9f654b441f
This patch fixes two related issues. One is the race condition in issue #42107.. The other is a crash which happens when the reader is lapped near the end of the buffer.
112 lines
3.9 KiB
C++
112 lines
3.9 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) 2007-2020 Juan Linietsky, Ariel Manzur. */
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/* Copyright (c) 2014-2020 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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#include "core/project_settings.h"
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void CommandQueueMT::lock() {
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mutex.lock();
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}
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void CommandQueueMT::unlock() {
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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_and_epoch >> 1)) {
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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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command_mem_size = GLOBAL_DEF_RST("memory/limits/command_queue/multithreading_queue_size_kb", DEFAULT_COMMAND_MEM_SIZE_KB);
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ProjectSettings::get_singleton()->set_custom_property_info("memory/limits/command_queue/multithreading_queue_size_kb", PropertyInfo(Variant::INT, "memory/limits/command_queue/multithreading_queue_size_kb", PROPERTY_HINT_RANGE, "1,4096,1,or_greater"));
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command_mem_size *= 1024;
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command_mem = (uint8_t *)memalloc(command_mem_size);
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if (p_sync) {
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sync = memnew(Semaphore);
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}
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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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}
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memfree(command_mem);
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}
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