When mirroring data blocks, detect if the read data consists entirely of
zeros. If so, use blk_co_pwrite_zeroes() instead of regular write to
improve performance.
Signed-off-by: luzhipeng <luzhip...@cestc.cn>
---
block/mirror.c | 27 +++++++++++++++++++++++++++
1 file changed, 27 insertions(+)
diff --git a/block/mirror.c b/block/mirror.c
index b344182c74..535112f65d 100644
--- a/block/mirror.c
+++ b/block/mirror.c
@@ -269,6 +269,33 @@ static void coroutine_fn mirror_read_complete(MirrorOp
*op, int ret)
return;
}
+ /* Check if the read data is all zeros */
+ bool is_zero = true;
+ for (int i = 0; i < op->qiov.niov; i++) {
+ if (!buffer_is_zero(op->qiov.iov[i].iov_base,
+ op->qiov.iov[i].iov_len)) {
+ is_zero = false;
+ break;
+ }
+ }
+
+ /* Write to target - optimized path for zero blocks */
+ if (is_zero) {
+ /*
+ * Use zero-writing interface which may:
+ * 1. Avoid actual data transfer
+ * 2. Enable storage-level optimizations
+ * 3. Potentially unmap blocks (if supported)
+ */
+ ret = blk_co_pwrite_zeroes(s->target, op->offset,
+ op->qiov.size,
+ BDRV_REQ_MAY_UNMAP);
+ } else {
+ /* Normal data write path */
+ ret = blk_co_pwritev(s->target, op->offset,
+ op->qiov.size, &op->qiov, 0);
+ }
+
ret = blk_co_pwritev(s->target, op->offset, op->qiov.size, &op->qiov, 0);
mirror_write_complete(op, ret);
}
--
2.45.1.windows.1
