[CELL] spufs: add spu stats in sysfs and ctx stat file in spufs

This patch exports per-context statistics in spufs as long as spu
statistics in sysfs.

It was formed by merging:
"spufs: add spu stats in sysfs"   From: Christoph Hellwig
"spufs: add stat file to spufs"   From: Christoph Hellwig
"spufs: fix libassist accounting" From: Jeremy Kerr
"spusched: fix spu utilization statistics" From: Luke Browning
And some adjustments by myself, after suggestions on cbe-oss-dev.

Having separate patches was making the review process harder
than it should, as we end up integrating spus and ctx statistics
accounting much more than it was on the first implementation.

Signed-off-by: Andre Detsch <adetsch@br.ibm.com>
Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
Signed-off-by: Arnd Bergmann <arnd.bergmann@de.ibm.com>
diff --git a/arch/powerpc/platforms/cell/spu_base.c b/arch/powerpc/platforms/cell/spu_base.c
index c563066..caaf2bf 100644
--- a/arch/powerpc/platforms/cell/spu_base.c
+++ b/arch/powerpc/platforms/cell/spu_base.c
@@ -553,6 +553,7 @@
 	int ret;
 	static int number;
 	unsigned long flags;
+	struct timespec ts;
 
 	ret = -ENOMEM;
 	spu = kzalloc(sizeof (*spu), GFP_KERNEL);
@@ -586,8 +587,9 @@
 	spin_unlock_irqrestore(&spu_list_lock, flags);
 	mutex_unlock(&spu_mutex);
 
-	spu->stats.utilization_state = SPU_UTIL_IDLE;
-	spu->stats.tstamp = jiffies;
+	spu->stats.util_state = SPU_UTIL_IDLE_LOADED;
+	ktime_get_ts(&ts);
+	spu->stats.tstamp = timespec_to_ns(&ts);
 
 	goto out;
 
@@ -608,12 +610,20 @@
 static unsigned long long spu_acct_time(struct spu *spu,
 		enum spu_utilization_state state)
 {
+	struct timespec ts;
 	unsigned long long time = spu->stats.times[state];
 
-	if (spu->stats.utilization_state == state)
-		time += jiffies - spu->stats.tstamp;
+	/*
+	 * If the spu is idle or the context is stopped, utilization
+	 * statistics are not updated.  Apply the time delta from the
+	 * last recorded state of the spu.
+	 */
+	if (spu->stats.util_state == state) {
+		ktime_get_ts(&ts);
+		time += timespec_to_ns(&ts) - spu->stats.tstamp;
+	}
 
-	return jiffies_to_msecs(time);
+	return time / NSEC_PER_MSEC;
 }
 
 
@@ -623,11 +633,11 @@
 
 	return sprintf(buf, "%s %llu %llu %llu %llu "
 		      "%llu %llu %llu %llu %llu %llu %llu %llu\n",
-		spu_state_names[spu->stats.utilization_state],
+		spu_state_names[spu->stats.util_state],
 		spu_acct_time(spu, SPU_UTIL_USER),
 		spu_acct_time(spu, SPU_UTIL_SYSTEM),
 		spu_acct_time(spu, SPU_UTIL_IOWAIT),
-		spu_acct_time(spu, SPU_UTIL_IDLE),
+		spu_acct_time(spu, SPU_UTIL_IDLE_LOADED),
 		spu->stats.vol_ctx_switch,
 		spu->stats.invol_ctx_switch,
 		spu->stats.slb_flt,
diff --git a/arch/powerpc/platforms/cell/spufs/context.c b/arch/powerpc/platforms/cell/spufs/context.c
index 6d7bd60..0e5e55f 100644
--- a/arch/powerpc/platforms/cell/spufs/context.c
+++ b/arch/powerpc/platforms/cell/spufs/context.c
@@ -59,8 +59,7 @@
 		spu_gang_add_ctx(gang, ctx);
 	ctx->cpus_allowed = current->cpus_allowed;
 	spu_set_timeslice(ctx);
-	ctx->stats.execution_state = SPUCTX_UTIL_USER;
-	ctx->stats.tstamp = jiffies;
+	ctx->stats.util_state = SPU_UTIL_IDLE_LOADED;
 
 	atomic_inc(&nr_spu_contexts);
 	goto out;
diff --git a/arch/powerpc/platforms/cell/spufs/fault.c b/arch/powerpc/platforms/cell/spufs/fault.c
index f53a074..917eab4 100644
--- a/arch/powerpc/platforms/cell/spufs/fault.c
+++ b/arch/powerpc/platforms/cell/spufs/fault.c
@@ -179,16 +179,14 @@
 	if (!(dsisr & (MFC_DSISR_PTE_NOT_FOUND | MFC_DSISR_ACCESS_DENIED)))
 		return 0;
 
