xen/blkback: Don't let in-flight requests defer pending ones.
commitb4726a9df270859898e254b6eee67a28f38b34d3
authorDaniel Stodden <daniel.stodden@citrix.com>
Sat, 28 May 2011 20:21:10 +0000 (28 13:21 -0700)
committerKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Thu, 30 Jun 2011 16:48:06 +0000 (30 12:48 -0400)
tree2512fcce88e4ad97ea1068864d716fd105d86c39
parent2b727c6300b49352f80f63704bb50c256949e95e
xen/blkback: Don't let in-flight requests defer pending ones.

Running RING_FINAL_CHECK_FOR_REQUESTS from make_response is a bad
idea. It means that in-flight I/O is essentially blocking continued
batches. This essentially kills throughput on frontends which unplug
(or even just notify) early and rightfully assume addtional requests
will be picked up on time, not synchronously.

Signed-off-by: Daniel Stodden <daniel.stodden@citrix.com>
[v1: Rebased and fixed compile problems]
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
drivers/block/xen-blkback/blkback.c