Adding upstream version 6.1.76.upstream/6.1.76

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1141 insertions, 0 deletions

diff --git a/arch/powerpc/platforms/cell/spufs/sched.c b/arch/powerpc/platforms/cell/spufs/sched.c
new file mode 100644
index 000000000..99bd027a7
--- /dev/null
+++ b/arch/powerpc/platforms/cell/spufs/sched.c
@@ -0,0 +1,1141 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/* sched.c - SPU scheduler.
+ *
+ * Copyright (C) IBM 2005
+ * Author: Mark Nutter <mnutter@us.ibm.com>
+ *
+ * 2006-03-31	NUMA domains added.
+ */
+
+#undef DEBUG
+
+#include <linux/errno.h>
+#include <linux/sched/signal.h>
+#include <linux/sched/loadavg.h>
+#include <linux/sched/rt.h>
+#include <linux/kernel.h>
+#include <linux/mm.h>
+#include <linux/slab.h>
+#include <linux/completion.h>
+#include <linux/vmalloc.h>
+#include <linux/smp.h>
+#include <linux/stddef.h>
+#include <linux/unistd.h>
+#include <linux/numa.h>
+#include <linux/mutex.h>
+#include <linux/notifier.h>
+#include <linux/kthread.h>
+#include <linux/pid_namespace.h>
+#include <linux/proc_fs.h>
+#include <linux/seq_file.h>
+
+#include <asm/io.h>
+#include <asm/mmu_context.h>
+#include <asm/spu.h>
+#include <asm/spu_csa.h>
+#include <asm/spu_priv1.h>
+#include "spufs.h"
+#define CREATE_TRACE_POINTS
+#include "sputrace.h"
+
+struct spu_prio_array {
+	DECLARE_BITMAP(bitmap, MAX_PRIO);
+	struct list_head runq[MAX_PRIO];
+	spinlock_t runq_lock;
+	int nr_waiting;
+};
+
+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).
+ */
+#define NORMAL_PRIO		120
+
+/*
+ * Frequency of the spu scheduler tick.  By default we do one SPU scheduler
+ * tick for every 10 CPU scheduler ticks.
+ */
+#define SPUSCHED_TICK		(10)
+
+/*
+ * These are the 'tuning knobs' of the scheduler:
+ *
+ * Minimum timeslice is 5 msecs (or 1 spu scheduler tick, whichever is
+ * larger), default timeslice is 100 msecs, maximum timeslice is 800 msecs.
+ */
+#define MIN_SPU_TIMESLICE	max(5 * HZ / (1000 * SPUSCHED_TICK), 1)
+#define DEF_SPU_TIMESLICE	(100 * HZ / (1000 * SPUSCHED_TICK))
+
+#define SCALE_PRIO(x, prio) \
+	max(x * (MAX_PRIO - prio) / (NICE_WIDTH / 2), MIN_SPU_TIMESLICE)
+
+/*
+ * scale user-nice values [ -20 ... 0 ... 19 ] to time slice values:
+ * [800ms ... 100ms ... 5ms]
+ *
+ * The higher a thread's priority, the bigger timeslices
+ * it gets during one round of execution. But even the lowest
+ * priority thread gets MIN_TIMESLICE worth of execution time.
+ */
+void spu_set_timeslice(struct spu_context *ctx)
+{
+	if (ctx->prio < NORMAL_PRIO)
+		ctx->time_slice = SCALE_PRIO(DEF_SPU_TIMESLICE * 4, ctx->prio);
+	else
+		ctx->time_slice = SCALE_PRIO(DEF_SPU_TIMESLICE, ctx->prio);
+}
+
+/*
+ * Update scheduling information from the owning thread.
+ */
+void __spu_update_sched_info(struct spu_context *ctx)
+{
+	/*
+	 * 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 this field
+	 * contains junk for threads with a realtime scheduling
+	 * policy so we have to look at ->prio in this case.
+	 */
+	if (rt_prio(current->prio))
+		ctx->prio = current->prio;
+	else
+		ctx->prio = current->static_prio;
+	ctx->policy = current->policy;
+
+	/*
+	 * 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.
