writeback: trace event bdi_dirty_ratelimit

It helps understand how various throttle bandwidths are updated. Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>

writeback: trace event bdi_dirty_ratelimit
It helps understand how various throttle bandwidths are updated. Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
Wu Fengguang
1 parent 50657fc4df
Showing 2 changed files with 47 additions and 0 deletions Side-by-side Diff
include/trace/events/writeback.h
mm/page-writeback.c
@@ -226,6 +226,51 @@
 	)
 );
  
+#define KBps(x)			((x) << (PAGE_SHIFT - 10))
+
+TRACE_EVENT(bdi_dirty_ratelimit,
+
+	TP_PROTO(struct backing_dev_info *bdi,
+		 unsigned long dirty_rate,
+		 unsigned long task_ratelimit),
+
+	TP_ARGS(bdi, dirty_rate, task_ratelimit),
+
+	TP_STRUCT__entry(
+		__array(char,		bdi, 32)
+		__field(unsigned long,	write_bw)
+		__field(unsigned long,	avg_write_bw)
+		__field(unsigned long,	dirty_rate)
+		__field(unsigned long,	dirty_ratelimit)
+		__field(unsigned long,	task_ratelimit)
+		__field(unsigned long,	balanced_dirty_ratelimit)
+	),
+
+	TP_fast_assign(
+		strlcpy(__entry->bdi, dev_name(bdi->dev), 32);
+		__entry->write_bw	= KBps(bdi->write_bandwidth);
+		__entry->avg_write_bw	= KBps(bdi->avg_write_bandwidth);
+		__entry->dirty_rate	= KBps(dirty_rate);
+		__entry->dirty_ratelimit = KBps(bdi->dirty_ratelimit);
+		__entry->task_ratelimit	= KBps(task_ratelimit);
+		__entry->balanced_dirty_ratelimit =
+					  KBps(bdi->balanced_dirty_ratelimit);
+	),
+
+	TP_printk("bdi %s: "
+		  "write_bw=%lu awrite_bw=%lu dirty_rate=%lu "
+		  "dirty_ratelimit=%lu task_ratelimit=%lu "
+		  "balanced_dirty_ratelimit=%lu",
+		  __entry->bdi,
+		  __entry->write_bw,		/* write bandwidth */
+		  __entry->avg_write_bw,	/* avg write bandwidth */
+		  __entry->dirty_rate,		/* bdi dirty rate */
+		  __entry->dirty_ratelimit,	/* base ratelimit */
+		  __entry->task_ratelimit, /* ratelimit with position control */
+		  __entry->balanced_dirty_ratelimit /* the balanced ratelimit */
+	)
+);
+
 DECLARE_EVENT_CLASS(writeback_congest_waited_template,
  
 	TP_PROTO(unsigned int usec_timeout, unsigned int usec_delayed),
@@ -875,6 +875,8 @@
  
 	bdi->dirty_ratelimit = max(dirty_ratelimit, 1UL);
 	bdi->balanced_dirty_ratelimit = balanced_dirty_ratelimit;
+
+	trace_bdi_dirty_ratelimit(bdi, dirty_rate, task_ratelimit);
 }
  
 void __bdi_update_bandwidth(struct backing_dev_info *bdi,
...	...	@@ -226,6 +226,51 @@
226	226	)
227	227	);
228	228
	229	+#define KBps(x) ((x) << (PAGE_SHIFT - 10))
	230	+
	231	+TRACE_EVENT(bdi_dirty_ratelimit,
	232	+
	233	+ TP_PROTO(struct backing_dev_info *bdi,
	234	+ unsigned long dirty_rate,
	235	+ unsigned long task_ratelimit),
	236	+
	237	+ TP_ARGS(bdi, dirty_rate, task_ratelimit),
	238	+
	239	+ TP_STRUCT__entry(
	240	+ __array(char, bdi, 32)
	241	+ __field(unsigned long, write_bw)
	242	+ __field(unsigned long, avg_write_bw)
	243	+ __field(unsigned long, dirty_rate)
	244	+ __field(unsigned long, dirty_ratelimit)
	245	+ __field(unsigned long, task_ratelimit)
	246	+ __field(unsigned long, balanced_dirty_ratelimit)
	247	+ ),
	248	+
	249	+ TP_fast_assign(
	250	+ strlcpy(__entry->bdi, dev_name(bdi->dev), 32);
	251	+ __entry->write_bw = KBps(bdi->write_bandwidth);
	252	+ __entry->avg_write_bw = KBps(bdi->avg_write_bandwidth);
	253	+ __entry->dirty_rate = KBps(dirty_rate);
	254	+ __entry->dirty_ratelimit = KBps(bdi->dirty_ratelimit);
	255	+ __entry->task_ratelimit = KBps(task_ratelimit);
	256	+ __entry->balanced_dirty_ratelimit =
	257	+ KBps(bdi->balanced_dirty_ratelimit);
	258	+ ),
	259	+
	260	+ TP_printk("bdi %s: "
	261	+ "write_bw=%lu awrite_bw=%lu dirty_rate=%lu "
	262	+ "dirty_ratelimit=%lu task_ratelimit=%lu "
	263	+ "balanced_dirty_ratelimit=%lu",
	264	+ __entry->bdi,
	265	+ __entry->write_bw, /* write bandwidth */
	266	+ __entry->avg_write_bw, /* avg write bandwidth */
	267	+ __entry->dirty_rate, /* bdi dirty rate */
	268	+ __entry->dirty_ratelimit, /* base ratelimit */
	269	+ __entry->task_ratelimit, /* ratelimit with position control */
	270	+ __entry->balanced_dirty_ratelimit /* the balanced ratelimit */
	271	+ )
	272	+);
	273	+
229	274	DECLARE_EVENT_CLASS(writeback_congest_waited_template,
230	275
231	276	TP_PROTO(unsigned int usec_timeout, unsigned int usec_delayed),
...	...	@@ -875,6 +875,8 @@
875	875
876	876	bdi->dirty_ratelimit = max(dirty_ratelimit, 1UL);
877	877	bdi->balanced_dirty_ratelimit = balanced_dirty_ratelimit;
	878	+
	879	+ trace_bdi_dirty_ratelimit(bdi, dirty_rate, task_ratelimit);
878	880	}
879	881
880	882	void __bdi_update_bandwidth(struct backing_dev_info *bdi,