From: Jeremy Fitzhardinge Date: Thu, 22 Jul 2010 21:17:00 +0000 (-0700) Subject: xen/blkfront: use tagged queuing for barriers X-Git-Tag: v2.6.36-rc1~288^2~32 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=4dab46ff26c6003a13ec769312c50938b93c359d;p=pandora-kernel.git xen/blkfront: use tagged queuing for barriers When barriers are supported, then use QUEUE_ORDERED_TAG to tell the block subsystem that it doesn't need to do anything else with the barriers. Previously we used ORDERED_DRAIN which caused the block subsystem to drain all pending IO before submitting the barrier, which would be very expensive. Signed-off-by: Jeremy Fitzhardinge --- Reading git-diff-tree failed