+	 */
+	cpumask_copy(&ctx->cpus_allowed, current->cpus_ptr);
+
+	/* Save the current cpu id for spu interrupt routing. */
+	ctx->last_ran = raw_smp_processor_id();
+}
+
+void spu_update_sched_info(struct spu_context *ctx)
+{
+	int node;
+
+	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)
+{
+	if (nr_cpus_node(node)) {
+		const struct cpumask *mask = cpumask_of_node(node);
+
+		if (cpumask_intersects(mask, &ctx->cpus_allowed))
+			return 1;
+	}
+
+	return 0;
+}
+
+static int node_allowed(struct spu_context *ctx, int node)
+{
+	int rval;
+
+	spin_lock(&spu_prio->runq_lock);
+	rval = __node_allowed(ctx, node);
+	spin_unlock(&spu_prio->runq_lock);
+
+	return rval;
+}
+
+void do_notify_spus_active(void)
+{
+	int node;
+
+	/*
+	 * Wake up the active spu_contexts.
+	 */
+	for_each_online_node(node) {
+		struct spu *spu;
+
+		mutex_lock(&cbe_spu_info[node].list_mutex);
+		list_for_each_entry(spu, &cbe_spu_info[node].spus, cbe_list) {
+			if (spu->alloc_state != SPU_FREE) {
+				struct spu_context *ctx = spu->ctx;
+				set_bit(SPU_SCHED_NOTIFY_ACTIVE,
+					&ctx->sched_flags);
+				mb();
+				wake_up_all(&ctx->stop_wq);
+			}
+		}
+		mutex_unlock(&cbe_spu_info[node].list_mutex);
+	}
+}
+
+/**
+ * spu_bind_context - bind spu context to physical spu
+ * @spu:	physical spu to bind to
+ * @ctx:	context to bind
+ */
+static void spu_bind_context(struct spu *spu, struct spu_context *ctx)
+{
+	spu_context_trace(spu_bind_context__enter, ctx, spu);
+
+	spuctx_switch_state(ctx, SPU_UTIL_SYSTEM);
+
+	if (ctx->flags & SPU_CREATE_NOSCHED)
+		atomic_inc(&cbe_spu_info[spu->node].reserved_spus);
+
+	ctx->stats.slb_flt_base = spu->stats.slb_flt;
+	ctx->stats.class2_intr_base = spu->stats.class2_intr;
+
+	spu_associate_mm(spu, ctx->owner);
+
+	spin_lock_irq(&spu->register_lock);
+	spu->ctx = ctx;
+	spu->flags = 0;
+	ctx->spu = spu;
+	ctx->ops = &spu_hw_ops;
+	spu->pid = current->pid;
+	spu->tgid = current->tgid;
+	spu->ibox_callback = spufs_ibox_callback;
+	spu->wbox_callback = spufs_wbox_callback;
+	spu->stop_callback = spufs_stop_callback;
+	spu->mfc_callback = spufs_mfc_callback;
+	spin_unlock_irq(&spu->register_lock);
+
+	spu_unmap_mappings(ctx);
+
+	spu_switch_log_notify(spu, ctx, SWITCH_LOG_START, 0);
+	spu_restore(&ctx->csa, spu);
+	spu->timestamp = jiffies;
+	ctx->state = SPU_STATE_RUNNABLE;
+
+	spuctx_switch_state(ctx, SPU_UTIL_USER);
+}
+
+/*
+ * Must be used with the list_mutex held.
