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 <address@hidden>
---
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.