linux-toradex.git/drivers/block/drbd/drbd_int.h, branch v3.18.10

drbd: Get rid of the __no_warn and __cond_lock macros

2014-09-11T14:41:29+00:00

These macros can easily be replaced with its definition.

Signed-off-by: Philipp Reisner 
Signed-off-by: Lars Ellenberg 
Signed-off-by: Jens Axboe

drbd: Use consistent names for all the bi_end_io callbacks

2014-09-11T14:41:29+00:00

Now they follow the _endio naming sheme.

Signed-off-by: Philipp Reisner 
Signed-off-by: Lars Ellenberg 
Signed-off-by: Jens Axboe

drbd: Use better variable names

2014-09-11T14:41:29+00:00

Rename local variable 'ds' to 'disk_state' or 'data_size'.
'dgs' to 'digest_size'

Signed-off-by: Philipp Reisner 
Signed-off-by: Lars Ellenberg 
Signed-off-by: Jens Axboe

drbd: debugfs: add callback_history

2014-07-10T16:35:18+00:00

Add a per-connection worker thread callback_history
with timing details, call site and callback function.

Signed-off-by: Philipp Reisner 
Signed-off-by: Lars Ellenberg

drbd: debugfs: Add in_flight_summary

2014-07-10T16:35:17+00:00

* Add details about pending meta data operations to in_flight_summary.

* Report number of requests waiting for activity log transactions.

* timing details of peer_requests to in_flight_summary.

* FLUSH details
  DRBD devides the incoming request stream into "epochs",
  in which peers are allowed to re-order writes independendly.

  These epochs are separated by P_BARRIER on the replication link.
  Such barrier packets, depending on configuration, may cause
  the receiving side to drain the lower level device request queues
  and call blkdev_issue_flush().

  This is known to be an other major source of latency in DRBD.

  Track timing details of calls to blkdev_issue_flush(),
  and add them to in_flight_summary.

* data socket stats
  To be able to diagnose bottlenecks and root causes of "slow" IO on DRBD,
  it is useful to see network buffer stats along with the timing details of
  requests, peer requests, and meta data IO.

* pending bitmap IO timing details to in_flight_summary.

Signed-off-by: Philipp Reisner 
Signed-off-by: Lars Ellenberg

drbd: debugfs: add basic hierarchy

2014-07-10T16:35:16+00:00

Add new debugfs hierarchy /sys/kernel/debug/
  drbd/
    resources/
      $resource_name/connections/peer/$volume_number/
      $resource_name/volumes/$volume_number/
    minors/$minor_number -> ../resources/$resource_name/volumes/$volume_number/

Followup commits will populate this hierarchy with files containing
statistics, diagnostic information and some attribute data.

Signed-off-by: Philipp Reisner 
Signed-off-by: Lars Ellenberg

drbd: track details of bitmap IO

2014-07-10T16:35:15+00:00

Track start and submit time of bitmap operations, and
add pending bitmap IO contexts to a new pending_bitmap_io list.

Signed-off-by: Philipp Reisner 
Signed-off-by: Lars Ellenberg

drbd: track timing details of peer_requests

2014-07-10T16:35:14+00:00

To be able to present timing details in debugfs,
we need to track preparation/submit times of peer requests.

Track peer request flags early,
before they are put on the epoch_entry lists.

Waiting for activity log transactions may be a major latency factor.
We want to be able to present the peer_request state accurately in
debugfs, and what it is waiting for.

Consistently mark/unmark peer requests with EE_CALL_AL_COMPLETE_IO.
Set it only *after* calling drbd_al_begin_io(),
clear it as soon as we call drbd_al_complete_io().

Signed-off-by: Philipp Reisner 
Signed-off-by: Lars Ellenberg

drbd: improve throttling decisions of background resynchronisation

2014-07-10T16:35:13+00:00

Background resynchronisation does some "side-stepping", or throttles
itself, if it detects application IO activity, and the current resync
rate estimate is above the configured "cmin-rate".

What was not detected: if there is no application IO,
because it blocks on activity log transactions.

Introduce a new atomic_t ap_actlog_cnt, tracking such blocked requests,
and count non-zero as application IO activity.
This counter is exposed at proc_details level 2 and above.

Also make sure to release the currently locked resync extent
if we side-step due to such voluntary throttling.

Signed-off-by: Philipp Reisner 
Signed-off-by: Lars Ellenberg

drbd: add caching oldest request pointers for replication stages

2014-07-10T16:35:12+00:00

A request that is to be shipped to the peer goes through a few stages:
- queued
- sent, waiting for ack
- ack received, waiting for "barrier ack", which is re-order epoch being
  closed on the peer by acknowledging a "cache flush" equivalent
  on the lower level device.

In the later two stages, depending on protocol, we may have already
completed this request to the upper layers, so it won't be found anymore
on device->pending_master_completion[] lists.

Track the oldest request yet to be sent (req_next), the oldest not yet
acknowledged (req_ack_pending) and the oldest "still waiting for
something from the peer" (req_not_net_done), doing short list walks on
the transfer log to find the next pending one whenever such a request
makes progress.

Now we have a fast way to look up the oldest requests,
don't do a transfer log walk every time.

Signed-off-by: Philipp Reisner 
Signed-off-by: Lars Ellenberg