Shiqing Gao fed8ce513c dm: block_if: add the io_uring support ...

io_uring is a high-performance asynchronous I/O framework, primarily designed
to improve the efficiency of input and output (I/O) operations in user-space
applications.
This patch enables io_uring in block_if module. It utilizes the interfaces
provided by the user-space library `liburing` to interact with io_uring
in kernel-space.

To build the acrn-dm with io_uring support, `liburing-dev` package needs to be
installed. For example, it can be installed like below in Ubuntu 22.04.
        sudo apt install liburing-dev

In order to support both the thread pool mechanism and the io_uring mechanism,
an acrn-dm option `aio` is introduced. By default, thread pool mechanism is
selected.
- Example to use io_uring:
  `add_virtual_device    9 virtio-blk iothread,mq=2,/dev/nvme1n1,writeback,aio=io_uring`
- Example to use thread pool:
  `add_virtual_device    9 virtio-blk iothread,mq=2,/dev/nvme1n1,writeback,aio=threads`
- Example to use thread pool (by default):
  `add_virtual_device    9 virtio-blk iothread,mq=2,/dev/nvme1n1,writeback`

v2 -> v3:
 * Update iothread_handler
    - Use the unified eventfd interfaces to read the counter value of the
      ioeventfd.
    - Remove the while loop to read the ioeventfd. It is not necessary
      because one read would reset the counter value to 0.
 * Update iou_submit_sqe to return an error code
   The caller of iou_submit_sqe shall check the return value.
   If there is NO available submission queue entry in the submission queue,
   need to break the while loop. Request can only be submitted when SQE is
   available.

v1 -> v2:
 * move the logic of reading out ioeventfd from iothread.c to virtio.c, because
   it is specific to the virtqueue handling.

Tracked-On: #8612

Signed-off-by: Shiqing Gao <shiqing.gao@intel.com>
Acked-by: Wang, Yu1 <yu1.wang@intel.com>

2024-06-05 15:23:33 +08:00

6.8 KiB

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