On 27.11.19 19:08, Vladimir Sementsov-Ogievskiy wrote: > Use bdrv_block_status_above to chose effective chunk size and to handle > zeroes effectively. > > This substitutes checking for just being allocated or not, and drops > old code path for it. Assistance by backup job is dropped too, as > caching block-status information is more difficult than just caching > is-allocated information in our dirty bitmap, and backup job is not > good place for this caching anyway. > > Signed-off-by: Vladimir Sementsov-Ogievskiy <vsement...@virtuozzo.com> > --- > block/block-copy.c | 67 +++++++++++++++++++++++++++++++++++++--------- > block/trace-events | 1 + > 2 files changed, 55 insertions(+), 13 deletions(-) > > diff --git a/block/block-copy.c b/block/block-copy.c > index 8602e2cae7..74295d93d5 100644 > --- a/block/block-copy.c > +++ b/block/block-copy.c
[...]
> @@ -336,23 +375,25 @@ int coroutine_fn block_copy(BlockCopyState *s,
> chunk_end = next_zero;
> }
>
> - if (s->skip_unallocated) {
> - ret = block_copy_reset_unallocated(s, start, &status_bytes);
> - if (ret == 0) {
> - trace_block_copy_skip_range(s, start, status_bytes);
> - start += status_bytes;
> - continue;
> - }
> - /* Clamp to known allocated region */
> - chunk_end = MIN(chunk_end, start + status_bytes);
> + ret = block_copy_block_status(s, start, chunk_end - start,
> + &status_bytes);
> + if (s->skip_unallocated && !(ret & BDRV_BLOCK_ALLOCATED)) {
> + bdrv_reset_dirty_bitmap(s->copy_bitmap, start, status_bytes);
> + s->progress_reset_callback(s->progress_opaque);
> + trace_block_copy_skip_range(s, start, status_bytes);
> + start += status_bytes;
> + continue;
> }
>
> + chunk_end = MIN(chunk_end, start + status_bytes);
I’m not sure how much the old “Clamp to known allocated region” actually
helps, but I wouldn’t drop it anyway.
Apart from this nit, the patch looks good to me.
Max
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