+ */
+static inline int sched_spu(struct spu *spu)
+{
+	BUG_ON(!mutex_is_locked(&cbe_spu_info[spu->node].list_mutex));
+
+	return (!spu->ctx || !(spu->ctx->flags & SPU_CREATE_NOSCHED));
+}
+
+static void aff_merge_remaining_ctxs(struct spu_gang *gang)
+{
+	struct spu_context *ctx;
+
+	list_for_each_entry(ctx, &gang->aff_list_head, aff_list) {
+		if (list_empty(&ctx->aff_list))
+			list_add(&ctx->aff_list, &gang->aff_list_head);
+	}
+	gang->aff_flags |= AFF_MERGED;
+}
+
+static void aff_set_offsets(struct spu_gang *gang)
+{
+	struct spu_context *ctx;
+	int offset;
+
+	offset = -1;
+	list_for_each_entry_reverse(ctx, &gang->aff_ref_ctx->aff_list,
+								aff_list) {
+		if (&ctx->aff_list == &gang->aff_list_head)
+			break;
+		ctx->aff_offset = offset--;
+	}
+
+	offset = 0;
+	list_for_each_entry(ctx, gang->aff_ref_ctx->aff_list.prev, aff_list) {
+		if (&ctx->aff_list == &gang->aff_list_head)
+			break;
+		ctx->aff_offset = offset++;
+	}
+
+	gang->aff_flags |= AFF_OFFSETS_SET;
+}
+
+static struct spu *aff_ref_location(struct spu_context *ctx, int mem_aff,
+		 int group_size, int lowest_offset)
+{
+	struct spu *spu;
+	int node, n;
+
+	/*
+	 * TODO: A better algorithm could be used to find a good spu to be
+	 *       used as reference location for the ctxs chain.
+	 */
+	node = cpu_to_node(raw_smp_processor_id());
+	for (n = 0; n < MAX_NUMNODES; n++, node++) {
+		/*
+		 * "available_spus" counts how many spus are not potentially
+		 * going to be used by other affinity gangs whose reference
+		 * context is already in place. Although this code seeks to
+		 * avoid having affinity gangs with a summed amount of
+		 * contexts bigger than the amount of spus in the node,
+		 * this may happen sporadically. In this case, available_spus
+		 * becomes negative, which is harmless.
+		 */
+		int available_spus;
+
+		node = (node < MAX_NUMNODES) ? node : 0;
+		if (!node_allowed(ctx, node))
+			continue;
+
+		available_spus = 0;
+		mutex_lock(&cbe_spu_info[node].list_mutex);
+		list_for_each_entry(spu, &cbe_spu_info[node].spus, cbe_list) {
+			if (spu->ctx && spu->ctx->gang && !spu->ctx->aff_offset
+					&& spu->ctx->gang->aff_ref_spu)
+				available_spus -= spu->ctx->gang->contexts;
+			available_spus++;
+		}
+		if (available_spus < ctx->gang->contexts) {
+			mutex_unlock(&cbe_spu_info[node].list_mutex);
+			continue;
+		}
+
+		list_for_each_entry(spu, &cbe_spu_info[node].spus, cbe_list) {
+			if ((!mem_aff || spu->has_mem_affinity) &&
+							sched_spu(spu)) {
+				mutex_unlock(&cbe_spu_info[node].list_mutex);
+				return spu;
+			}
+		}
+		mutex_unlock(&cbe_spu_info[node].list_mutex);
+	}
+	return NULL;
+}
+
+static void aff_set_ref_point_location(struct spu_gang *gang)
+{
+	int mem_aff, gs, lowest_offset;
+	struct spu_context *tmp, *ctx;
+
+	mem_aff = gang->aff_ref_ctx->flags & SPU_CREATE_AFFINITY_MEM;
+	lowest_offset = 0;
+	gs = 0;
+
+	list_for_each_entry(tmp, &gang->aff_list_head, aff_list)
+		gs++;
+
+	list_for_each_entry_reverse(ctx, &gang->aff_ref_ctx->aff_list,
+								aff_list) {
+		if (&ctx->aff_list == &gang->aff_list_head)
+			break;
+		lowest_offset = ctx->aff_offset;
+	}
+
+	gang->aff_ref_spu = aff_ref_location(gang->aff_ref_ctx, mem_aff, gs,
+							lowest_offset);
+}
+
+static struct spu *ctx_location(struct spu *ref, int offset, int node)
+{
+	struct spu *spu;
+
+	spu = NULL;
+	if (offset >= 0) {
+		list_for_each_entry(spu, ref->aff_list.prev, aff_list) {
+			BUG_ON(spu->node != node);
+			if (offset == 0)
+				break;
+			if (sched_spu(spu))
+				offset--;
+		}
+	} else {
+		list_for_each_entry_reverse(spu, ref->aff_list.next, aff_list) {
+			BUG_ON(spu->node != node);
+			if (offset == 0)
+				break;
+			if (sched_spu(spu))
+				offset++;
+		}
+	}
+
+	return spu;
+}
+
+/*
+ * affinity_check is called each time a context is going to be scheduled.