-	spuctx_switch_state(ctx, SPUCTX_UTIL_IOWAIT);
+	spuctx_switch_state(ctx, SPU_UTIL_IOWAIT);
 
 	pr_debug("ctx %p: ea %016lx, dsisr %016lx state %d\n", ctx, ea,
 		dsisr, ctx->state);
 
 	ctx->stats.hash_flt++;
-	if (ctx->state == SPU_STATE_RUNNABLE) {
+	if (ctx->state == SPU_STATE_RUNNABLE)
 		ctx->spu->stats.hash_flt++;
-		spu_switch_state(ctx->spu, SPU_UTIL_IOWAIT);
-	}
 
 	/* we must not hold the lock when entering spu_handle_mm_fault */
 	spu_release(ctx);
@@ -226,7 +224,7 @@
 	} else
 		spufs_handle_dma_error(ctx, ea, SPE_EVENT_SPE_DATA_STORAGE);
 
-	spuctx_switch_state(ctx, SPUCTX_UTIL_SYSTEM);
+	spuctx_switch_state(ctx, SPU_UTIL_SYSTEM);
 	return ret;
 }
 EXPORT_SYMBOL_GPL(spufs_handle_class1);
diff --git a/arch/powerpc/platforms/cell/spufs/file.c b/arch/powerpc/platforms/cell/spufs/file.c
index fe16411..9351db9 100644
--- a/arch/powerpc/platforms/cell/spufs/file.c
+++ b/arch/powerpc/platforms/cell/spufs/file.c
@@ -2079,14 +2079,26 @@
 };
 
 static unsigned long long spufs_acct_time(struct spu_context *ctx,
-		enum spuctx_execution_state state)
+		enum spu_utilization_state state)
 {
-	unsigned long time = ctx->stats.times[state];
+	struct timespec ts;
+	unsigned long long time = ctx->stats.times[state];
 
-	if (ctx->stats.execution_state == state)
-		time += jiffies - ctx->stats.tstamp;
+	/*
+	 * In general, utilization statistics are updated by the controlling
+	 * thread as the spu context moves through various well defined
+	 * state transitions, but if the context is lazily loaded its
+	 * utilization statistics are not updated as the controlling thread
+	 * is not tightly coupled with the execution of the spu context.  We
+	 * calculate and apply the time delta from the last recorded state
+	 * of the spu context.
+	 */
+	if (ctx->spu && ctx->stats.util_state == state) {
+		ktime_get_ts(&ts);
+		time += timespec_to_ns(&ts) - ctx->stats.tstamp;
+	}
 
-	return jiffies_to_msecs(time);
+	return time / NSEC_PER_MSEC;
 }
 
 static unsigned long long spufs_slb_flts(struct spu_context *ctx)
@@ -2121,11 +2133,11 @@
 	spu_acquire(ctx);
 	seq_printf(s, "%s %llu %llu %llu %llu "
 		      "%llu %llu %llu %llu %llu %llu %llu %llu\n",
-		ctx_state_names[ctx->stats.execution_state],
-		spufs_acct_time(ctx, SPUCTX_UTIL_USER),
-		spufs_acct_time(ctx, SPUCTX_UTIL_SYSTEM),
-		spufs_acct_time(ctx, SPUCTX_UTIL_IOWAIT),
-		spufs_acct_time(ctx, SPUCTX_UTIL_LOADED),
+		ctx_state_names[ctx->stats.util_state],
+		spufs_acct_time(ctx, SPU_UTIL_USER),
+		spufs_acct_time(ctx, SPU_UTIL_SYSTEM),
+		spufs_acct_time(ctx, SPU_UTIL_IOWAIT),
+		spufs_acct_time(ctx, SPU_UTIL_IDLE_LOADED),
 		ctx->stats.vol_ctx_switch,
 		ctx->stats.invol_ctx_switch,
 		spufs_slb_flts(ctx),
diff --git a/arch/powerpc/platforms/cell/spufs/run.c b/arch/powerpc/platforms/cell/spufs/run.c
index 58ae13b..8c91b3f 100644
--- a/arch/powerpc/platforms/cell/spufs/run.c
+++ b/arch/powerpc/platforms/cell/spufs/run.c
@@ -126,6 +126,8 @@
 
