It aims to avoid bdev starvation by setting separate
io_context to each bdev_aio io channel and link them
into group channel.
Previous, each ch of aio_bdev on a same spdk_thread shares
same io_context. If one of them submits too many IO to the
io_context, then other channels will be starved.
Moreover, if the first bdev_io gets NOMEM error, then the
following IO of this bdev have no chance to get processed.
The bdev_aio starvation can be reproduced by bdevperf in
v20.04, by:
./bdevperf -q 100 -w randwrite -t 5 -c hdd.conf -o 1048576
(hdd.conf defines 2 aio_bdevs of HDD)
Change-Id: Ic709323f5baeb2f8f7250b75ad872ec4156b5e78
Signed-off-by: Xiaodong Liu <xiaodong.liu@intel.com>
Reviewed-on: https://review.spdk.io/gerrit/c/spdk/spdk/+/3808
Tested-by: SPDK CI Jenkins <sys_sgci@intel.com>
Reviewed-by: Changpeng Liu <changpeng.liu@intel.com>
Reviewed-by: Ziye Yang <ziye.yang@intel.com>
Reviewed-by: Ben Walker <benjamin.walker@intel.com>
Reviewed-by: Jim Harris <james.r.harris@intel.com>
Reviewed-by: Paul Luse <paul.e.luse@intel.com>
Community-CI: Broadcom CI
195fb4e40e