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;
>
