[ovs-dev] [PATCH ovs v3] ovsdb idl: Try committing the pending txn in ovsdb_idl_loop_run.

[Ben Pfaff]

On Fri, Jun 05, 2020 at 02:00:29PM +0530, numans at ovn.org wrote:
> From: Numan Siddique <numans at ovn.org>
> 
> The function ovsdb_idl_loop_run(), after calling ovsdb_idl_run(),
> returns a transaction object (of type 'struct ovsdb_idl_txn').
> The returned transaction object can be NULL if there is a pending
> transaction (loop->committing_txn) in the idl loop object.
> 
> Normally the clients of idl library, first call ovsdb_idl_loop_run(),
> then do their own processing and create any idl transactions during
> this processing and then finally call ovsdb_idl_loop_commit_and_wait().
> 
> If ovsdb_idl_loop_run() returns NULL transaction object, then much
> of the processing done by the client gets wasted as in the case
> of ovn-controller.
> 
> The client (in this case ovn-controller), can skip the processing
> and instead call ovsdb_idl_loop_commit_and_wait() if the transaction
> oject is NULL. But ovn-controller uses IDL tracking and it may
> loose the tracked changes in that run.
> 
> This patch tries to improve this scenario, by checking if the
> pending transaction can be committed in the ovsdb_idl_loop_run()
> itself and if the pending transaction is cleared (because of the
> response messages from ovsdb-server due to a transaction message
> in the previous run), ovsdb_idl_loop_run() can return a valid
> transaction object.
> 
> CC: Han Zhou <hzhou at ovn.org>
> Signed-off-by: Numan Siddique <numans at ovn.org>

This seems reasonable to me, so I committed it.

It would have been nice to have a report on how much difference it made,
though.