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[Qemu-devel] [PULL 09/14] mirror: fix request throttling in drive-mirror
From: |
Jeff Cody |
Subject: |
[Qemu-devel] [PULL 09/14] mirror: fix request throttling in drive-mirror |
Date: |
Tue, 19 Jul 2016 20:20:57 -0400 |
From: "Denis V. Lunev" <address@hidden>
There are 2 deficiencies here:
- mirror_iteration could start several requests inside. Thus we could
simply have more in_flight requests than MAX_IN_FLIGHT.
- keeping this in mind throttling in mirror_run which is checking
s->in_flight == MAX_IN_FLIGHT is wrong.
The patch adds the check and throttling into mirror_iteration and fixes
the check in mirror_run() to be sure.
Signed-off-by: Denis V. Lunev <address@hidden>
Reviewed-by: Max Reitz <address@hidden>
Message-id: address@hidden
CC: Jeff Cody <address@hidden>
CC: Kevin Wolf <address@hidden>
CC: Max Reitz <address@hidden>
Signed-off-by: Jeff Cody <address@hidden>
(cherry picked from commit e648dc95c28fbca12e67be26a1fc4b9a0676c3fe)
---
block/mirror.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/block/mirror.c b/block/mirror.c
index f78186d..836a5d0 100644
--- a/block/mirror.c
+++ b/block/mirror.c
@@ -407,6 +407,11 @@ static uint64_t coroutine_fn
mirror_iteration(MirrorBlockJob *s)
}
}
+ while (s->in_flight >= MAX_IN_FLIGHT) {
+ trace_mirror_yield_in_flight(s, sector_num, s->in_flight);
+ mirror_wait_for_io(s);
+ }
+
mirror_clip_sectors(s, sector_num, &io_sectors);
switch (mirror_method) {
case MIRROR_METHOD_COPY:
@@ -695,7 +700,7 @@ static void coroutine_fn mirror_run(void *opaque)
delta = qemu_clock_get_ns(QEMU_CLOCK_REALTIME) - s->last_pause_ns;
if (delta < SLICE_TIME &&
s->common.iostatus == BLOCK_DEVICE_IO_STATUS_OK) {
- if (s->in_flight == MAX_IN_FLIGHT || s->buf_free_count == 0 ||
+ if (s->in_flight >= MAX_IN_FLIGHT || s->buf_free_count == 0 ||
(cnt == 0 && s->in_flight > 0)) {
trace_mirror_yield(s, s->in_flight, s->buf_free_count, cnt);
mirror_wait_for_io(s);
--
1.9.3
- [Qemu-devel] [PULL 00/14] Block patches, Jeff Cody, 2016/07/19
- [Qemu-devel] [PULL 02/14] mirror: make sectors_in_flight int64_t, Jeff Cody, 2016/07/19
- [Qemu-devel] [PULL 03/14] mirror: create mirror_throttle helper, Jeff Cody, 2016/07/19
- [Qemu-devel] [PULL 04/14] mirror: create mirror_dirty_init helper for mirror_run, Jeff Cody, 2016/07/19
- [Qemu-devel] [PULL 01/14] dirty-bitmap: operate with int64_t amount, Jeff Cody, 2016/07/19
- [Qemu-devel] [PULL 05/14] block: remove extra condition in bdrv_can_write_zeroes_with_unmap, Jeff Cody, 2016/07/19
- [Qemu-devel] [PULL 06/14] mirror: optimize dirty bitmap filling in mirror_run a bit, Jeff Cody, 2016/07/19
- [Qemu-devel] [PULL 08/14] mirror: improve performance of mirroring of empty disk, Jeff Cody, 2016/07/19
- [Qemu-devel] [PULL 07/14] mirror: efficiently zero out target, Jeff Cody, 2016/07/19
- [Qemu-devel] [PULL 09/14] mirror: fix request throttling in drive-mirror,
Jeff Cody <=
- [Qemu-devel] [PULL 10/14] block/gluster: rename [server, volname, image] -> [host, volume, path], Jeff Cody, 2016/07/19
- [Qemu-devel] [PULL 11/14] block/gluster: code cleanup, Jeff Cody, 2016/07/19
- [Qemu-devel] [PULL 12/14] block/gluster: deprecate rdma support, Jeff Cody, 2016/07/19
- [Qemu-devel] [PULL 14/14] block/gluster: add support for multiple gluster servers, Jeff Cody, 2016/07/19
- [Qemu-devel] [PULL 13/14] block/gluster: using new qapi schema, Jeff Cody, 2016/07/19
- Re: [Qemu-devel] [PULL 00/14] Block patches, Peter Maydell, 2016/07/20