Merge branch 'linux-2.6'
[pandora-kernel.git] / arch / powerpc / platforms / cell / spufs / sched.c
index 9ad53e6..00d9142 100644 (file)
@@ -58,6 +58,7 @@ static unsigned long spu_avenrun[3];
 static struct spu_prio_array *spu_prio;
 static struct task_struct *spusched_task;
 static struct timer_list spusched_timer;
+static struct timer_list spuloadavg_timer;
 
 /*
  * Priority of a normal, non-rt, non-niced'd process (aka nice level 0).
@@ -105,15 +106,21 @@ void spu_set_timeslice(struct spu_context *ctx)
 void __spu_update_sched_info(struct spu_context *ctx)
 {
        /*
-        * 32-Bit assignment are atomic on powerpc, and we don't care about
-        * memory ordering here because retriving the controlling thread is
-        * per defintion racy.
+        * assert that the context is not on the runqueue, so it is safe
+        * to change its scheduling parameters.
+        */
+       BUG_ON(!list_empty(&ctx->rq));
+
+       /*
+        * 32-Bit assignments are atomic on powerpc, and we don't care about
+        * memory ordering here because retrieving the controlling thread is
+        * per definition racy.
         */
        ctx->tid = current->pid;
 
        /*
         * We do our own priority calculations, so we normally want
-        * ->static_prio to start with. Unfortunately thies field
+        * ->static_prio to start with. Unfortunately this field
         * contains junk for threads with a realtime scheduling
         * policy so we have to look at ->prio in this case.
         */
@@ -124,23 +131,32 @@ void __spu_update_sched_info(struct spu_context *ctx)
        ctx->policy = current->policy;
 
        /*
-        * A lot of places that don't hold list_mutex poke into
-        * cpus_allowed, including grab_runnable_context which
-        * already holds the runq_lock.  So abuse runq_lock
-        * to protect this field aswell.
+        * TO DO: the context may be loaded, so we may need to activate
+        * it again on a different node. But it shouldn't hurt anything
+        * to update its parameters, because we know that the scheduler
+        * is not actively looking at this field, since it is not on the
+        * runqueue. The context will be rescheduled on the proper node
+        * if it is timesliced or preempted.
         */
-       spin_lock(&spu_prio->runq_lock);
        ctx->cpus_allowed = current->cpus_allowed;
-       spin_unlock(&spu_prio->runq_lock);
 }
 
 void spu_update_sched_info(struct spu_context *ctx)
 {
-       int node = ctx->spu->node;
+       int node;
 
-       mutex_lock(&cbe_spu_info[node].list_mutex);
-       __spu_update_sched_info(ctx);
-       mutex_unlock(&cbe_spu_info[node].list_mutex);
+       if (ctx->state == SPU_STATE_RUNNABLE) {
+               node = ctx->spu->node;
+
+               /*
+                * Take list_mutex to sync with find_victim().
+                */
+               mutex_lock(&cbe_spu_info[node].list_mutex);
+               __spu_update_sched_info(ctx);
+               mutex_unlock(&cbe_spu_info[node].list_mutex);
+       } else {
+               __spu_update_sched_info(ctx);
+       }
 }
 
 static int __node_allowed(struct spu_context *ctx, int node)
@@ -174,7 +190,7 @@ void do_notify_spus_active(void)
         * Wake up the active spu_contexts.
         *
         * When the awakened processes see their "notify_active" flag is set,
-        * they will call spu_switch_notify();
+        * they will call spu_switch_notify().
         */
        for_each_online_node(node) {
                struct spu *spu;
@@ -221,7 +237,6 @@ static void spu_bind_context(struct spu *spu, struct spu_context *ctx)
        spu->wbox_callback = spufs_wbox_callback;
        spu->stop_callback = spufs_stop_callback;
        spu->mfc_callback = spufs_mfc_callback;
-       spu->dma_callback = spufs_dma_callback;
        mb();
        spu_unmap_mappings(ctx);
        spu_restore(&ctx->csa, spu);
@@ -409,7 +424,6 @@ static void spu_unbind_context(struct spu *spu, struct spu_context *ctx)
        spu->wbox_callback = NULL;
        spu->stop_callback = NULL;
        spu->mfc_callback = NULL;
-       spu->dma_callback = NULL;
        spu_associate_mm(spu, NULL);
        spu->pid = 0;
        spu->tgid = 0;
@@ -454,6 +468,13 @@ static void __spu_add_to_rq(struct spu_context *ctx)
        }
 }
 
