From: Fam Zheng <famz@redhat.com>
Date: Wed, 13 May 2015 11:11:13 +0800
Subject: [PATCH] block/mirror: Sleep periodically during bitmap scanning
Before, we only yield after initializing dirty bitmap, where the QMP
command would return. That may take very long, and guest IO will be
blocked.
Add sleep points like the later mirror iterations.
Signed-off-by: Fam Zheng <famz@redhat.com>
Reviewed-by: Wen Congyang <wency@cn.fujitsu.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 1431486673-19280-1-git-send-email-famz@redhat.com
Signed-off-by: Jeff Cody <jcody@redhat.com>
(cherry picked from commit 4c0cbd6fec7db182a6deb52d5a8a8e7b0c5cbe64)
---
block/mirror.c | 13 ++++++++++++-
1 file changed, 12 insertions(+), 1 deletion(-)
diff --git a/block/mirror.c b/block/mirror.c
index b03973c..b56ba66 100644
--- a/block/mirror.c
+++ b/block/mirror.c
@@ -375,11 +375,23 @@ static void coroutine_fn mirror_run(void *opaque)
sectors_per_chunk = s->granularity >> BDRV_SECTOR_BITS;
mirror_free_init(s);
+ last_pause_ns = qemu_clock_get_ns(QEMU_CLOCK_REALTIME);
if (!s->is_none_mode) {
/* First part, loop on the sectors and initialize the dirty bitmap. */
BlockDriverState *base = s->base;
for (sector_num = 0; sector_num < end; ) {
int64_t next = (sector_num | (sectors_per_chunk - 1)) + 1;
+ int64_t now = qemu_clock_get_ns(QEMU_CLOCK_REALTIME);
+
+ if (now - last_pause_ns > SLICE_TIME) {
+ last_pause_ns = now;
+ block_job_sleep_ns(&s->common, QEMU_CLOCK_REALTIME, 0);
+ }
+
+ if (block_job_is_cancelled(&s->common)) {
+ goto immediate_exit;
+ }
+
ret = bdrv_is_allocated_above(bs, base,
sector_num, next - sector_num, &n);
@@ -398,7 +410,6 @@ static void coroutine_fn mirror_run(void *opaque)
}
bdrv_dirty_iter_init(bs, s->dirty_bitmap, &s->hbi);
- last_pause_ns = qemu_clock_get_ns(QEMU_CLOCK_REALTIME);
for (;;) {
uint64_t delay_ns = 0;
int64_t cnt;