device-mapper update for 2.6.25
On Thu, Feb 07, 2008 at 07:04:47PM -0800, Andrew Morton wrote:
> On Fri, 8 Feb 2008 02:45:32 +0000 Alasdair G Kergon <email@example.com> wrote:
> > dm: move deferred bio flushing to workqueue
> To my unpracticed eye this one looks fairly fundamental. Unfortunately the
> Add a single-thread workqueue for each mapped device and move flushing
> of the lists of pushback and deferred bios to this new workqueue.
> tells us nothing of the reasons for this change. (It should have done so!)
> It _looks_ pretty unscalable. Perhaps these deferred BIOs don't happen
> very often?
Indeed - it's a rare occurrence - happens when the dm device is
suspended/resumed which usually means it was being reconfigured by something in
It's the first patch of a series that will provide barrier support (slated for
The appearance of all these workqueues in dm goes back to this old change:
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