On 13/05/2015 05:11, Fam Zheng wrote: > 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.
You were also planning to let bdrv_co_is_allocated/get_block_status return a larger p_num than nb_sectors---which maybe could make nb_sectors obsolete completely, I don't know. But this is already an improvement. Reviewed-by: Paolo Bonzini <pbonz...@redhat.com> Thanks, Paolo > > Signed-off-by: Fam Zheng <f...@redhat.com> > --- > block/mirror.c | 13 ++++++++++++- > 1 file changed, 12 insertions(+), 1 deletion(-) > > diff --git a/block/mirror.c b/block/mirror.c > index 1a1d997..baed225 100644 > --- a/block/mirror.c > +++ b/block/mirror.c > @@ -467,11 +467,23 @@ 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); > > @@ -490,7 +502,6 @@ static void coroutine_fn mirror_run(void *opaque) > } > > bdrv_dirty_iter_init(s->dirty_bitmap, &s->hbi); > - last_pause_ns = qemu_clock_get_ns(QEMU_CLOCK_REALTIME); > for (;;) { > uint64_t delay_ns = 0; > int64_t cnt; >