+static void spu_add_to_rq(struct spu_context *ctx)
+{
+       spin_lock(&spu_prio->runq_lock);
+       __spu_add_to_rq(ctx);
+       spin_unlock(&spu_prio->runq_lock);
+}
+
 static void __spu_del_from_rq(struct spu_context *ctx)
 {
        int prio = ctx->prio;
@@ -468,10 +489,24 @@ static void __spu_del_from_rq(struct spu_context *ctx)
        }
 }
 
+void spu_del_from_rq(struct spu_context *ctx)
+{
+       spin_lock(&spu_prio->runq_lock);
+       __spu_del_from_rq(ctx);
+       spin_unlock(&spu_prio->runq_lock);
+}
+
 static void spu_prio_wait(struct spu_context *ctx)
 {
        DEFINE_WAIT(wait);
 
+       /*
+        * The caller must explicitly wait for a context to be loaded
+        * if the nosched flag is set.  If NOSCHED is not set, the caller
+        * queues the context and waits for an spu event or error.
+        */
+       BUG_ON(!(ctx->flags & SPU_CREATE_NOSCHED));
+
        spin_lock(&spu_prio->runq_lock);
        prepare_to_wait_exclusive(&ctx->stop_wq, &wait, TASK_INTERRUPTIBLE);
        if (!signal_pending(current)) {
@@ -555,7 +590,7 @@ static struct spu *find_victim(struct spu_context *ctx)
        /*
         * Look for a possible preemption candidate on the local node first.
         * If there is no candidate look at the other nodes.  This isn't
-        * exactly fair, but so far the whole spu schedule tries to keep
+        * exactly fair, but so far the whole spu scheduler tries to keep
         * a strong node affinity.  We might want to fine-tune this in
         * the future.
         */
@@ -571,6 +606,7 @@ static struct spu *find_victim(struct spu_context *ctx)
                        struct spu_context *tmp = spu->ctx;
 
                        if (tmp && tmp->prio > ctx->prio &&
+                           !(tmp->flags & SPU_CREATE_NOSCHED) &&
                            (!victim || tmp->prio > victim->prio))
                                victim = spu->ctx;
                }
@@ -582,6 +618,10 @@ static struct spu *find_victim(struct spu_context *ctx)
                         * higher priority contexts before lower priority
                         * ones, so this is safe until we introduce
                         * priority inheritance schemes.
+                        *
+                        * XXX if the highest priority context is locked,
+                        * this can loop a long time.  Might be better to
+                        * look at another context or give up after X retries.
                         */
                        if (!mutex_trylock(&victim->state_mutex)) {
                                victim = NULL;
@@ -589,10 +629,10 @@ static struct spu *find_victim(struct spu_context *ctx)
                        }
 
                        spu = victim->spu;
-                       if (!spu) {
+                       if (!spu || victim->prio <= ctx->prio) {
                                /*
                                 * This race can happen because we've dropped
-                                * the active list mutex.  No a problem, just
+                                * the active list mutex.  Not a problem, just
                                 * restart the search.
                                 */
                                mutex_unlock(&victim->state_mutex);
@@ -607,13 +647,10 @@ static struct spu *find_victim(struct spu_context *ctx)
 
                        victim->stats.invol_ctx_switch++;
                        spu->stats.invol_ctx_switch++;
+                       spu_add_to_rq(victim);
+
                        mutex_unlock(&victim->state_mutex);
-                       /*
-                        * We need to break out of the wait loop in spu_run
-                        * manually to ensure this context gets put on the
-                        * runqueue again ASAP.
-                        */
-                       wake_up(&victim->stop_wq);
+
                        return spu;
                }
        }
@@ -621,6 +658,50 @@ static struct spu *find_victim(struct spu_context *ctx)
        return NULL;
 }
 
