Add a tracepoint to dax_writeback_one(), following the same logging
conventions as the rest of DAX.
Here is an example range writeback which ends up flushing one PMD and one
PTE:
test-1265 [003] .... 496.615250: dax_writeback_range: dev 259:0 ino 0x1003
pgoff 0x0-0x7ffffffffffff
test-1265 [003] .... 496.616263: dax_writeback_one: dev 259:0 ino 0x1003
pgoff 0x0 pglen 0x200
test-1265 [003] .... 496.616270: dax_writeback_one: dev 259:0 ino 0x1003
pgoff 0x305 pglen 0x1
test-1265 [003] .... 496.616272: dax_writeback_range_done: dev 259:0 ino
0x1003 pgoff 0x0-0x7ffffffffffff
Signed-off-by: Ross Zwisler <ross.zwisler@xxxxxxxxxxxxxxx>
---
fs/dax.c | 1 +
include/trace/events/fs_dax.h | 24 ++++++++++++++++++++++++
2 files changed, 25 insertions(+)
diff --git a/fs/dax.c b/fs/dax.c
index 7ca1989..d340389 100644
--- a/fs/dax.c
+++ b/fs/dax.c
@@ -843,6 +843,7 @@ static int dax_writeback_one(struct block_device *bdev,
spin_lock_irq(&mapping->tree_lock);
radix_tree_tag_clear(page_tree, index, PAGECACHE_TAG_DIRTY);
spin_unlock_irq(&mapping->tree_lock);
+ trace_dax_writeback_one(mapping->host, index, dax.size >> PAGE_SHIFT);
unmap:
dax_unmap_atomic(bdev, &dax);
put_locked_mapping_entry(mapping, index, entry);
diff --git a/include/trace/events/fs_dax.h b/include/trace/events/fs_dax.h
index 9afe8c8..292a471 100644
--- a/include/trace/events/fs_dax.h
+++ b/include/trace/events/fs_dax.h
@@ -226,6 +226,30 @@ DEFINE_EVENT(dax_writeback_range_class, name, \
DEFINE_WRITEBACK_RANGE_EVENT(dax_writeback_range);
DEFINE_WRITEBACK_RANGE_EVENT(dax_writeback_range_done);
+TRACE_EVENT(dax_writeback_one,
+ TP_PROTO(struct inode *inode, pgoff_t pgoff, pgoff_t pglen),
+ TP_ARGS(inode, pgoff, pglen),
+ TP_STRUCT__entry(
+ __field(unsigned long, ino)
+ __field(pgoff_t, pgoff)
+ __field(pgoff_t, pglen)
+ __field(dev_t, dev)
+ ),
+ TP_fast_assign(
+ __entry->dev = inode->i_sb->s_dev;
+ __entry->ino = inode->i_ino;
+ __entry->pgoff = pgoff;
+ __entry->pglen = pglen;
+ ),
+ TP_printk("dev %d:%d ino %#lx pgoff %#lx pglen %#lx",
+ MAJOR(__entry->dev),
+ MINOR(__entry->dev),
+ __entry->ino,
+ __entry->pgoff,
+ __entry->pglen
+ )
+)
+
#endif /* _TRACE_FS_DAX_H */
/* This part must be outside protection */
--
2.9.3
