mbox series

[RFC,0/9] ext4: Improve FC trace events and discuss one FC failure

Message ID cover.1645558375.git.riteshh@linux.ibm.com
Headers show
Series ext4: Improve FC trace events and discuss one FC failure | expand

Message

Ritesh Harjani Feb. 22, 2022, 8:34 p.m. UTC 
Hello,

Sending this RFC out for getting some review comments/suggestions on the
problem listed in this cover letter. It would be helpful if someone has any
pointers around these.

1. Patch-2 fixes the problem reported by Steven about dereferencing pointers from
   the ring buffer [1].
	One of the problem in this patch which I might need some help is, how to
	expose EXT4_FC_REASON_MAX enum for
	+	__array(unsigned int, fc_ineligible_rc, EXT4_FC_REASON_MAX)

	My observation is that this trace_event is correctly printing the array
	values when called from cat /sys/kernel/debug/tracing/trace_pipe.

	But when I am using perf record -e ext4:ext4_fc_stats to record these trace
	events, I am seeing the array values to be all 0.

	Do you know what will be the right and easy way to fix above, so that this works
	properly for perf tools too? And we should be able to backport this too.

2. Patch-9 discusses one of the problem where FC might miss to track/commit
   inode's update. This also needs some discussion. I have added my observations
   on the commit log of patch-9 itself.

3. Remaining are FC trace event improvement patches, which I found useful while
   debugging some of the recent fast_commit issues.

Also a careful review of patches is always helpful :)


[1]: https://lore.kernel.org/linux-ext4/20220221160916.333e6491@rorschach.local.home/T/#u

Ritesh Harjani (9):
  ext4: Remove unused enum EXT4_FC_COMMIT_FAILED
  ext4: Fix ext4_fc_stats trace point
  ext4: Add couple of more fast_commit tracepoints
  ext4: Do not call FC trace event if FS does not support FC
  ext4: Add commit_tid info in jbd debug log
  ext4: Add commit tid info in ext4_fc_commit_start/stop trace events
  ext4: Fix remaining two trace events to use same printk convention
  ext4: Convert ext4_fc_track_dentry type events to use event class
  ext4: fast_commit missing tracking updates to a file

 fs/ext4/fast_commit.c       |  30 +++--
 fs/ext4/fast_commit.h       |   1 -
 include/trace/events/ext4.h | 229 +++++++++++++++++++++++++-----------
 3 files changed, 182 insertions(+), 78 deletions(-)

--
2.31.1

Comments

Theodore Ts'o March 9, 2022, 5:48 p.m. UTC | #1 
Ritesh,

Were you going to be sending a revised version of this patch series?

Thanks!

					- Ted
Ritesh Harjani March 10, 2022, 1:22 a.m. UTC | #2 
On 22/03/09 12:48PM, Theodore Ts'o wrote:
> Ritesh,
>
> Were you going to be sending a revised version of this patch series?

Hello Ted,

Due to some unexpected guests at home, I was on leave since last weekend.
I am starting to work from today. Let me work on the revised version of this
patch series. I will try to complete it before end of day i.e. before
our call.


-ritesh