Re: [PATCH 2/3] xfs: use per-filesystem I/O completion workqueues

[Christoph Hellwig <hch@xxxxxxxxxxxxx>]

On Thu, Aug 25, 2011 at 10:48:11AM +1000, Dave Chinner wrote:
> The only issue I see with this is that it brings back per-filesystem
> workqueue threads. Because all the workqueues are defined with
> MEM_RECLAIM, there is a rescuer thread per workqueue that is used
> when the CWMQ cannot allocate memory to queue the work to the
> appropriate per-cpu queue.

Not much we can do about it.

> If we are going to block here, then we probably should increase the
> per-cpu concurrency of the work queue so that we can continue to
> process other ioends while this one is blocked.

True.