+ * It returns the spu ptr on which the context must run.
+ */
+static int has_affinity(struct spu_context *ctx)
+{
+	struct spu_gang *gang = ctx->gang;
+
+	if (list_empty(&ctx->aff_list))
+		return 0;
+
+	if (atomic_read(&ctx->gang->aff_sched_count) == 0)
+		ctx->gang->aff_ref_spu = NULL;
+
+	if (!gang->aff_ref_spu) {
+		if (!(gang->aff_flags & AFF_MERGED))
+			aff_merge_remaining_ctxs(gang);
+		if (!(gang->aff_flags & AFF_OFFSETS_SET))
+			aff_set_offsets(gang);
+		aff_set_ref_point_location(gang);
+	}
+
+	return gang->aff_ref_spu != NULL;
+}
+
+/**
+ * spu_unbind_context - unbind spu context from physical spu
+ * @spu:	physical spu to unbind from
+ * @ctx:	context to unbind
+ */
+static void spu_unbind_context(struct spu *spu, struct spu_context *ctx)
+{
+	u32 status;
+
+	spu_context_trace(spu_unbind_context__enter, ctx, spu);
+
+	spuctx_switch_state(ctx, SPU_UTIL_SYSTEM);
+
+ 	if (spu->ctx->flags & SPU_CREATE_NOSCHED)
+		atomic_dec(&cbe_spu_info[spu->node].reserved_spus);
+
+	if (ctx->gang)
+		/*
+		 * If ctx->gang->aff_sched_count is positive, SPU affinity is
+		 * being considered in this gang. Using atomic_dec_if_positive
+		 * allow us to skip an explicit check for affinity in this gang
+		 */
+		atomic_dec_if_positive(&ctx->gang->aff_sched_count);
+
+	spu_unmap_mappings(ctx);
+	spu_save(&ctx->csa, spu);
+	spu_switch_log_notify(spu, ctx, SWITCH_LOG_STOP, 0);
+
+	spin_lock_irq(&spu->register_lock);
+	spu->timestamp = jiffies;
+	ctx->state = SPU_STATE_SAVED;
+	spu->ibox_callback = NULL;
+	spu->wbox_callback = NULL;
+	spu->stop_callback = NULL;
+	spu->mfc_callback = NULL;
+	spu->pid = 0;
+	spu->tgid = 0;
+	ctx->ops = &spu_backing_ops;
+	spu->flags = 0;
+	spu->ctx = NULL;
+	spin_unlock_irq(&spu->register_lock);
+
+	spu_associate_mm(spu, NULL);
+
+	ctx->stats.slb_flt +=
+		(spu->stats.slb_flt - ctx->stats.slb_flt_base);
+	ctx->stats.class2_intr +=
+		(spu->stats.class2_intr - ctx->stats.class2_intr_base);
+
+	/* This maps the underlying spu state to idle */
+	spuctx_switch_state(ctx, SPU_UTIL_IDLE_LOADED);
+	ctx->spu = NULL;
+
+	if (spu_stopped(ctx, &status))
+		wake_up_all(&ctx->stop_wq);
+}
+
+/**
+ * spu_add_to_rq - add a context to the runqueue
+ * @ctx:       context to add
+ */
+static void __spu_add_to_rq(struct spu_context *ctx)
+{
+	/*
+	 * Unfortunately this code path can be called from multiple threads
+	 * on behalf of a single context due to the way the problem state
+	 * mmap support works.
+	 *
+	 * Fortunately we need to wake up all these threads at the same time
+	 * and can simply skip the runqueue addition for every but the first
+	 * thread getting into this codepath.
+	 *
+	 * It's still quite hacky, and long-term we should proxy all other
+	 * threads through the owner thread so that spu_run is in control
+	 * of all the scheduling activity for a given context.
