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[PATCH v2 1/3] file-posix: add `aio-max-batch` option
From: |
Stefano Garzarella |
Subject: |
[PATCH v2 1/3] file-posix: add `aio-max-batch` option |
Date: |
Tue, 26 Oct 2021 18:23:44 +0200 |
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)
# @locking: whether to enable file locking. If set to 'auto', only enable
# when Open File Descriptor (OFD) locking API is available
# (default: auto, since 2.10)
@@ -2924,6 +2930,7 @@
'*pr-manager': 'str',
'*locking': 'OnOffAuto',
'*aio': 'BlockdevAioOptions',
+ '*aio-max-batch': 'int',
'*drop-cache': {'type': 'bool',
'if': 'CONFIG_LINUX'},
'*x-check-cache-dropped': 'bool' },
diff --git a/block/file-posix.c b/block/file-posix.c
index 53be0bdc1b..d655fd0c45 100644
--- a/block/file-posix.c
+++ b/block/file-posix.c
@@ -150,6 +150,8 @@ typedef struct BDRVRawState {
uint64_t locked_perm;
uint64_t locked_shared_perm;
+ uint64_t aio_max_batch;
+
int perm_change_fd;
int perm_change_flags;
BDRVReopenState *reopen_state;
@@ -530,6 +532,11 @@ static QemuOptsList raw_runtime_opts = {
.type = QEMU_OPT_STRING,
.help = "host AIO implementation (threads, native, io_uring)",
},
+ {
+ .name = "aio-max-batch",
+ .type = QEMU_OPT_NUMBER,
+ .help = "AIO max batch size (0 = auto handled by AIO backend,
default: 0)",
+ },
{
.name = "locking",
.type = QEMU_OPT_STRING,
@@ -609,6 +616,8 @@ static int raw_open_common(BlockDriverState *bs, QDict
*options,
s->use_linux_io_uring = (aio == BLOCKDEV_AIO_OPTIONS_IO_URING);
#endif
+ s->aio_max_batch = qemu_opt_get_number(opts, "aio-max-batch", 0);
+
locking = qapi_enum_parse(&OnOffAuto_lookup,
qemu_opt_get(opts, "locking"),
ON_OFF_AUTO_AUTO, &local_err);
--
2.31.1
[PATCH v2 3/3] linux-aio: add `dev_max_batch` parameter to laio_io_unplug(), Stefano Garzarella, 2021/10/26
[PATCH v2 2/3] linux-aio: add `dev_max_batch` parameter to laio_co_submit(), Stefano Garzarella, 2021/10/26