+static void __spu_schedule(struct spu *spu, struct spu_context *ctx)
+{
+       int node = spu->node;
+       int success = 0;
+
+       spu_set_timeslice(ctx);
+
+       mutex_lock(&cbe_spu_info[node].list_mutex);
+       if (spu->ctx == NULL) {
+               spu_bind_context(spu, ctx);
+               cbe_spu_info[node].nr_active++;
+               spu->alloc_state = SPU_USED;
+               success = 1;
+       }
+       mutex_unlock(&cbe_spu_info[node].list_mutex);
+
+       if (success)
+               wake_up_all(&ctx->run_wq);
+       else
+               spu_add_to_rq(ctx);
+}
+
+static void spu_schedule(struct spu *spu, struct spu_context *ctx)
+{
+       /* not a candidate for interruptible because it's called either
+          from the scheduler thread or from spu_deactivate */
+       mutex_lock(&ctx->state_mutex);
+       __spu_schedule(spu, ctx);
+       spu_release(ctx);
+}
+
+static void spu_unschedule(struct spu *spu, struct spu_context *ctx)
+{
+       int node = spu->node;
+
+       mutex_lock(&cbe_spu_info[node].list_mutex);
+       cbe_spu_info[node].nr_active--;
+       spu->alloc_state = SPU_FREE;
+       spu_unbind_context(spu, ctx);
+       ctx->stats.invol_ctx_switch++;
+       spu->stats.invol_ctx_switch++;
+       mutex_unlock(&cbe_spu_info[node].list_mutex);
+}
+
 /**
  * spu_activate - find a free spu for a context and execute it
  * @ctx:       spu context to schedule
@@ -632,39 +713,47 @@ static struct spu *find_victim(struct spu_context *ctx)
  */
 int spu_activate(struct spu_context *ctx, unsigned long flags)
 {
-       do {
-               struct spu *spu;
+       struct spu *spu;
 
-               /*
-                * If there are multiple threads waiting for a single context
-                * only one actually binds the context while the others will
-                * only be able to acquire the state_mutex once the context
-                * already is in runnable state.
-                */
-               if (ctx->spu)
-                       return 0;
+       /*
+        * If there are multiple threads waiting for a single context
+        * only one actually binds the context while the others will
+        * only be able to acquire the state_mutex once the context
+        * already is in runnable state.
+        */
+       if (ctx->spu)
+               return 0;
 
-               spu = spu_get_idle(ctx);
-               /*
-                * If this is a realtime thread we try to get it running by
-                * preempting a lower priority thread.
-                */
-               if (!spu && rt_prio(ctx->prio))
-                       spu = find_victim(ctx);
-               if (spu) {
-                       int node = spu->node;
+spu_activate_top:
+       if (signal_pending(current))
+               return -ERESTARTSYS;
 
-                       mutex_lock(&cbe_spu_info[node].list_mutex);
-                       spu_bind_context(spu, ctx);
-                       cbe_spu_info[node].nr_active++;
-                       mutex_unlock(&cbe_spu_info[node].list_mutex);
-                       return 0;
-               }
+       spu = spu_get_idle(ctx);
+       /*
+        * If this is a realtime thread we try to get it running by
+        * preempting a lower priority thread.
+        */
+       if (!spu && rt_prio(ctx->prio))
+               spu = find_victim(ctx);
+       if (spu) {
+               unsigned long runcntl;
+
+               runcntl = ctx->ops->runcntl_read(ctx);
+               __spu_schedule(spu, ctx);
+               if (runcntl & SPU_RUNCNTL_RUNNABLE)
+                       spuctx_switch_state(ctx, SPU_UTIL_USER);
 
+               return 0;
+       }
+
+       if (ctx->flags & SPU_CREATE_NOSCHED) {
                spu_prio_wait(ctx);
-       } while (!signal_pending(current));
+               goto spu_activate_top;
+       }
 
-       return -ERESTARTSYS;
+       spu_add_to_rq(ctx);
+
+       return 0;
 }
 
 /**
@@ -706,21 +795,19 @@ static int __spu_deactivate(struct spu_context *ctx, int force, int max_prio)
        if (spu) {
                new = grab_runnable_context(max_prio, spu->node);
                if (new || force) {
-                       int node = spu->node;
-
-                       mutex_lock(&cbe_spu_info[node].list_mutex);
-                       spu_unbind_context(spu, ctx);
-                       spu->alloc_state = SPU_FREE;
-                       cbe_spu_info[node].nr_active--;
-                       mutex_unlock(&cbe_spu_info[node].list_mutex);
-
-                       ctx->stats.vol_ctx_switch++;
-                       spu->stats.vol_ctx_switch++;
-
-                       if (new)
-                               wake_up(&new->stop_wq);
+                       spu_unschedule(spu, ctx);
+                       if (new) {
+                               if (new->flags & SPU_CREATE_NOSCHED)
+                                       wake_up(&new->stop_wq);
+                               else {
+                                       spu_release(ctx);
+                                       spu_schedule(spu, new);
+                                       /* this one can't easily be made
+                                          interruptible */
+                                       mutex_lock(&ctx->state_mutex);
+                               }
+                       }
                }
-
        }
 
