Commit d7ddd0a161 ("linux-aio: limit the batch size using
`aio-max-batch` parameter") added a way to limit the batch size
of Linux AIO backend for the entire AIO context.
The same AIO context can be shared by multiple devices, so
latency-sensitive devices may want to limit the batch size even
more to avoid increasing latency.
For this reason we add the `aio-max-batch` option to the file
backend, which will be used by the next commits to limit the size of
batches including requests generated by this device.
Suggested-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
---
Notes:
v2:
- @aio-max-batch documentation rewrite [Stefan, Kevin]
qapi/block-core.json | 7 +++++++
block/file-posix.c | 9 +++++++++
2 files changed, 16 insertions(+)
diff --git a/qapi/block-core.json b/qapi/block-core.json
index 6d3217abb6..fef76b0ea2 100644
--- a/qapi/block-core.json
+++ b/qapi/block-core.json
@@ -2896,6 +2896,12 @@
# for this device (default: none, forward the commands via SG_IO;
# since 2.11)
# @aio: AIO backend (default: threads) (since: 2.8)
+# @aio-max-batch: maximum number of requests to batch together into a single
+# submission in the AIO backend. The smallest value between
+# this and the aio-max-batch value of the IOThread object is
+# chosen.
+# 0 means that the AIO backend will handle it automatically.
+# (default: 0, since 6.2)