+	 */
+	if (list_empty(&ctx->rq)) {
+		list_add_tail(&ctx->rq, &spu_prio->runq[ctx->prio]);
+		set_bit(ctx->prio, spu_prio->bitmap);
+		if (!spu_prio->nr_waiting++)
+			mod_timer(&spusched_timer, jiffies + SPUSCHED_TICK);
+	}
+}
+
+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;
+
+	if (!list_empty(&ctx->rq)) {
+		if (!--spu_prio->nr_waiting)
+			del_timer(&spusched_timer);
+		list_del_init(&ctx->rq);
+
+		if (list_empty(&spu_prio->runq[prio]))
+			clear_bit(prio, spu_prio->bitmap);
+	}
+}
+
+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)) {
+		__spu_add_to_rq(ctx);
+		spin_unlock(&spu_prio->runq_lock);
+		mutex_unlock(&ctx->state_mutex);
+		schedule();
+		mutex_lock(&ctx->state_mutex);
+		spin_lock(&spu_prio->runq_lock);
+		__spu_del_from_rq(ctx);
+	}
+	spin_unlock(&spu_prio->runq_lock);
+	__set_current_state(TASK_RUNNING);
+	remove_wait_queue(&ctx->stop_wq, &wait);
+}
+
+static struct spu *spu_get_idle(struct spu_context *ctx)
+{
+	struct spu *spu, *aff_ref_spu;
+	int node, n;
+
+	spu_context_nospu_trace(spu_get_idle__enter, ctx);
+
+	if (ctx->gang) {
+		mutex_lock(&ctx->gang->aff_mutex);
+		if (has_affinity(ctx)) {
+			aff_ref_spu = ctx->gang->aff_ref_spu;
+			atomic_inc(&ctx->gang->aff_sched_count);
+			mutex_unlock(&ctx->gang->aff_mutex);
+			node = aff_ref_spu->node;
+
+			mutex_lock(&cbe_spu_info[node].list_mutex);
+			spu = ctx_location(aff_ref_spu, ctx->aff_offset, node);
+			if (spu && spu->alloc_state == SPU_FREE)
+				goto found;
+			mutex_unlock(&cbe_spu_info[node].list_mutex);
+
+			atomic_dec(&ctx->gang->aff_sched_count);
+			goto not_found;
+		}
+		mutex_unlock(&ctx->gang->aff_mutex);
+	}
+	node = cpu_to_node(raw_smp_processor_id());
+	for (n = 0; n < MAX_NUMNODES; n++, node++) {
+		node = (node < MAX_NUMNODES) ? node : 0;
+		if (!node_allowed(ctx, node))
+			continue;
+
+		mutex_lock(&cbe_spu_info[node].list_mutex);
+		list_for_each_entry(spu, &cbe_spu_info[node].spus, cbe_list) {
+			if (spu->alloc_state == SPU_FREE)
+				goto found;
+		}
+		mutex_unlock(&cbe_spu_info[node].list_mutex);
+	}
+
+ not_found:
+	spu_context_nospu_trace(spu_get_idle__not_found, ctx);
+	return NULL;
+
+ found:
+	spu->alloc_state = SPU_USED;
+	mutex_unlock(&cbe_spu_info[node].list_mutex);
+	spu_context_trace(spu_get_idle__found, ctx, spu);
+	spu_init_channels(spu);
+	return spu;
+}
+
+/**
+ * find_victim - find a lower priority context to preempt
+ * @ctx:	candidate context for running
+ *
+ * Returns the freed physical spu to run the new context on.
+ */
+static struct spu *find_victim(struct spu_context *ctx)
+{
+	struct spu_context *victim = NULL;
+	struct spu *spu;
+	int node, n;
+
+	spu_context_nospu_trace(spu_find_victim__enter, 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 scheduler tries to keep
+	 * a strong node affinity.  We might want to fine-tune this in
+	 * the future.
