3 files changed, 73 insertions, 0 deletions

diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
index 73acab4dc2b7..bf10cbf379dd 100644
--- a/fs/fs-writeback.c
+++ b/fs/fs-writeback.c
@@ -656,10 +656,14 @@ static long wb_writeback(struct bdi_writeback *wb,
                 wbc.more_io = 0;
                 wbc.nr_to_write = MAX_WRITEBACK_PAGES;
                 wbc.pages_skipped = 0;
+
+                trace_wbc_writeback_start(&wbc, wb->bdi);
                 if (work->sb)
                         __writeback_inodes_sb(work->sb, wb, &wbc);
                 else
                         writeback_inodes_wb(wb, &wbc);
+                trace_wbc_writeback_written(&wbc, wb->bdi);
+
                 work->nr_pages -= MAX_WRITEBACK_PAGES - wbc.nr_to_write;
                 wrote += MAX_WRITEBACK_PAGES - wbc.nr_to_write;
 
@@ -687,6 +691,7 @@ static long wb_writeback(struct bdi_writeback *wb,
                 if (!list_empty(&wb->b_more_io))  {
                         inode = list_entry(wb->b_more_io.prev,
                                                 struct inode, i_list);
+                        trace_wbc_writeback_wait(&wbc, wb->bdi);
                         inode_wait_for_writeback(inode);
                 }
                 spin_unlock(&inode_lock);
diff --git a/include/trace/events/writeback.h b/include/trace/events/writeback.h
index 562fcae10d9d..0be26acae064 100644
--- a/include/trace/events/writeback.h
+++ b/include/trace/events/writeback.h
@@ -85,6 +85,70 @@ DEFINE_WRITEBACK_EVENT(writeback_bdi_unregister);
 DEFINE_WRITEBACK_EVENT(writeback_thread_start);
 DEFINE_WRITEBACK_EVENT(writeback_thread_stop);
 
+DECLARE_EVENT_CLASS(wbc_class,
+        TP_PROTO(struct writeback_control *wbc, struct backing_dev_info *bdi),
+        TP_ARGS(wbc, bdi),
+        TP_STRUCT__entry(
+                __array(char, name, 32)
+                __field(long, nr_to_write)
+                __field(long, pages_skipped)
+                __field(int, sync_mode)
+                __field(int, nonblocking)
+                __field(int, encountered_congestion)
+                __field(int, for_kupdate)
+                __field(int, for_background)
+                __field(int, for_reclaim)
+                __field(int, range_cyclic)
+                __field(int, more_io)
+                __field(unsigned long, older_than_this)
+                __field(long, range_start)
+                __field(long, range_end)
+        ),
+
+        TP_fast_assign(
+                strncpy(__entry->name, dev_name(bdi->dev), 32);
+                __entry->nr_to_write    = wbc->nr_to_write;
+                __entry->pages_skipped  = wbc->pages_skipped;
+                __entry->sync_mode      = wbc->sync_mode;
+                __entry->for_kupdate    = wbc->for_kupdate;
+                __entry->for_background = wbc->for_background;
+                __entry->for_reclaim    = wbc->for_reclaim;
+                __entry->range_cyclic   = wbc->range_cyclic;
+                __entry->more_io        = wbc->more_io;
+                __entry->older_than_this = wbc->older_than_this ?
+                                                *wbc->older_than_this : 0;
+                __entry->range_start    = (long)wbc->range_start;
+                __entry->range_end      = (long)wbc->range_end;
+        ),
+
+        TP_printk("bdi %s: towrt=%ld skip=%ld mode=%d kupd=%d "
+                "bgrd=%d reclm=%d cyclic=%d more=%d older=0x%lx "
+                "start=0x%lx end=0x%lx",
+                __entry->name,
+                __entry->nr_to_write,
+                __entry->pages_skipped,
+                __entry->sync_mode,
+                __entry->for_kupdate,
+                __entry->for_background,
+                __entry->for_reclaim,
+                __entry->range_cyclic,
+                __entry->more_io,
+                __entry->older_than_this,
+                __entry->range_start,
+                __entry->range_end)
+)
+
+#define DEFINE_WBC_EVENT(name) \
+DEFINE_EVENT(wbc_class, name, \
+        TP_PROTO(struct writeback_control *wbc, struct backing_dev_info *bdi), \
+        TP_ARGS(wbc, bdi))
+DEFINE_WBC_EVENT(wbc_writeback_start);
+DEFINE_WBC_EVENT(wbc_writeback_written);
+DEFINE_WBC_EVENT(wbc_writeback_wait);
+DEFINE_WBC_EVENT(wbc_balance_dirty_start);
+DEFINE_WBC_EVENT(wbc_balance_dirty_written);
+DEFINE_WBC_EVENT(wbc_balance_dirty_wait);
+
 #endif /* _TRACE_WRITEBACK_H */
 
 /* This part must be outside protection */
diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index 37498ef61548..d556cd829af6 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -34,6 +34,7 @@
 #include <linux/syscalls.h>
 #include <linux/buffer_head.h>
 #include <linux/pagevec.h>
+#include <trace/events/writeback.h>
 
 /*
  * After a CPU has dirtied this many pages, balance_dirty_pages_ratelimited
@@ -535,11 +536,13 @@ static void balance_dirty_pages(struct address_space *mapping,
                  * threshold otherwise wait until the disk writes catch
                  * up.
                  */
+                trace_wbc_balance_dirty_start(&wbc, bdi);
                 if (bdi_nr_reclaimable > bdi_thresh) {
                         writeback_inodes_wb(&bdi->wb, &wbc);
                         pages_written += write_chunk - wbc.nr_to_write;
                         get_dirty_limits(&background_thresh, &dirty_thresh,
                                        &bdi_thresh, bdi);
+                        trace_wbc_balance_dirty_written(&wbc, bdi);
                 }
 
                 /*
@@ -565,6 +568,7 @@ static void balance_dirty_pages(struct address_space *mapping,
                 if (pages_written >= write_chunk)
                         break;          /* We've done our duty */
 
+                trace_wbc_balance_dirty_wait(&wbc, bdi);
                 __set_current_state(TASK_INTERRUPTIBLE);
                 io_schedule_timeout(pause);