writeback: show raw dirtied_when in trace writeback_single_inode

Save inode->dirtied_when in the raw trace output for reliable scripting,
and to also show in formatted output the relative age in seconds for
easy human reading.

CC: Jan Kara <jack@suse.cz>
Acked-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>

diff --git a/include/trace/events/writeback.h b/include/trace/events/writeback.h
index 6bca4cc..5f17270 100644 (file)
--- a/include/trace/events/writeback.h
+++ b/include/trace/events/writeback.h
@@ -298,7 +298,7 @@ DECLARE_EVENT_CLASS(writeback_single_inode_template,
                __array(char, name, 32)
                __field(unsigned long, ino)
                __field(unsigned long, state)
-               __field(unsigned long, age)
+               __field(unsigned long, dirtied_when)
                __field(unsigned long, writeback_index)
                __field(long, nr_to_write)
                __field(unsigned long, wrote)
@@ -309,19 +309,19 @@ DECLARE_EVENT_CLASS(writeback_single_inode_template,
                        dev_name(inode->i_mapping->backing_dev_info->dev), 32);
                __entry->ino            = inode->i_ino;
                __entry->state          = inode->i_state;
-               __entry->age            = (jiffies - inode->dirtied_when) *
-                                                               1000 / HZ;
+               __entry->dirtied_when   = inode->dirtied_when;
                __entry->writeback_index = inode->i_mapping->writeback_index;
                __entry->nr_to_write    = nr_to_write;
                __entry->wrote          = nr_to_write - wbc->nr_to_write;
        ),
 
-       TP_printk("bdi %s: ino=%lu state=%s age=%lu "
+       TP_printk("bdi %s: ino=%lu state=%s dirtied_when=%lu age=%lu "
                  "index=%lu to_write=%ld wrote=%lu",
                  __entry->name,
                  __entry->ino,
                  show_inode_state(__entry->state),
-                 __entry->age,
+                 __entry->dirtied_when,
+                 (jiffies - __entry->dirtied_when) / HZ,
                  __entry->writeback_index,
                  __entry->nr_to_write,
                  __entry->wrote