bcachefs: Better bucket alloc tracepoints

Tracepoints are garbage, and perf trace even cuts off some of our
fields.

Much nicer to just trace a string, and then we can build nicely
formatted output with printbufs.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

fs/bcachefs/alloc_foreground.c

@@ -511,6 +511,44 @@ static struct open_bucket *bch2_bucket_alloc_freelist(struct btree_trans *trans,
 	return ob;
 }
 
+static noinline void trace_bucket_alloc2(struct bch_fs *c, struct bch_dev *ca,
+					 enum bch_watermark watermark,
+					 enum bch_data_type data_type,
+					 struct closure *cl,
+					 struct bch_dev_usage *usage,
+					 struct bucket_alloc_state *s,
+					 struct open_bucket *ob)
+{
+	struct printbuf buf = PRINTBUF;
+
+	printbuf_tabstop_push(&buf, 24);
+
+	prt_printf(&buf, "dev\t%s (%u)\n",	ca->name, ca->dev_idx);
+	prt_printf(&buf, "watermark\t%s\n",	bch2_watermarks[watermark]);
+	prt_printf(&buf, "data type\t%s\n",	__bch2_data_types[data_type]);
+	prt_printf(&buf, "blocking\t%u\n",	cl != NULL);
+	prt_printf(&buf, "free\t%llu\n",	usage->d[BCH_DATA_free].buckets);
+	prt_printf(&buf, "avail\t%llu\n",	dev_buckets_free(ca, *usage, watermark));
+	prt_printf(&buf, "copygc_wait\t%lu/%lli\n",
+		   bch2_copygc_wait_amount(c),
+		   c->copygc_wait - atomic64_read(&c->io_clock[WRITE].now));
+	prt_printf(&buf, "seen\t%llu\n",	s->buckets_seen);
+	prt_printf(&buf, "open\t%llu\n",	s->skipped_open);
+	prt_printf(&buf, "need journal commit\t%llu\n", s->skipped_need_journal_commit);
+	prt_printf(&buf, "nocow\t%llu\n",	s->skipped_nocow);
+	prt_printf(&buf, "nouse\t%llu\n",	s->skipped_nouse);
+
+	if (!IS_ERR(ob)) {
+		prt_printf(&buf, "allocated\t%llu\n", ob->bucket);
+		trace_bucket_alloc(c, buf.buf);
+	} else {
+		prt_printf(&buf, "err\t%s\n", bch2_err_str(PTR_ERR(ob)));
+		trace_bucket_alloc_fail(c, buf.buf);
+	}
+
+	printbuf_exit(&buf);
+}
+
 /**
  * bch2_bucket_alloc_trans - allocate a single bucket from a specific device
  * @trans:	transaction object
@@ -583,27 +621,14 @@ static struct open_bucket *bch2_bucket_alloc_trans(struct btree_trans *trans,
 		ob->data_type = data_type;
 
 	if (!IS_ERR(ob))
-		trace_and_count(c, bucket_alloc, ca,
-				bch2_watermarks[watermark],
-				ob->bucket,
-				usage->d[BCH_DATA_free].buckets,
-				avail,
-				bch2_copygc_wait_amount(c),
-				c->copygc_wait - atomic64_read(&c->io_clock[WRITE].now),
-				&s,
-				cl == NULL,
-				"");
+		count_event(c, bucket_alloc);
 	else if (!bch2_err_matches(PTR_ERR(ob), BCH_ERR_transaction_restart))
-		trace_and_count(c, bucket_alloc_fail, ca,
-				bch2_watermarks[watermark],
-				0,
-				usage->d[BCH_DATA_free].buckets,
-				avail,
-				bch2_copygc_wait_amount(c),
-				c->copygc_wait - atomic64_read(&c->io_clock[WRITE].now),
-				&s,
-				cl == NULL,
-				bch2_err_str(PTR_ERR(ob)));
+		count_event(c, bucket_alloc_fail);
+
+	if (!IS_ERR(ob)
+	    ? trace_bucket_alloc_enabled()
+	    : trace_bucket_alloc_fail_enabled())
+		trace_bucket_alloc2(c, ca, watermark, data_type, cl, usage, &s, ob);
 