+	 */
+ restart:
+	node = cpu_to_node(raw_smp_processor_id());
+	for (n = 0; n < MAX_NUMNODES; n++, node++) {
+		node = (node < MAX_NUMNODES) ? node : 0;
+		if (!node_allowed(ctx, node))
+			continue;
+
+		mutex_lock(&cbe_spu_info[node].list_mutex);
+		list_for_each_entry(spu, &cbe_spu_info[node].spus, cbe_list) {
+			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;
+			}
+		}
+		if (victim)
+			get_spu_context(victim);
+		mutex_unlock(&cbe_spu_info[node].list_mutex);
+
+		if (victim) {
+			/*
+			 * This nests ctx->state_mutex, but we always lock
+			 * 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)) {
+				put_spu_context(victim);
+				victim = NULL;
+				goto restart;
+			}
+
+			spu = victim->spu;
+			if (!spu || victim->prio <= ctx->prio) {
+				/*
+				 * This race can happen because we've dropped
+				 * the active list mutex.  Not a problem, just
+				 * restart the search.
+				 */
+				mutex_unlock(&victim->state_mutex);
+				put_spu_context(victim);
+				victim = NULL;
+				goto restart;
+			}
+
+			spu_context_trace(__spu_deactivate__unload, ctx, spu);
+
+			mutex_lock(&cbe_spu_info[node].list_mutex);
+			cbe_spu_info[node].nr_active--;
+			spu_unbind_context(spu, victim);
+			mutex_unlock(&cbe_spu_info[node].list_mutex);
+
+			victim->stats.invol_ctx_switch++;
+			spu->stats.invol_ctx_switch++;
+			if (test_bit(SPU_SCHED_SPU_RUN, &victim->sched_flags))
+				spu_add_to_rq(victim);
+
+			mutex_unlock(&victim->state_mutex);
+			put_spu_context(victim);
+
+			return spu;
+		}
+	}
+
+	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);
+	if (ctx->state == SPU_STATE_SAVED)
+		__spu_schedule(spu, ctx);
+	spu_release(ctx);
+}
+
+/**
+ * spu_unschedule - remove a context from a spu, and possibly release it.
+ * @spu:	The SPU to unschedule from
+ * @ctx:	The context currently scheduled on the SPU
+ * @free_spu	Whether to free the SPU for other contexts
+ *
+ * Unbinds the context @ctx from the SPU @spu. If @free_spu is non-zero, the
+ * SPU is made available for other contexts (ie, may be returned by
+ * spu_get_idle). If this is zero, the caller is expected to schedule another
+ * context to this spu.
+ *
+ * Should be called with ctx->state_mutex held.
+ */
+static void spu_unschedule(struct spu *spu, struct spu_context *ctx,
+		int free_spu)
+{
+	int node = spu->node;
+
+	mutex_lock(&cbe_spu_info[node].list_mutex);
+	cbe_spu_info[node].nr_active--;
+	if (free_spu)
+		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
+ * @flags:	flags (currently ignored)
+ *
+ * Tries to find a free spu to run @ctx.  If no free spu is available
+ * add the context to the runqueue so it gets woken up once an spu
+ * is available.
+ */
+int spu_activate(struct spu_context *ctx, unsigned long flags)
+{
+	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;
+
+spu_activate_top:
+	if (signal_pending(current))
+		return -ERESTARTSYS;
+
+	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);
+		goto spu_activate_top;
+	}
+
+	spu_add_to_rq(ctx);
+
+	return 0;
+}
+
+/**
+ * grab_runnable_context - try to find a runnable context
+ *
+ * Remove the highest priority context on the runqueue and return it
+ * to the caller.  Returns %NULL if no runnable context was found.
+ */
+static struct spu_context *grab_runnable_context(int prio, int node)
+{
+	struct spu_context *ctx;
+	int best;
+
+	spin_lock(&spu_prio->runq_lock);
+	best = find_first_bit(spu_prio->bitmap, prio);
+	while (best < prio) {
+		struct list_head *rq = &spu_prio->runq[best];
+
+		list_for_each_entry(ctx, rq, rq) {
+			/* XXX(hch): check for affinity here as well */
+			if (__node_allowed(ctx, node)) {
+				__spu_del_from_rq(ctx);
+				goto found;
+			}
+		}
+		best++;
+	}
+	ctx = NULL;
+ found:
+	spin_unlock(&spu_prio->runq_lock);
+	return ctx;
+}
+
+static int __spu_deactivate(struct spu_context *ctx, int force, int max_prio)
+{
+	struct spu *spu = ctx->spu;
+	struct spu_context *new = NULL;
+
+	if (spu) {
+		new = grab_runnable_context(max_prio, spu->node);
+		if (new || force) {
+			spu_unschedule(spu, ctx, new == NULL);
+			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;
+}
+
+/**
+ * spu_deactivate - unbind a context from it's physical spu
+ * @ctx:	spu context to unbind
+ *
+ * Unbind @ctx from the physical spu it is running on and schedule
+ * the highest priority context to run on the freed physical spu.
