3 files changed, 124 insertions, 8 deletions

diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
index c8471b3ddccf..73acab4dc2b7 100644
--- a/fs/fs-writeback.c
+++ b/fs/fs-writeback.c
@@ -26,15 +26,9 @@
 #include <linux/blkdev.h>
 #include <linux/backing-dev.h>
 #include <linux/buffer_head.h>
+#include <linux/tracepoint.h>
 #include "internal.h"
 
-#define inode_to_bdi(inode)     ((inode)->i_mapping->backing_dev_info)
-
-/*
- * We don't actually have pdflush, but this one is exported though /proc...
- */
-int nr_pdflush_threads;
-
 /*
  * Passed into wb_writeback(), essentially a subset of writeback_control
  */
@@ -50,6 +44,21 @@ struct wb_writeback_work {
         struct completion *done;        /* set if the caller waits */
 };
 
+/*
+ * Include the creation of the trace points after defining the
+ * wb_writeback_work structure so that the definition remains local to this
+ * file.
+ */
+#define CREATE_TRACE_POINTS
+#include <trace/events/writeback.h>
+
+#define inode_to_bdi(inode)     ((inode)->i_mapping->backing_dev_info)
+
+/*
+ * We don't actually have pdflush, but this one is exported though /proc...
+ */
+int nr_pdflush_threads;
+
 /**
  * writeback_in_progress - determine whether there is writeback in progress
  * @bdi: the device's backing_dev_info structure.
@@ -65,6 +74,8 @@ int writeback_in_progress(struct backing_dev_info *bdi)
 static void bdi_queue_work(struct backing_dev_info *bdi,
                 struct wb_writeback_work *work)
 {
+        trace_writeback_queue(bdi, work);
+
         spin_lock(&bdi->wb_lock);
         list_add_tail(&work->list, &bdi->work_list);
         spin_unlock(&bdi->wb_lock);
@@ -74,6 +85,7 @@ static void bdi_queue_work(struct backing_dev_info *bdi,
          * it gets created and wakes up, we'll run this work.
          */
         if (unlikely(!bdi->wb.task)) {
+                trace_writeback_nothread(bdi, work);
                 wake_up_process(default_backing_dev_info.wb.task);
         } else {
                 struct bdi_writeback *wb = &bdi->wb;
@@ -95,8 +107,10 @@ __bdi_start_writeback(struct backing_dev_info *bdi, long nr_pages,
          */
         work = kzalloc(sizeof(*work), GFP_ATOMIC);
         if (!work) {
-                if (bdi->wb.task)
+                if (bdi->wb.task) {
+                        trace_writeback_nowork(bdi);
                         wake_up_process(bdi->wb.task);
+                }
                 return;
         }
 
@@ -751,6 +765,8 @@ long wb_do_writeback(struct bdi_writeback *wb, int force_wait)
                 if (force_wait)
                         work->sync_mode = WB_SYNC_ALL;
 
+                trace_writeback_exec(bdi, work);
+
                 wrote += wb_writeback(wb, work);
 
                 /*
@@ -805,9 +821,13 @@ int bdi_writeback_thread(void *data)
         smp_mb__after_clear_bit();
         wake_up_bit(&bdi->state, BDI_pending);
 
+        trace_writeback_thread_start(bdi);
+
         while (!kthread_should_stop()) {
                 pages_written = wb_do_writeback(wb, 0);
 
+                trace_writeback_pages_written(pages_written);
+
                 if (pages_written)
                         last_active = jiffies;
                 else if (wait_jiffies != -1UL) {
@@ -845,6 +865,8 @@ int bdi_writeback_thread(void *data)
          */
         if (!list_empty(&bdi->work_list))
                 wb_do_writeback(wb, 1);
+
+        trace_writeback_thread_stop(bdi);
         return 0;
 }
 
