24e7a54cd0
The allocations of commands in CommandQueueMT weren't aligned. This commit aligns all accesses on 64bit boundaries regardless of target platform. This ensures that all types are aligned. Lock-wise the semaphores were maked as usable when the command had ran but not when the synchronous stub had finished with it. This lead to a race condition where sometimes the semaphore got reused before it was waited on. We now mark the semaphore as free only once we're done waiting on it.
133 lines
3.8 KiB
C++
133 lines
3.8 KiB
C++
/*************************************************************************/
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/* command_queue_mt.cpp */
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/*************************************************************************/
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/* This file is part of: */
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/* GODOT ENGINE */
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/* https://godotengine.org */
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/*************************************************************************/
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/* Copyright (c) 2007-2019 Juan Linietsky, Ariel Manzur. */
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/* Copyright (c) 2014-2019 Godot Engine contributors (cf. AUTHORS.md) */
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/* */
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/* Permission is hereby granted, free of charge, to any person obtaining */
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/* a copy of this software and associated documentation files (the */
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/* "Software"), to deal in the Software without restriction, including */
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/* without limitation the rights to use, copy, modify, merge, publish, */
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/* distribute, sublicense, and/or sell copies of the Software, and to */
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/* permit persons to whom the Software is furnished to do so, subject to */
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/* the following conditions: */
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/* */
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/* The above copyright notice and this permission notice shall be */
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/* included in all copies or substantial portions of the Software. */
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/* */
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/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, */
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/* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF */
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/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.*/
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/* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY */
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/* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, */
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/* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE */
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/* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */
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/*************************************************************************/
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#include "command_queue_mt.h"
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#include "core/os/os.h"
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void CommandQueueMT::lock() {
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if (mutex)
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mutex->lock();
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}
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void CommandQueueMT::unlock() {
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if (mutex)
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mutex->unlock();
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}
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void CommandQueueMT::wait_for_flush() {
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// wait one millisecond for a flush to happen
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OS::get_singleton()->delay_usec(1000);
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}
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CommandQueueMT::SyncSemaphore *CommandQueueMT::_alloc_sync_sem() {
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int idx = -1;
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while (true) {
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lock();
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for (int i = 0; i < SYNC_SEMAPHORES; i++) {
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if (!sync_sems[i].in_use) {
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sync_sems[i].in_use = true;
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idx = i;
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break;
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}
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}
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unlock();
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if (idx == -1) {
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wait_for_flush();
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} else {
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break;
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}
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}
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return &sync_sems[idx];
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}
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bool CommandQueueMT::dealloc_one() {
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tryagain:
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if (dealloc_ptr == write_ptr) {
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// The queue is empty
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return false;
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}
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uint32_t size = *(uint32_t *)&command_mem[dealloc_ptr];
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if (size == 0) {
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// End of command buffer wrap down
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dealloc_ptr = 0;
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goto tryagain;
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}
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if (size & 1) {
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// Still used, nothing can be deallocated
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return false;
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}
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dealloc_ptr += (size >> 1) + 8;
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return true;
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}
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CommandQueueMT::CommandQueueMT(bool p_sync) {
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read_ptr = 0;
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write_ptr = 0;
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dealloc_ptr = 0;
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mutex = Mutex::create();
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command_mem = (uint8_t *)memalloc(COMMAND_MEM_SIZE);
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for (int i = 0; i < SYNC_SEMAPHORES; i++) {
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sync_sems[i].sem = Semaphore::create();
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sync_sems[i].in_use = false;
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}
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if (p_sync)
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sync = Semaphore::create();
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else
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sync = NULL;
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}
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CommandQueueMT::~CommandQueueMT() {
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if (sync)
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memdelete(sync);
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memdelete(mutex);
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for (int i = 0; i < SYNC_SEMAPHORES; i++) {
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memdelete(sync_sems[i].sem);
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}
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memfree(command_mem);
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}
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