+ */
+void spu_deactivate(struct spu_context *ctx)
+{
+	spu_context_nospu_trace(spu_deactivate__enter, ctx);
+	__spu_deactivate(ctx, 1, MAX_PRIO);
+}
+
+/**
+ * spu_yield -	yield a physical spu if others are waiting
+ * @ctx:	spu context to yield
+ *
+ * Check if there is a higher priority context waiting and if yes
+ * unbind @ctx from the physical spu and schedule the highest
+ * priority context to run on the freed physical spu instead.
+ */
+void spu_yield(struct spu_context *ctx)
+{
+	spu_context_nospu_trace(spu_yield__enter, ctx);
+	if (!(ctx->flags & SPU_CREATE_NOSCHED)) {
+		mutex_lock(&ctx->state_mutex);
+		__spu_deactivate(ctx, 0, MAX_PRIO);
+		mutex_unlock(&ctx->state_mutex);
+	}
+}
+
+static noinline void spusched_tick(struct spu_context *ctx)
+{
+	struct spu_context *new = NULL;
+	struct spu *spu = NULL;
+
+	if (spu_acquire(ctx))
+		BUG();	/* a kernel thread never has signals pending */
+
+	if (ctx->state != SPU_STATE_RUNNABLE)
+		goto out;
+	if (ctx->flags & SPU_CREATE_NOSCHED)
+		goto out;
+	if (ctx->policy == SCHED_FIFO)
+		goto out;
+
+	if (--ctx->time_slice && test_bit(SPU_SCHED_SPU_RUN, &ctx->sched_flags))
+		goto out;
+
+	spu = ctx->spu;
+
+	spu_context_trace(spusched_tick__preempt, ctx, spu);
+
+	new = grab_runnable_context(ctx->prio + 1, spu->node);
+	if (new) {
+		spu_unschedule(spu, ctx, 0);
+		if (test_bit(SPU_SCHED_SPU_RUN, &ctx->sched_flags))
+			spu_add_to_rq(ctx);
+	} else {
+		spu_context_nospu_trace(spusched_tick__newslice, ctx);
+		if (!ctx->time_slice)
+			ctx->time_slice++;
+	}
+out:
+	spu_release(ctx);
+
+	if (new)
+		spu_schedule(spu, new);
+}
+
+/**
+ * count_active_contexts - count nr of active tasks
+ *
+ * Return the number of tasks currently running or waiting to run.
+ *
+ * Note that we don't take runq_lock / list_mutex here.  Reading
+ * a single 32bit value is atomic on powerpc, and we don't care
+ * about memory ordering issues here.
