[dm-devel] Re: [git pull] device-mapper update for 2.6.25

[Andrew Morton <akpm linux-foundation org>]

On Fri, 8 Feb 2008 02:45:32 +0000 Alasdair G Kergon <agk redhat com> wrote:

>       dm: move deferred bio flushing to workqueue

To my unpracticed eye this one looks fairly fundamental.  Unfortunately the
changelog:

  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?