diff options
| author | Stefano Garzarella <sgarzare@redhat.com> | 2021-10-26 18:23:44 +0200 |
|---|---|---|
| committer | Kevin Wolf <kwolf@redhat.com> | 2021-11-02 13:03:30 +0100 |
| commit | 684960d46267d6e6443b39ee98b3a95632ba8dc6 (patch) | |
| tree | d265c1c5e59a570e2a7bab20225b2a2d8014e47c | |
| parent | 304332039014679b809f606e2f227ee0fc43a451 (diff) | |
file-posix: add `aio-max-batch` option
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>
Message-Id: <20211026162346.253081-2-sgarzare@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
| -rw-r--r-- | block/file-posix.c | 9 | ||||
| -rw-r--r-- | qapi/block-core.json | 7 |
2 files changed, 16 insertions, 0 deletions
diff --git a/block/file-posix.c b/block/file-posix.c index 6def2a4cba..7a289a9481 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; @@ -531,6 +533,11 @@ static QemuOptsList raw_runtime_opts = { .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, .help = "file locking mode (on/off/auto, default: auto)", @@ -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); diff --git a/qapi/block-core.json b/qapi/block-core.json index ce2c1352cb..ea36e0038c 100644 --- a/qapi/block-core.json +++ b/qapi/block-core.json @@ -2939,6 +2939,12 @@ # 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) @@ -2968,6 +2974,7 @@ '*pr-manager': 'str', '*locking': 'OnOffAuto', '*aio': 'BlockdevAioOptions', + '*aio-max-batch': 'int', '*drop-cache': {'type': 'bool', 'if': 'CONFIG_LINUX'}, '*x-check-cache-dropped': { 'type': 'bool', |