+ */
+static unsigned long count_active_contexts(void)
+{
+	int nr_active = 0, node;
+
+	for (node = 0; node < MAX_NUMNODES; node++)
+		nr_active += cbe_spu_info[node].nr_active;
+	nr_active += spu_prio->nr_waiting;
+
+	return nr_active;
+}
+
+/**
+ * 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(void)
+{
+	unsigned long active_tasks; /* fixed-point */
+
+	active_tasks = count_active_contexts() * FIXED_1;
+	spu_avenrun[0] = calc_load(spu_avenrun[0], EXP_1, active_tasks);
+	spu_avenrun[1] = calc_load(spu_avenrun[1], EXP_5, active_tasks);
+	spu_avenrun[2] = calc_load(spu_avenrun[2], EXP_15, active_tasks);
+}
+
+static void spusched_wake(struct timer_list *unused)
+{
+	mod_timer(&spusched_timer, jiffies + SPUSCHED_TICK);
+	wake_up_process(spusched_task);
+}
+
+static void spuloadavg_wake(struct timer_list *unused)
+{
+	mod_timer(&spuloadavg_timer, jiffies + LOAD_FREQ);
+	spu_calc_load();
+}
+
+static int spusched_thread(void *unused)
+{
+	struct spu *spu;
+	int node;
+
+	while (!kthread_should_stop()) {
+		set_current_state(TASK_INTERRUPTIBLE);
+		schedule();
+		for (node = 0; node < MAX_NUMNODES; node++) {
+			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) {
+					get_spu_context(ctx);
+					mutex_unlock(mtx);
+					spusched_tick(ctx);
+					mutex_lock(mtx);
+					put_spu_context(ctx);
+				}
+			}
+			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 spu *spu;
+	enum spu_utilization_state old_state;
+	int node;
+
+	curtime = ktime_get_ns();
+	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;
+		node = spu->node;
+		if (old_state == SPU_UTIL_USER)
+			atomic_dec(&cbe_spu_info[node].busy_spus);
+		if (new_state == SPU_UTIL_USER)
+			atomic_inc(&cbe_spu_info[node].busy_spus);
+	}
+}
+
+#ifdef CONFIG_PROC_FS
+static int show_spu_loadavg(struct seq_file *s, void *private)
+{
+	int a, b, c;
+
+	a = spu_avenrun[0] + (FIXED_1/200);
+	b = spu_avenrun[1] + (FIXED_1/200);
+	c = spu_avenrun[2] + (FIXED_1/200);
+
+	/*
+	 * Note that last_pid doesn't really make much sense for the
+	 * 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",
+		LOAD_INT(a), LOAD_FRAC(a),
+		LOAD_INT(b), LOAD_FRAC(b),
+		LOAD_INT(c), LOAD_FRAC(c),
+		count_active_contexts(),
+		atomic_read(&nr_spu_contexts),
+		idr_get_cursor(&task_active_pid_ns(current)->idr) - 1);
+	return 0;
+}
+#endif
+
+int __init spu_sched_init(void)
+{
+	struct proc_dir_entry *entry;
+	int err = -ENOMEM, i;
+
+	spu_prio = kzalloc(sizeof(struct spu_prio_array), GFP_KERNEL);
+	if (!spu_prio)
+		goto out;
+
+	for (i = 0; i < MAX_PRIO; i++) {
+		INIT_LIST_HEAD(&spu_prio->runq[i]);
+		__clear_bit(i, spu_prio->bitmap);
+	}
+	spin_lock_init(&spu_prio->runq_lock);
+
+	timer_setup(&spusched_timer, spusched_wake, 0);
+	timer_setup(&spuloadavg_timer, spuloadavg_wake, 0);
+
+	spusched_task = kthread_run(spusched_thread, NULL, "spusched");
+	if (IS_ERR(spusched_task)) {
+		err = PTR_ERR(spusched_task);
+		goto out_free_spu_prio;
+	}
+
+	mod_timer(&spuloadavg_timer, 0);
+
+	entry = proc_create_single("spu_loadavg", 0, NULL, show_spu_loadavg);
+	if (!entry)
+		goto out_stop_kthread;
+
+	pr_debug("spusched: tick: %d, min ticks: %d, default ticks: %d\n",
+			SPUSCHED_TICK, MIN_SPU_TIMESLICE, DEF_SPU_TIMESLICE);
+	return 0;
+
+ out_stop_kthread:
+	kthread_stop(spusched_task);
+ out_free_spu_prio:
+	kfree(spu_prio);
+ out:
+	return err;
+}
+
+void spu_sched_exit(void)
+{
+	struct spu *spu;
+	int node;
+
+	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++) {
+		mutex_lock(&cbe_spu_info[node].list_mutex);
+		list_for_each_entry(spu, &cbe_spu_info[node].spus, cbe_list)
+			if (spu->alloc_state != SPU_FREE)
+				spu->alloc_state = SPU_FREE;
+		mutex_unlock(&cbe_spu_info[node].list_mutex);
+	}
+	kfree(spu_prio);
+}