Re: [PATCHv4 14/14] writeback: add new tracepoints

[Christoph Hellwig]

On Fri, Jul 23, 2010 at 06:05:54PM +0300, Artem Bityutskiy wrote:
> From: Artem Bityutskiy <Artem.Bityutskiy@xxxxxxxxx>
> 
> Add 2 new trace points to the periodic write-back wake up case, just like we do
> in the 'bdi_queue_work()' function. Namely, introduce:
> 
> 1. trace_writeback_wakeup(bdi)
> 2. trace_writeback_wakeup_nothread(bdi)
> 
> The first event is triggered every time we wake up a bdi thread to start
> periodic background write-out. The second event is triggered only when the bdi
> thread does not exist and should be created by the forker thread.
> 
> This patch was suggested by Dave Chinner <david@xxxxxxxxxxxxx>

As mentioned before doing the wakeup just for the case where we
really wake up the flusher thead is much better.  It's not 100%
clear for bdi_queue_work as we queue the work in either case, but
I'd prefer to fix that one up as well (not in your series anyway)

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