writeback: Initial tracing support
authorDave Chinner <david@fromorbit.com>
Wed, 7 Jul 2010 03:24:06 +0000 (13:24 +1000)
committerJens Axboe <jaxboe@fusionio.com>
Sat, 7 Aug 2010 16:24:23 +0000 (18:24 +0200)
commit455b2864686d3591b3b2f39eb46290c95f76471f
treeb88059e3691fc5ad4491518e9eb1f1f2ba21711a
parenta89f5c899db3c6be4bb426e4efb72ecee29a93b5
writeback: Initial tracing support

Trace queue/sched/exec parts of the writeback loop. This provides
insight into when and why flusher threads are scheduled to run. e.g
a sync invocation leaves traces like:

     sync-[...]: writeback_queue: bdi 8:0: sb_dev 8:1 nr_pages=7712 sync_mode=0 kupdate=0 range_cyclic=0 background=0
flush-8:0-[...]: writeback_exec: bdi 8:0: sb_dev 8:1 nr_pages=7712 sync_mode=0 kupdate=0 range_cyclic=0 background=0

This also lays the foundation for adding more writeback tracing to
provide deeper insight into the whole writeback path.

The original tracing code is from Jens Axboe, though this version is
a rewrite as a result of the code being traced changing
significantly.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
fs/fs-writeback.c
include/trace/events/writeback.h [new file with mode: 0644]
mm/backing-dev.c