        if (owner)
+                cedf_kfmlp_unlock(l);
+        
+        return 0;
+}
+
+void cedf_kfmlp_free(struct litmus_lock* l)
+{
+        struct kfmlp_semaphore *sem = kfmlp_from_lock(l);
+        kfree(sem->queues);
+        kfree(sem);
+}
+
+static struct litmus_lock_ops cedf_kfmlp_lock_ops = {
+        .close  = cedf_kfmlp_close,
+        .lock   = cedf_kfmlp_lock,
+        .unlock = cedf_kfmlp_unlock,
+        .deallocate = cedf_kfmlp_free,
+};
+
+static struct litmus_lock* cedf_new_kfmlp(void* __user arg, int* ret_code)
+{
+        struct kfmlp_semaphore* sem;
+        int num_resources = 0;
+        int i;
+        
+        if(!access_ok(VERIFY_READ, arg, sizeof(num_resources)))
+        {
+                *ret_code = -EINVAL;
+                return(NULL);
+        }
+        if(__copy_from_user(&num_resources, arg, sizeof(num_resources)))
+        {
+                *ret_code = -EINVAL;
+                return(NULL);
+        }
+        if(num_resources < 1)
+        {
+                *ret_code = -EINVAL;
+                return(NULL);           
+        }
+        
+        sem = kmalloc(sizeof(*sem), GFP_KERNEL);
+        if(!sem)
+        {
+                *ret_code = -ENOMEM;
+                return NULL;
+        }
+        
+        sem->queues = kmalloc(sizeof(struct kfmlp_queue)*num_resources, GFP_KERNEL);
+        if(!sem->queues)
+        {
+                kfree(sem);
+                *ret_code = -ENOMEM;
+                return NULL;            
+        }
+        
+        sem->litmus_lock.ops = &cedf_kfmlp_lock_ops;
+        spin_lock_init(&sem->lock);
+        sem->num_resources = num_resources;
+        
+        for(i = 0; i < num_resources; ++i)
+        {
+                sem->queues[i].owner = NULL;
+                sem->queues[i].hp_waiter = NULL;
+                init_waitqueue_head(&sem->queues[i].wait);
+                sem->queues[i].count = 0;
+        }
+        
+        sem->shortest_queue = &sem->queues[0];
+        
+        *ret_code = 0;
+        return &sem->litmus_lock;
+}
+
+
+/* **** lock constructor **** */
+
+static long cedf_allocate_lock(struct litmus_lock **lock, int type,
+                                                                 void* __user arg)
+{
+        int err = -ENXIO;
+        
+        /* C-EDF currently only supports the FMLP for global resources
+                WITHIN a given cluster.  DO NOT USE CROSS-CLUSTER! */
+        switch (type) {
+                case KFMLP_SEM:
+                        *lock = cedf_new_kfmlp(arg, &err);
+                        break;
+        };
+        
+        return err;
+}
+
+#endif  // CONFIG_LITMUS_LOCKING
+
+
+
 /* total number of cluster */
 static int num_clusters;
 /* we do not support cluster of different sizes */
@@ -765,6 +1337,9 @@ static struct sched_plugin cedf_plugin __cacheline_aligned_in_smp = {
         .task_block             = cedf_task_block,
         .admit_task             = cedf_admit_task,
         .activate_plugin        = cedf_activate_plugin,
+#ifdef CONFIG_LITMUS_LOCKING
+        .allocate_lock  = cedf_allocate_lock,
+#endif
 };
 
 static struct proc_dir_entry *cluster_file = NULL, *cedf_dir = NULL;
diff --git a/litmus/sched_gsn_edf.c b/litmus/sched_gsn_edf.c
index bf8d989f1c4a..b87524cf1802 100644
--- a/litmus/sched_gsn_edf.c
+++ b/litmus/sched_gsn_edf.c
@@ -935,7 +935,6 @@ struct kfmlp_semaphore
         spinlock_t      lock;
         
         int num_resources; /* aka k */
-        
         struct kfmlp_queue *queues; /* array */
         struct kfmlp_queue *shortest_queue; /* pointer to shortest queue */
 };
@@ -992,6 +991,7 @@ static inline struct kfmlp_queue* kfmlp_find_shortest(
         {
                 step = (step+1 != &sem->queues[sem->num_resources]) ?
                         step+1 : &sem->queues[0];
+
                 if(step->count < shortest->count)
                 {
                         shortest = step;
@@ -1038,31 +1038,8 @@ struct task_struct* kfmlp_remove_hp_waiter(struct kfmlp_semaphore* sem)
                 
                 my_queue->hp_waiter = kfmlp_find_hp_waiter(my_queue, max_hp);
                 
-                /*
-                if(my_queue->hp_waiter)
-                        TRACE_CUR("queue %d: new hp_waiter is %s/%d\n",
-                                          kfmlp_get_idx(sem, my_queue),
-                                          my_queue->hp_waiter->comm,
-                                          my_queue->hp_waiter->pid);
-                else
-                        TRACE_CUR("queue %d: new hp_waiter is %p\n",
-                                          kfmlp_get_idx(sem, my_queue), NULL);
-                 */
-                
                 raw_spin_lock(&gsnedf_lock);
                 
-                /*
-                if(my_queue->owner)
-                        TRACE_CUR("queue %d: owner is %s/%d\n",
-                                          kfmlp_get_idx(sem, my_queue),
-                                          my_queue->owner->comm,
-                                          my_queue->owner->pid);
-                else
-                        TRACE_CUR("queue %d: owner is %p\n",
-                                          kfmlp_get_idx(sem, my_queue),
-                                          NULL);
-                 */
-                
                 if(tsk_rt(my_queue->owner)->inh_task == max_hp)
                 {
                         __clear_priority_inheritance(my_queue->owner);
@@ -1080,10 +1057,6 @@ struct task_struct* kfmlp_remove_hp_waiter(struct kfmlp_semaphore* sem)
                         /* Compare task prios, find high prio task. */
                         if (queued == max_hp)
                         {
-                                /*
-                                TRACE_CUR("queue %d: found entry in wait queue.  REMOVING!\n",
-                                                  kfmlp_get_idx(sem, my_queue));
-                                */
                                 __remove_wait_queue(&my_queue->wait,
                                                                         list_entry(pos, wait_queue_t, task_list));
                                 break;
@@ -1240,13 +1213,6 @@ int gsnedf_kfmlp_unlock(struct litmus_lock* l)
                 
                 next = kfmlp_remove_hp_waiter(sem); /* returns NULL if nothing to steal */
 
-                /*
-                if(next)
-                        TRACE_CUR("queue %d: ASSIGNING %s/%d as owner - steal\n",
-                                          kfmlp_get_idx(sem, my_queue),
-                                          next->comm, next->pid);
-                */
-                
                 my_queue->owner = next;
                 
                 if(next)