GFS2: Add an AIL writeback tracepoint

Add a tracepoint for monitoring writeback of the AIL.

Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>

2 files changed, 30 insertions, 0 deletions

diff --git a/fs/gfs2/log.c b/fs/gfs2/log.c
index 03e00417061b..ad1f1887633f 100644
--- a/fs/gfs2/log.c
+++ b/fs/gfs2/log.c
@@ -144,6 +144,7 @@ void gfs2_ail1_flush(struct gfs2_sbd *sdp, struct writeback_control *wbc)
         struct list_head *head = &sdp->sd_ail1_list;
         struct gfs2_ail *ai;
 
+        trace_gfs2_ail_flush(sdp, wbc, 1);
         spin_lock(&sdp->sd_ail_lock);
         list_for_each_entry_reverse(ai, head, ai_list) {
                 if (wbc->nr_to_write <= 0)
@@ -151,6 +152,7 @@ void gfs2_ail1_flush(struct gfs2_sbd *sdp, struct writeback_control *wbc)
                 gfs2_ail1_start_one(sdp, wbc, ai); /* This may drop ail lock */
         }
         spin_unlock(&sdp->sd_ail_lock);
+        trace_gfs2_ail_flush(sdp, wbc, 0);
 }
 
 /**
diff --git a/fs/gfs2/trace_gfs2.h b/fs/gfs2/trace_gfs2.h
index 9133d0aaac26..5d07609ec57d 100644
--- a/fs/gfs2/trace_gfs2.h
+++ b/fs/gfs2/trace_gfs2.h
@@ -10,6 +10,7 @@
 #include <linux/buffer_head.h>
 #include <linux/dlmconstants.h>
 #include <linux/gfs2_ondisk.h>
+#include <linux/writeback.h>
 #include "incore.h"
 #include "glock.h"
 
@@ -320,6 +321,33 @@ TRACE_EVENT(gfs2_log_blocks,
                   MINOR(__entry->dev), __entry->blocks)
 );
 
+/* Writing back the AIL */
+TRACE_EVENT(gfs2_ail_flush,
+
+        TP_PROTO(const struct gfs2_sbd *sdp, const struct writeback_control *wbc, int start),
+
+        TP_ARGS(sdp, wbc, start),
+
+        TP_STRUCT__entry(
+                __field(        dev_t,  dev                     )
+                __field(        int, start                      )
+                __field(        int, sync_mode                  )
+                __field(        long, nr_to_write               )
+        ),
+
+        TP_fast_assign(
+                __entry->dev            = sdp->sd_vfs->s_dev;
+                __entry->start          = start;
+                __entry->sync_mode      = wbc->sync_mode;
+                __entry->nr_to_write    = wbc->nr_to_write;
+        ),
+
+        TP_printk("%u,%u ail flush %s %s %ld", MAJOR(__entry->dev),
+                  MINOR(__entry->dev), __entry->start ? "start" : "end",
+                  __entry->sync_mode == WB_SYNC_ALL ? "all" : "none",
+                  __entry->nr_to_write)
+);
+
 /* Section 3 - bmap
  *
  * Objectives: