bcache: Better alloc tracepoints

Change the invalidate tracepoint to indicate how much data we're invalidating,
and change the alloc tracepoints to indicate what offset they're for.
Signed-off-by: Kent Overstreet <kmo@daterainc.com>

drivers/md/bcache/alloc.c

@@ -162,10 +162,15 @@ static bool can_invalidate_bucket(struct cache *ca, struct bucket *b)
 
 static void invalidate_one_bucket(struct cache *ca, struct bucket *b)
 {
+	size_t bucket = b - ca->buckets;
+
+	if (GC_SECTORS_USED(b))
+		trace_bcache_invalidate(ca, bucket);
+
 	bch_inc_gen(ca, b);
 	b->prio = INITIAL_PRIO;
 	atomic_inc(&b->pin);
-	fifo_push(&ca->free_inc, b - ca->buckets);
+	fifo_push(&ca->free_inc, bucket);
 }
 
 /*
@@ -301,8 +306,6 @@ static void invalidate_buckets(struct cache *ca)
 		invalidate_buckets_random(ca);
 		break;
 	}
-
-	trace_bcache_alloc_invalidate(ca);
 }
 
 #define allocator_wait(ca, cond)					\
@@ -408,8 +411,10 @@ long bch_bucket_alloc(struct cache *ca, unsigned reserve, bool wait)
 	    fifo_pop(&ca->free[reserve], r))
 		goto out;
 
-	if (!wait)
+	if (!wait) {
+		trace_bcache_alloc_fail(ca, reserve);
 		return -1;
+	}
 
 	do {
 		prepare_to_wait(&ca->set->bucket_wait, &w,
@@ -425,6 +430,8 @@ long bch_bucket_alloc(struct cache *ca, unsigned reserve, bool wait)
 out:
 	wake_up_process(ca->alloc_thread);
 
+	trace_bcache_alloc(ca, reserve);
+
 	if (expensive_debug_checks(ca->set)) {
 		size_t iter;
 		long i;

drivers/md/bcache/trace.c

@@ -45,7 +45,7 @@ EXPORT_TRACEPOINT_SYMBOL_GPL(bcache_btree_node_split);
 EXPORT_TRACEPOINT_SYMBOL_GPL(bcache_btree_node_compact);
 EXPORT_TRACEPOINT_SYMBOL_GPL(bcache_btree_set_root);
 
-EXPORT_TRACEPOINT_SYMBOL_GPL(bcache_alloc_invalidate);
+EXPORT_TRACEPOINT_SYMBOL_GPL(bcache_invalidate);
 EXPORT_TRACEPOINT_SYMBOL_GPL(bcache_alloc_fail);
 
 EXPORT_TRACEPOINT_SYMBOL_GPL(bcache_writeback);

include/trace/events/bcache.h

@@ -399,26 +399,43 @@ TRACE_EVENT(bcache_keyscan,
 
 /* Allocator */
 
-TRACE_EVENT(bcache_alloc_invalidate,
-	TP_PROTO(struct cache *ca),
-	TP_ARGS(ca),
+TRACE_EVENT(bcache_invalidate,
+	TP_PROTO(struct cache *ca, size_t bucket),
+	TP_ARGS(ca, bucket),
 
 	TP_STRUCT__entry(
-		__field(unsigned,	free			)
-		__field(unsigned,	free_inc		)
-		__field(unsigned,	free_inc_size		)
-		__field(unsigned,	unused			)
+		__field(unsigned,	sectors			)
+		__field(dev_t,		dev			)
+		__field(__u64,		offset			)
 	),
 
 	TP_fast_assign(
-		__entry->free		= fifo_used(&ca->free[RESERVE_NONE]);
-		__entry->free_inc	= fifo_used(&ca->free_inc);
-		__entry->free_inc_size	= ca->free_inc.size;
-		__entry->unused		= fifo_used(&ca->unused);
+		__entry->dev		= ca->bdev->bd_dev;
+		__entry->offset		= bucket << ca->set->bucket_bits;
+		__entry->sectors	= GC_SECTORS_USED(&ca->buckets[bucket]);
 	),
 
-	TP_printk("free %u free_inc %u/%u unused %u", __entry->free,
-		  __entry->free_inc, __entry->free_inc_size, __entry->unused)
+	TP_printk("invalidated %u sectors at %d,%d sector=%llu",
+		  __entry->sectors, MAJOR(__entry->dev),
+		  MINOR(__entry->dev), __entry->offset)
+);
+
+TRACE_EVENT(bcache_alloc,
+	TP_PROTO(struct cache *ca, size_t bucket),
+	TP_ARGS(ca, bucket),
+
+	TP_STRUCT__entry(
+		__field(dev_t,		dev			)
+		__field(__u64,		offset			)
+	),
+
+	TP_fast_assign(
+		__entry->dev		= ca->bdev->bd_dev;
+		__entry->offset		= bucket << ca->set->bucket_bits;
+	),
+
+	TP_printk("allocated %d,%d sector=%llu", MAJOR(__entry->dev),
+		  MINOR(__entry->dev), __entry->offset)
 );
 
 TRACE_EVENT(bcache_alloc_fail,
@@ -426,6 +443,7 @@ TRACE_EVENT(bcache_alloc_fail,
 	TP_ARGS(ca, reserve),
 
 	TP_STRUCT__entry(
+		__field(dev_t,		dev			)
 		__field(unsigned,	free			)
 		__field(unsigned,	free_inc		)
 		__field(unsigned,	unused			)
@@ -433,13 +451,15 @@ TRACE_EVENT(bcache_alloc_fail,
 	),
 
 	TP_fast_assign(
+		__entry->dev		= ca->bdev->bd_dev;
 		__entry->free		= fifo_used(&ca->free[reserve]);
 		__entry->free_inc	= fifo_used(&ca->free_inc);
 		__entry->unused		= fifo_used(&ca->unused);
 		__entry->blocked	= atomic_read(&ca->set->prio_blocked);
 	),
 
-	TP_printk("free %u free_inc %u unused %u blocked %u", __entry->free,
+	TP_printk("alloc fail %d,%d free %u free_inc %u unused %u blocked %u",
+		  MAJOR(__entry->dev), MINOR(__entry->dev), __entry->free,
 		  __entry->free_inc, __entry->unused, __entry->blocked)
 );