From 684960d46267d6e6443b39ee98b3a95632ba8dc6 Mon Sep 17 00:00:00 2001 From: Stefano Garzarella Date: Tue, 26 Oct 2021 18:23:44 +0200 Subject: 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 Reviewed-by: Kevin Wolf Signed-off-by: Stefano Garzarella Message-Id: <20211026162346.253081-2-sgarzare@redhat.com> Reviewed-by: Stefan Hajnoczi Signed-off-by: Kevin Wolf --- block/file-posix.c | 9 +++++++++ 1 file changed, 9 insertions(+) (limited to 'block') 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; @@ -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); -- cgit v1.2.3-55-g7522