Re: [PATCH 08/13] bdi: Shutdown writeback on all cgwbs in cgwb_bdi_destroy()

Hello,

On Tue, Feb 21, 2017 at 06:09:53PM +0100, Jan Kara wrote:

Currently we waited for all cgwbs to get freed in cgwb_bdi_destroy()
which also means that writeback has been shutdown on them. Since this
wait is going away, directly shutdown writeback on cgwbs from
cgwb_bdi_destroy() to avoid live writeback structures after
bdi_unregister() has finished.

Hmmm... the only thing which is a bit bothering is that after removing
the shutdown from release_workfn this would make the final flushing
sequential, one cgwb at a time, which in certain cases can take an
unnecessarily long time.  It's not a correctness issue tho and if it
becomes a problem we can deal with it by splitting wb_shutdown() into
two pieces - the unregistration / issuing of the work items, and the
flushing of those.  Other than that, looks good to me.

Acked-by: Tejun Heo <tj@kernel.org>

Thanks.

-- 
tejun