Il 15/05/2013 16:34, Stefan Hajnoczi ha scritto:
> + wait_for_overlapping_requests(job, start, end);
> + cow_request_begin(&cow_request, job, start, end);
> +
> + for (; start < end; start++) {
> + if (hbitmap_get(job->bitmap, start)) {
> + DPRINTF("brdv_co_backup_cow skip C%" PRId64 "\n", start);
> + continue; /* already copied */
> + }
> +
> + /* immediately set bitmap (avoid coroutine race) */
> + hbitmap_set(job->bitmap, start, 1);
> +
HBitmap already has code for finding the next set bit, but you're not
using it.
If you reverse the direction of the bitmap, you can use an HBitmapIter here:
>
> + start = 0;
> + end = DIV_ROUND_UP(bdrv_getlength(bs) / BDRV_SECTOR_SIZE,
> + BACKUP_BLOCKS_PER_CLUSTER);
> +
> + job->bitmap = hbitmap_alloc(end, 0);
> +
> + before_write = bdrv_add_before_write_cb(bs, backup_before_write);
> +
> + DPRINTF("backup_run start %s %" PRId64 " %" PRId64 "\n",
> + bdrv_get_device_name(bs), start, end);
> +
> + for (; start < end; start++) {
... instead of iterating through each item manually.
Paolo
> + if (block_job_is_cancelled(&job->common)) {
> + break;
> + }
> +
> + /* we need to yield so that qemu_aio_flush() returns.
> + * (without, VM does not reboot)
> + */
> + if (job->common.speed) {
> + uint64_t delay_ns = ratelimit_calculate_delay(
> + &job->limit, job->sectors_read);
> + job->sectors_read = 0;
> + block_job_sleep_ns(&job->common, rt_clock, delay_ns);
> + } else {
> + block_job_sleep_ns(&job->common, rt_clock, 0);
> + }
> +
> + if (block_job_is_cancelled(&job->common)) {
> + break;
> + }
> +
> + DPRINTF("backup_run loop C%" PRId64 "\n", start);
> +
> + ret = backup_do_cow(bs, start * BACKUP_BLOCKS_PER_CLUSTER, 1);
> + if (ret < 0) {
> + break;
> + }
> +
> + /* Publish progress */
> + job->common.offset += BACKUP_CLUSTER_SIZE;
> + }
