tree 5ba59239707b467095a84e743724f29085eb8858
parent 8b6bf747d70e5bac1a34c8fd773230e1cfdd7546
author Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> 1303837079 -0400
committer Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> 1303837292 -0400

xen/blkback: Move the plugging/unplugging to a higher level.

We used to the plug/unplug on the submit_bio. But that means
if within a stream of WRITE, WRITE, WRITE,...,WRITE we have
one READ, it could stall the pipeline (as the 'submio_bio'
could trigger the unplug_fnc to be called and stall/sync
when doing the READ). Instead we want to move the unplugging
when the whole (or as a much as possible) ring buffer has been
processed. This also eliminates us doing plug/unplug for
each request.

Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>