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IoUringAssmEngn: map StagingBuff w/mmap; reg w/io_uring; add eventFd

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StagingBuffer:
We now allocate memory with mmap(MAP_ANONYMOUS) so that we can be
sure it can be pinned with io_uring_register_buffers(). This
ensures that if DMA is possible, it should be usable.

	IoUringAssemblyEngine:
We now register an eventfd with io_uring so that we can listen
for CQEs with boost::asio.
This commit is contained in:
Hayodea Hekol
2025-11-05 15:34:23 -04:00
parent 0503705a13
commit 94982d50b9
4 changed files with 103 additions and 8 deletions
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stimBuffApis/livoxGen1/ioUringAssemblyEngine.cpp
+47 -4
View File
@@ -1,6 +1,9 @@
#include <boostAsioLinkageFix.h>
#include <cstring>
#include <sys/socket.h>
#include <sys/eventfd.h>
#include <sys/uio.h>
#include <unistd.h>
#include <boost/system/error_code.hpp>
#include <livoxProto1/device.h>
#include <livoxProto1/livoxProto1.h>
@@ -33,7 +36,7 @@ IoUringAssemblyEngine::IoUringAssemblyEngine(PcloudStimulusBuffer& parent_)
: parent(parent_),
frameAssemblyDesc(nullptr), ring{},
isSetup(false),
stallTimer(parent_.device->componentThread->getIoService())
eventfdFd(-1), stallTimer(parent_.device->componentThread->getIoService())
{}
bool IoUringAssemblyEngine::setup()
@@ -61,17 +64,47 @@ bool IoUringAssemblyEngine::setup()
if (udpFd < 0)
{ return false; }
// Declare iovec early to avoid goto crossing initialization
struct iovec iov;
int ret;
/** EXPLANATION:
* Initialize io_uring ring - allocate SQEs and CQEs for one frame assembly
* One SQE per slot (one datagram per slot)
*/
int ret = io_uring_queue_init(
ret = io_uring_queue_init(
static_cast<unsigned int>(frameAssemblyDesc->numSlots), &ring, 0);
if (ret < 0)
{ return false; }
{ goto cleanup; }
// Register staging buffer with io_uring for DMA-apt I/O
iov = parent.stagingBuffer.getIoUringRegisterIoVec();
ret = io_uring_register_buffers(&ring, &iov, 1);
if (ret < 0)
{ goto cleanup_ring; }
// Create eventfd for CQE notifications (used with boost's unified loop)
eventfdFd = eventfd(0, EFD_NONBLOCK);
if (eventfdFd < 0)
{ goto cleanup_buffers; }
// Register eventfd with io_uring
ret = io_uring_register_eventfd(&ring, eventfdFd);
if (ret < 0)
{ goto cleanup_eventfd; }
isSetup = true;
return true;
cleanup_eventfd:
close(eventfdFd);
eventfdFd = -1;
cleanup_buffers:
io_uring_unregister_buffers(&ring);
cleanup_ring:
io_uring_queue_exit(&ring);
cleanup:
return false;
}
void IoUringAssemblyEngine::finalize()
@@ -79,9 +112,16 @@ void IoUringAssemblyEngine::finalize()
// Call stop() to cancel in-flight operations (stop() already cancels the timer)
stop();
// Clean up io_uring ring if it was initialized
if (eventfdFd >= 0)
{
io_uring_unregister_eventfd(&ring);
close(eventfdFd);
eventfdFd = -1;
}
if (isSetup)
{
io_uring_unregister_buffers(&ring);
io_uring_queue_exit(&ring);
isSetup = false;
}
@@ -109,6 +149,9 @@ void IoUringAssemblyEngine::stop()
// 1. Cancel all pending SQEs using io_uring cancellation mechanisms
// 2. Cancel in-flight stall timeout timer via stallTimer.cancel()
// 3. Set appropriate state flags
// Cancel in-flight stall timeout timer
stallTimer.cancel();
}
void IoUringAssemblyEngine::cancelIncompleteAndFillDummies()