 static int spu_run_init(struct spu_context *ctx, u32 * npc)
 {
+	spuctx_switch_state(ctx, SPU_UTIL_SYSTEM);
+
 	if (ctx->flags & SPU_CREATE_ISOLATE) {
 		unsigned long runcntl;
 
@@ -151,6 +153,8 @@
 		ctx->ops->runcntl_write(ctx, SPU_RUNCNTL_RUNNABLE);
 	}
 
+	spuctx_switch_state(ctx, SPU_UTIL_USER);
+
 	return 0;
 }
 
@@ -161,6 +165,8 @@
 
 	*status = ctx->ops->status_read(ctx);
 	*npc = ctx->ops->npc_read(ctx);
+
+	spuctx_switch_state(ctx, SPU_UTIL_IDLE_LOADED);
 	spu_release(ctx);
 
 	if (signal_pending(current))
@@ -328,6 +334,9 @@
 		ret = spufs_wait(ctx->stop_wq, spu_stopped(ctx, &status));
 		if (unlikely(ret))
 			break;
+
+		spuctx_switch_state(ctx, SPU_UTIL_SYSTEM);
+
 		if ((status & SPU_STATUS_STOPPED_BY_STOP) &&
 		    (status >> SPU_STOP_STATUS_SHIFT == 0x2104)) {
 			ret = spu_process_callback(ctx);
@@ -356,6 +365,7 @@
 	    (ctx->state == SPU_STATE_RUNNABLE))
 		ctx->stats.libassist++;
 
+
 	ctx->ops->master_stop(ctx);
 	ret = spu_run_fini(ctx, npc, &status);
 	spu_yield(ctx);
diff --git a/arch/powerpc/platforms/cell/spufs/sched.c b/arch/powerpc/platforms/cell/spufs/sched.c
index fe78930..ecd9e95 100644
--- a/arch/powerpc/platforms/cell/spufs/sched.c
+++ b/arch/powerpc/platforms/cell/spufs/sched.c
@@ -229,6 +229,7 @@
 {
 	pr_debug("%s: pid=%d SPU=%d NODE=%d\n", __FUNCTION__, current->pid,
 		 spu->number, spu->node);
+	spuctx_switch_state(ctx, SPU_UTIL_SYSTEM);
 
 	ctx->stats.slb_flt_base = spu->stats.slb_flt;
 	ctx->stats.class2_intr_base = spu->stats.class2_intr;
@@ -251,7 +252,8 @@
 	spu_cpu_affinity_set(spu, raw_smp_processor_id());
 	spu_switch_notify(spu, ctx);
 	ctx->state = SPU_STATE_RUNNABLE;
-	spu_switch_state(spu, SPU_UTIL_SYSTEM);
+
+	spuctx_switch_state(ctx, SPU_UTIL_IDLE_LOADED);
 }
 
 /**
@@ -263,8 +265,7 @@
 {
 	pr_debug("%s: unbind pid=%d SPU=%d NODE=%d\n", __FUNCTION__,
 		 spu->pid, spu->number, spu->node);
-
-	spu_switch_state(spu, SPU_UTIL_IDLE);
+	spuctx_switch_state(ctx, SPU_UTIL_SYSTEM);
 
 	spu_switch_notify(spu, NULL);
 	spu_unmap_mappings(ctx);
@@ -279,7 +280,6 @@
 	spu_associate_mm(spu, NULL);
 	spu->pid = 0;
 	ctx->ops = &spu_backing_ops;
-	ctx->spu = NULL;
 	spu->flags = 0;
 	spu->ctx = NULL;
 