        return new != NULL;
@@ -757,43 +844,38 @@ void spu_yield(struct spu_context *ctx)
 
 static noinline void spusched_tick(struct spu_context *ctx)
 {
+       struct spu_context *new = NULL;
+       struct spu *spu = NULL;
+       u32 status;
+
+       if (spu_acquire(ctx))
+               BUG();  /* a kernel thread never has signals pending */
+
+       if (ctx->state != SPU_STATE_RUNNABLE)
+               goto out;
+       if (spu_stopped(ctx, &status))
+               goto out;
        if (ctx->flags & SPU_CREATE_NOSCHED)
-               return;
+               goto out;
        if (ctx->policy == SCHED_FIFO)
-               return;
+               goto out;
 
        if (--ctx->time_slice)
-               return;
+               goto out;
 
-       /*
-        * Unfortunately list_mutex ranks outside of state_mutex, so
-        * we have to trylock here.  If we fail give the context another
-        * tick and try again.
-        */
-       if (mutex_trylock(&ctx->state_mutex)) {
-               struct spu *spu = ctx->spu;
-               struct spu_context *new;
-
-               new = grab_runnable_context(ctx->prio + 1, spu->node);
-               if (new) {
-                       spu_unbind_context(spu, ctx);
-                       ctx->stats.invol_ctx_switch++;
-                       spu->stats.invol_ctx_switch++;
-                       spu->alloc_state = SPU_FREE;
-                       cbe_spu_info[spu->node].nr_active--;
-                       wake_up(&new->stop_wq);
-                       /*
-                        * We need to break out of the wait loop in
-                        * spu_run manually to ensure this context
-                        * gets put on the runqueue again ASAP.
-                        */
-                       wake_up(&ctx->stop_wq);
-               }
-               spu_set_timeslice(ctx);
-               mutex_unlock(&ctx->state_mutex);
+       spu = ctx->spu;
+       new = grab_runnable_context(ctx->prio + 1, spu->node);
+       if (new) {
+               spu_unschedule(spu, ctx);
+               spu_add_to_rq(ctx);
        } else {
                ctx->time_slice++;
        }
+out:
+       spu_release(ctx);
+
+       if (new)
+               spu_schedule(spu, new);
 }
 
 /**
@@ -817,35 +899,31 @@ static unsigned long count_active_contexts(void)
 }
 
 /**
- * spu_calc_load - given tick count, update the avenrun load estimates.
- * @tick:      tick count
+ * spu_calc_load - update the avenrun load estimates.
  *
  * No locking against reading these values from userspace, as for
  * the CPU loadavg code.
  */
-static void spu_calc_load(unsigned long ticks)
+static void spu_calc_load(void)
 {
        unsigned long active_tasks; /* fixed-point */
-       static int count = LOAD_FREQ;
-
-       count -= ticks;
-
-       if (unlikely(count < 0)) {
-               active_tasks = count_active_contexts() * FIXED_1;
-               do {
-                       CALC_LOAD(spu_avenrun[0], EXP_1, active_tasks);
-                       CALC_LOAD(spu_avenrun[1], EXP_5, active_tasks);
-                       CALC_LOAD(spu_avenrun[2], EXP_15, active_tasks);
-                       count += LOAD_FREQ;
-               } while (count < 0);
-       }
+
+       active_tasks = count_active_contexts() * FIXED_1;
+       CALC_LOAD(spu_avenrun[0], EXP_1, active_tasks);
+       CALC_LOAD(spu_avenrun[1], EXP_5, active_tasks);
+       CALC_LOAD(spu_avenrun[2], EXP_15, active_tasks);
 }
 
