Changes in v3:
- Added aio_context_acquire/aio_context_release around blk_drain() in
"virtio-blk: Use blk_drain() to drain IO requests" + updated commit
description
Please update Cc: qemu-stable@ if it necessarily.
Changes in v2:
- Patch "block-backend: Introduce blk_drain() and replace blk_drain_all()"
splitted to two.
- blk_drain() moved to above virtio_blk_data_plane_stop().
Previous thread:
http://lists.gnu.org/archive/html/qemu-devel/2015-06/msg02786.html
During reset the aio_poll() function is called at least amount_of_disks^2 times:
for_each disk
virtio_blk_reset()
bdrv_drain_all()
for_each disk
aio_poll()
For example, startup with 1000 disks takes over 13 minutes.
Patches 1 and 2 removes inner loop by using bdrv_drain() instead
of bdrv_drain_all(). bdrv_drain() works on one disk at time.
Since bdrv_drain_all() is still called in other places, patch 3 optimizes
it for cases, where there are more disks than iothreads.
Thanks.
Alexander Yarygin (2):
block-backend: Introduce blk_drain()
virtio-blk: Use blk_drain() to drain IO requests
block/block-backend.c | 5 +++++
hw/block/virtio-blk.c | 15 ++++++++++-----
include/sysemu/block-backend.h | 1 +
3 files changed, 16 insertions(+), 5 deletions(-)
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1.9.1