diff --git a/include/trace/events/writeback.h b/include/trace/events/writeback.h
new file mode 100644
index 000000000000..562fcae10d9d
--- /dev/null
+++ b/include/trace/events/writeback.h
@@ -0,0 +1,91 @@
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM writeback
+
+#if !defined(_TRACE_WRITEBACK_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_WRITEBACK_H
+
+#include <linux/backing-dev.h>
+#include <linux/writeback.h>
+
+struct wb_writeback_work;
+
+DECLARE_EVENT_CLASS(writeback_work_class,
+        TP_PROTO(struct backing_dev_info *bdi, struct wb_writeback_work *work),
+        TP_ARGS(bdi, work),
+        TP_STRUCT__entry(
+                __array(char, name, 32)
+                __field(long, nr_pages)
+                __field(dev_t, sb_dev)
+                __field(int, sync_mode)
+                __field(int, for_kupdate)
+                __field(int, range_cyclic)
+                __field(int, for_background)
+        ),
+        TP_fast_assign(
+                strncpy(__entry->name, dev_name(bdi->dev), 32);
+                __entry->nr_pages = work->nr_pages;
+                __entry->sb_dev = work->sb ? work->sb->s_dev : 0;
+                __entry->sync_mode = work->sync_mode;
+                __entry->for_kupdate = work->for_kupdate;
+                __entry->range_cyclic = work->range_cyclic;
+                __entry->for_background = work->for_background;
+        ),
+        TP_printk("bdi %s: sb_dev %d:%d nr_pages=%ld sync_mode=%d "
+                  "kupdate=%d range_cyclic=%d background=%d",
+                  __entry->name,
+                  MAJOR(__entry->sb_dev), MINOR(__entry->sb_dev),
+                  __entry->nr_pages,
+                  __entry->sync_mode,
+                  __entry->for_kupdate,
+                  __entry->range_cyclic,
+                  __entry->for_background
+        )
+);
+#define DEFINE_WRITEBACK_WORK_EVENT(name) \
+DEFINE_EVENT(writeback_work_class, name, \
+        TP_PROTO(struct backing_dev_info *bdi, struct wb_writeback_work *work), \
+        TP_ARGS(bdi, work))
+DEFINE_WRITEBACK_WORK_EVENT(writeback_nothread);
+DEFINE_WRITEBACK_WORK_EVENT(writeback_queue);
+DEFINE_WRITEBACK_WORK_EVENT(writeback_exec);
+
+TRACE_EVENT(writeback_pages_written,
+        TP_PROTO(long pages_written),
+        TP_ARGS(pages_written),
+        TP_STRUCT__entry(
+                __field(long,           pages)
+        ),
+        TP_fast_assign(
+                __entry->pages          = pages_written;
+        ),
+        TP_printk("%ld", __entry->pages)
+);
+
+DECLARE_EVENT_CLASS(writeback_class,
+        TP_PROTO(struct backing_dev_info *bdi),
+        TP_ARGS(bdi),
+        TP_STRUCT__entry(
+                __array(char, name, 32)
+        ),
+        TP_fast_assign(
+                strncpy(__entry->name, dev_name(bdi->dev), 32);
+        ),
+        TP_printk("bdi %s",
+                  __entry->name
+        )
+);
+#define DEFINE_WRITEBACK_EVENT(name) \
+DEFINE_EVENT(writeback_class, name, \
+        TP_PROTO(struct backing_dev_info *bdi), \
+        TP_ARGS(bdi))
+
+DEFINE_WRITEBACK_EVENT(writeback_nowork);
+DEFINE_WRITEBACK_EVENT(writeback_bdi_register);
+DEFINE_WRITEBACK_EVENT(writeback_bdi_unregister);
+DEFINE_WRITEBACK_EVENT(writeback_thread_start);
+DEFINE_WRITEBACK_EVENT(writeback_thread_stop);
+
+#endif /* _TRACE_WRITEBACK_H */
+
+/* This part must be outside protection */
+#include <trace/define_trace.h>
diff --git a/mm/backing-dev.c b/mm/backing-dev.c
index bceac647e4d1..ac78a3336181 100644
--- a/mm/backing-dev.c
+++ b/mm/backing-dev.c
@@ -10,6 +10,7 @@
 #include <linux/module.h>
 #include <linux/writeback.h>
 #include <linux/device.h>
+#include <trace/events/writeback.h>
 
 static atomic_long_t bdi_seq = ATOMIC_LONG_INIT(0);
 
@@ -518,6 +519,7 @@ int bdi_register(struct backing_dev_info *bdi, struct device *parent,
 
         bdi_debug_register(bdi, dev_name(dev));
         set_bit(BDI_registered, &bdi->state);
+        trace_writeback_bdi_register(bdi);
 exit:
         return ret;
 }
@@ -578,6 +580,7 @@ static void bdi_prune_sb(struct backing_dev_info *bdi)
 void bdi_unregister(struct backing_dev_info *bdi)
 {
         if (bdi->dev) {
+                trace_writeback_bdi_unregister(bdi);
                 bdi_prune_sb(bdi);
 
                 if (!bdi_cap_flush_forker(bdi))