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Re: [Qemu-block] [PATCH v4 4/9] block/io_uring: implements interfaces fo
From: |
Stefan Hajnoczi |
Subject: |
Re: [Qemu-block] [PATCH v4 4/9] block/io_uring: implements interfaces for io_uring |
Date: |
Fri, 7 Jun 2019 15:45:55 +0200 |
User-agent: |
Mutt/1.11.4 (2019-03-13) |
On Mon, Jun 03, 2019 at 06:08:18PM +0530, Aarushi Mehta wrote:
> +static void qemu_luring_process_completions(LuringState *s)
> +{
> + struct io_uring_cqe *cqes;
> + int ret;
> +
> + /*
> + * Request completion callbacks can run the nested event loop.
> + * Schedule ourselves so the nested event loop will "see" remaining
> + * completed requests and process them. Without this, completion
> + * callbacks that wait for other requests using a nested event loop
> + * would hang forever.
> + */
> + qemu_bh_schedule(s->completion_bh);
> +
> + while (io_uring_peek_cqe(&s->ring, &cqes) == 0) {
> + if (!cqes) {
> + break;
> + }
> + LuringAIOCB *luringcb = io_uring_cqe_get_data(cqes);
> + read_barrier();
What is the purpose of this barrier?
> +static void qemu_luring_process_completions_and_submit(LuringState *s)
> +{
> + aio_context_acquire(s->aio_context);
> + qemu_luring_process_completions(s);
> +
> + if (!s->io_q.plugged && !s->io_q.in_queue) {
Submit when there are queued requesting waiting for submission:
s/!s->io_q.in_queue/s->io_q.in_queue > 0/
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- [Qemu-block] [PATCH v4 0/9] Add support for io_uring, Aarushi Mehta, 2019/06/03
- [Qemu-block] [PATCH v4 9/9] block: add trace events for io_uring, Aarushi Mehta, 2019/06/03
- [Qemu-block] [PATCH v4 8/9] block/file-posix.c: extend to use io_uring, Aarushi Mehta, 2019/06/03
- [Qemu-block] [PATCH v4 6/9] util/async: add aio interfaces for io_uring, Aarushi Mehta, 2019/06/03
- [Qemu-block] [PATCH v4 7/9] blockdev: accept io_uring as option, Aarushi Mehta, 2019/06/03
- [Qemu-block] [PATCH v4 5/9] stubs: add stubs for io_uring interface, Aarushi Mehta, 2019/06/03
- [Qemu-block] [PATCH v4 4/9] block/io_uring: implements interfaces for io_uring, Aarushi Mehta, 2019/06/03
- Re: [Qemu-block] [PATCH v4 4/9] block/io_uring: implements interfaces for io_uring,
Stefan Hajnoczi <=
- [Qemu-block] [PATCH v4 3/9] block/block: add BDRV flag for io_uring, Aarushi Mehta, 2019/06/03
- [Qemu-block] [PATCH v4 2/9] qapi/block-core: add option for io_uring, Aarushi Mehta, 2019/06/03
- [Qemu-block] [PATCH v4 1/9] configure: permit use of io_uring, Aarushi Mehta, 2019/06/03
- Re: [Qemu-block] [Qemu-devel] [PATCH v4 0/9] Add support for io_uring, Sergio Lopez, 2019/06/07