 	return ob;
 }

fs/bcachefs/trace.h

@@ -638,99 +638,14 @@ DEFINE_EVENT(bch_fs, gc_gens_end,
 
 /* Allocator */
 
-DECLARE_EVENT_CLASS(bucket_alloc,
-	TP_PROTO(struct bch_dev *ca, const char *alloc_reserve,
-		 u64 bucket,
-		 u64 free,
-		 u64 avail,
-		 u64 copygc_wait_amount,
-		 s64 copygc_waiting_for,
-		 struct bucket_alloc_state *s,
-		 bool nonblocking,
-		 const char *err),
-	TP_ARGS(ca, alloc_reserve, bucket, free, avail,
-		copygc_wait_amount, copygc_waiting_for,
-		s, nonblocking, err),
-
-	TP_STRUCT__entry(
-		__field(u8,			dev			)
-		__array(char,	reserve,	16			)
-		__field(u64,			bucket	)
-		__field(u64,			free			)
-		__field(u64,			avail			)
-		__field(u64,			copygc_wait_amount	)
-		__field(s64,			copygc_waiting_for	)
-		__field(u64,			seen			)
-		__field(u64,			open			)
-		__field(u64,			need_journal_commit	)
-		__field(u64,			nouse			)
-		__field(bool,			nonblocking		)
-		__field(u64,			nocow			)
-		__array(char,			err,	32		)
-	),
-
-	TP_fast_assign(
-		__entry->dev		= ca->dev_idx;
-		strscpy(__entry->reserve, alloc_reserve, sizeof(__entry->reserve));
-		__entry->bucket		= bucket;
-		__entry->free		= free;
-		__entry->avail		= avail;
-		__entry->copygc_wait_amount	= copygc_wait_amount;
-		__entry->copygc_waiting_for	= copygc_waiting_for;
-		__entry->seen		= s->buckets_seen;
-		__entry->open		= s->skipped_open;
-		__entry->need_journal_commit = s->skipped_need_journal_commit;
-		__entry->nouse		= s->skipped_nouse;
-		__entry->nonblocking	= nonblocking;
-		__entry->nocow		= s->skipped_nocow;
-		strscpy(__entry->err, err, sizeof(__entry->err));
-	),
-
-	TP_printk("reserve %s bucket %u:%llu free %llu avail %llu copygc_wait %llu/%lli seen %llu open %llu need_journal_commit %llu nouse %llu nocow %llu nonblocking %u err %s",
-		  __entry->reserve,
-		  __entry->dev,
-		  __entry->bucket,
-		  __entry->free,
-		  __entry->avail,
-		  __entry->copygc_wait_amount,
-		  __entry->copygc_waiting_for,
-		  __entry->seen,
-		  __entry->open,
-		  __entry->need_journal_commit,
-		  __entry->nouse,
-		  __entry->nocow,
-		  __entry->nonblocking,
-		  __entry->err)
+DEFINE_EVENT(fs_str, bucket_alloc,
+	TP_PROTO(struct bch_fs *c, const char *str),
+	TP_ARGS(c, str)
 );
 
-DEFINE_EVENT(bucket_alloc, bucket_alloc,
-	TP_PROTO(struct bch_dev *ca, const char *alloc_reserve,
-		 u64 bucket,
-		 u64 free,
-		 u64 avail,
-		 u64 copygc_wait_amount,
-		 s64 copygc_waiting_for,
-		 struct bucket_alloc_state *s,
-		 bool nonblocking,
-		 const char *err),
-	TP_ARGS(ca, alloc_reserve, bucket, free, avail,
-		copygc_wait_amount, copygc_waiting_for,
-		s, nonblocking, err)
-);
-
-DEFINE_EVENT(bucket_alloc, bucket_alloc_fail,
-	TP_PROTO(struct bch_dev *ca, const char *alloc_reserve,
-		 u64 bucket,
-		 u64 free,
-		 u64 avail,
-		 u64 copygc_wait_amount,
-		 s64 copygc_waiting_for,
-		 struct bucket_alloc_state *s,
-		 bool nonblocking,
-		 const char *err),
-	TP_ARGS(ca, alloc_reserve, bucket, free, avail,
-		copygc_wait_amount, copygc_waiting_for,
-		s, nonblocking, err)
+DEFINE_EVENT(fs_str, bucket_alloc_fail,
+	TP_PROTO(struct bch_fs *c, const char *str),
+	TP_ARGS(c, str)
 );
 
 TRACE_EVENT(discard_buckets,