@@ -287,6 +287,10 @@
 		(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;
 }
 
 /**
@@ -455,8 +459,6 @@
  */
 int spu_activate(struct spu_context *ctx, unsigned long flags)
 {
-	spuctx_switch_state(ctx, SPUCTX_UTIL_SYSTEM);
-
 	do {
 		struct spu *spu;
 
@@ -551,7 +553,6 @@
 void spu_deactivate(struct spu_context *ctx)
 {
 	__spu_deactivate(ctx, 1, MAX_PRIO);
-	spuctx_switch_state(ctx, SPUCTX_UTIL_USER);
 }
 
 /**
@@ -566,12 +567,7 @@
 {
 	if (!(ctx->flags & SPU_CREATE_NOSCHED)) {
 		mutex_lock(&ctx->state_mutex);
-		if (__spu_deactivate(ctx, 0, MAX_PRIO))
-			spuctx_switch_state(ctx, SPUCTX_UTIL_USER);
-		else {
-			spuctx_switch_state(ctx, SPUCTX_UTIL_LOADED);
-			spu_switch_state(ctx->spu, SPU_UTIL_USER);
-		}
+		__spu_deactivate(ctx, 0, MAX_PRIO);
 		mutex_unlock(&ctx->state_mutex);
 	}
 }
diff --git a/arch/powerpc/platforms/cell/spufs/spufs.h b/arch/powerpc/platforms/cell/spufs/spufs.h
index 34d5f9f..fdace92 100644
--- a/arch/powerpc/platforms/cell/spufs/spufs.h
+++ b/arch/powerpc/platforms/cell/spufs/spufs.h
@@ -40,19 +40,6 @@
 struct spu_context_ops;
 struct spu_gang;
 
-/*
- * This is the state for spu utilization reporting to userspace.
- * Because this state is visible to userspace it must never change and needs
- * to be kept strictly separate from any internal state kept by the kernel.
- */
-enum spuctx_execution_state {
-	SPUCTX_UTIL_USER = 0,
-	SPUCTX_UTIL_SYSTEM,
-	SPUCTX_UTIL_IOWAIT,
-	SPUCTX_UTIL_LOADED,
-	SPUCTX_UTIL_MAX
-};
-
 struct spu_context {
 	struct spu *spu;		  /* pointer to a physical SPU */
 	struct spu_state csa;		  /* SPU context save area. */
@@ -104,9 +91,9 @@
 	/* statistics */
 	struct {
 		/* updates protected by ctx->state_mutex */
-		enum spuctx_execution_state execution_state;
-		unsigned long tstamp;		/* time of last ctx switch */
-		unsigned long times[SPUCTX_UTIL_MAX];
+		enum spu_utilization_state util_state;
+		unsigned long long tstamp;	/* time of last state switch */
+		unsigned long long times[SPU_UTIL_MAX];
 		unsigned long long vol_ctx_switch;
 		unsigned long long invol_ctx_switch;
 		unsigned long long min_flt;
@@ -293,30 +280,34 @@
  * line.
  */
 static inline void spuctx_switch_state(struct spu_context *ctx,
-		enum spuctx_execution_state new_state)
+		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);
 
-	if (ctx->stats.execution_state != new_state) {
-		unsigned long curtime = jiffies;
+	spu = ctx->spu;
+	old_state = ctx->stats.util_state;
+	ctx->stats.util_state = new_state;
+	ctx->stats.tstamp = curtime;
 
-		ctx->stats.times[ctx->stats.execution_state] +=
-				 curtime - ctx->stats.tstamp;
-		ctx->stats.tstamp = curtime;
-		ctx->stats.execution_state = new_state;
-	}
-}
-
-static inline void spu_switch_state(struct spu *spu,
-		enum spuctx_execution_state new_state)
-{
-	if (spu->stats.utilization_state != new_state) {
-		unsigned long curtime = jiffies;
-
-		spu->stats.times[spu->stats.utilization_state] +=
-				 curtime - spu->stats.tstamp;
+	/*
+	 * 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;
-		spu->stats.utilization_state = new_state;
 	}
 }