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 <[email protected]> --- 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