 static void spusched_wake(unsigned long data)
 {
        mod_timer(&spusched_timer, jiffies + SPUSCHED_TICK);
        wake_up_process(spusched_task);
-       spu_calc_load(SPUSCHED_TICK);
+}
+
+static void spuloadavg_wake(unsigned long data)
+{
+       mod_timer(&spuloadavg_timer, jiffies + LOAD_FREQ);
+       spu_calc_load();
 }
 
 static int spusched_thread(void *unused)
@@ -857,17 +935,58 @@ static int spusched_thread(void *unused)
                set_current_state(TASK_INTERRUPTIBLE);
                schedule();
                for (node = 0; node < MAX_NUMNODES; node++) {
-                       mutex_lock(&cbe_spu_info[node].list_mutex);
-                       list_for_each_entry(spu, &cbe_spu_info[node].spus, cbe_list)
-                               if (spu->ctx)
-                                       spusched_tick(spu->ctx);
-                       mutex_unlock(&cbe_spu_info[node].list_mutex);
+                       struct mutex *mtx = &cbe_spu_info[node].list_mutex;
+
+                       mutex_lock(mtx);
+                       list_for_each_entry(spu, &cbe_spu_info[node].spus,
+                                       cbe_list) {
+                               struct spu_context *ctx = spu->ctx;
+
+                               if (ctx) {
+                                       mutex_unlock(mtx);
+                                       spusched_tick(ctx);
+                                       mutex_lock(mtx);
+                               }
+                       }
+                       mutex_unlock(mtx);
                }
        }
 
        return 0;
 }
 
+void spuctx_switch_state(struct spu_context *ctx,
+               enum spu_utilization_state new_state)
+{
+       unsigned long long curtime;
+       signed long long delta;
+       struct timespec ts;
+       struct spu *spu;
+       enum spu_utilization_state old_state;
+
+       ktime_get_ts(&ts);
+       curtime = timespec_to_ns(&ts);
+       delta = curtime - ctx->stats.tstamp;
+
+       WARN_ON(!mutex_is_locked(&ctx->state_mutex));
+       WARN_ON(delta < 0);
+
+       spu = ctx->spu;
+       old_state = ctx->stats.util_state;
+       ctx->stats.util_state = new_state;
+       ctx->stats.tstamp = curtime;
+
+       /*
+        * Update the physical SPU utilization statistics.
+        */
+       if (spu) {
+               ctx->stats.times[old_state] += delta;
+               spu->stats.times[old_state] += delta;
+               spu->stats.util_state = new_state;
+               spu->stats.tstamp = curtime;
+       }
+}
+
 #define LOAD_INT(x) ((x) >> FSHIFT)
 #define LOAD_FRAC(x) LOAD_INT(((x) & (FIXED_1-1)) * 100)
 
@@ -881,7 +1000,7 @@ static int show_spu_loadavg(struct seq_file *s, void *private)
 
        /*
         * Note that last_pid doesn't really make much sense for the
-        * SPU loadavg (it even seems very odd on the CPU side..),
+        * SPU loadavg (it even seems very odd on the CPU side...),
         * but we include it here to have a 100% compatible interface.
         */
        seq_printf(s, "%d.%02d %d.%02d %d.%02d %ld/%d %d\n",
@@ -922,6 +1041,7 @@ int __init spu_sched_init(void)
        spin_lock_init(&spu_prio->runq_lock);
 
        setup_timer(&spusched_timer, spusched_wake, 0);
+       setup_timer(&spuloadavg_timer, spuloadavg_wake, 0);
 
        spusched_task = kthread_run(spusched_thread, NULL, "spusched");
        if (IS_ERR(spusched_task)) {
@@ -929,6 +1049,8 @@ int __init spu_sched_init(void)
                goto out_free_spu_prio;
        }
 
+       mod_timer(&spuloadavg_timer, 0);
+
        entry = create_proc_entry("spu_loadavg", 0, NULL);
        if (!entry)
                goto out_stop_kthread;
@@ -954,6 +1076,7 @@ void spu_sched_exit(void)
        remove_proc_entry("spu_loadavg", NULL);
 
        del_timer_sync(&spusched_timer);
+       del_timer_sync(&spuloadavg_timer);
        kthread_stop(spusched_task);
 
        for (node = 0; node < MAX_NUMNODES; node++) {