On 1/21/22 5:38 AM, Dylan Yudaken wrote:
> In some cases io_rsrc_ref_quiesce will call io_rsrc_node_switch_start,
> and then immediately flush the delayed work queue &ctx->rsrc_put_work.
>
> However the percpu_ref_put does not immediately destroy the node, it
> will be called asynchronously via RCU. That ends up with
> io_rsrc_node_ref_zero only being called after rsrc_put_work has been
> flushed, and so the process ends up sleeping for 1 second unnecessarily.
>
> This patch executes the put code immediately if we are busy
> quiescing.
Looks good to me, and as far as I can tell, this bug was introduced by:
commit 4a38aed2a0a729ccecd84dca5b76d827b9e1294d
Author: Jens Axboe <axboe@xxxxxxxxx>
Date: Thu May 14 17:21:15 2020 -0600
io_uring: batch reap of dead file registrations
so I'll add a fixes line to that effect to the commit. Thanks!
--
Jens Axboe
