vhost I/O only need to be split on 2MB boundaries if
there is a break in the VM's memtable at that 2MB
boundary.
This should drastically reduce (if not eliminate)
the intermittent test pool failures seen recently.
virtio limits number of segments to 128, but this
2MB splitting could introduce additional segment
breaks which we do not allocate IOVs for. In almost
all cases, there are no memtable breaks except at
low 2MB, so most of the extra segment breaks we are
adding are unnecessary.
Signed-off-by: Jim Harris <james.r.harris@intel.com>
Change-Id: I12d85c289ad80c7bb65e3d2030a2405092b19deb
Reviewed-on: https://review.gerrithub.io/396058
Reviewed-by: Daniel Verkamp <daniel.verkamp@intel.com>
Tested-by: SPDK Automated Test System <sys_sgsw@intel.com>
Reviewed-by: Changpeng Liu <changpeng.liu@intel.com>
Reviewed-by: Dariusz Stojaczyk <dariuszx.stojaczyk@intel.com>
f570aa654a