core/command_queue_mt: Customizable size

Partial backport of 9f654b4 to 3.2

core/command_queue_mt.cpp

@@ -31,6 +31,7 @@
 #include "command_queue_mt.h"
 
 #include "core/os/os.h"
+#include "core/project_settings.h"
 
 void CommandQueueMT::lock() {
 
@@ -107,17 +108,22 @@ CommandQueueMT::CommandQueueMT(bool p_sync) {
 	write_ptr = 0;
 	dealloc_ptr = 0;
 	mutex = Mutex::create();
-	command_mem = (uint8_t *)memalloc(COMMAND_MEM_SIZE);
+
+	command_mem_size = GLOBAL_DEF_RST("memory/limits/command_queue/multithreading_queue_size_kb", DEFAULT_COMMAND_MEM_SIZE_KB);
+	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"));
+	command_mem_size *= 1024;
+	command_mem = (uint8_t *)memalloc(command_mem_size);
 
 	for (int i = 0; i < SYNC_SEMAPHORES; i++) {
 
 		sync_sems[i].sem = Semaphore::create();
 		sync_sems[i].in_use = false;
 	}
-	if (p_sync)
+	if (p_sync) {
 		sync = Semaphore::create();
-	else
+	} else {
 		sync = NULL;
+	}
 }
 
 CommandQueueMT::~CommandQueueMT() {

core/command_queue_mt.h

@@ -311,8 +311,7 @@ class CommandQueueMT {
 	/***** BASE *******/
 
 	enum {
-		COMMAND_MEM_SIZE_KB = 256,
-		COMMAND_MEM_SIZE = COMMAND_MEM_SIZE_KB * 1024,
+		DEFAULT_COMMAND_MEM_SIZE_KB = 256,
 		SYNC_SEMAPHORES = 8
 	};
 
@@ -320,6 +319,7 @@ class CommandQueueMT {
 	uint32_t read_ptr;
 	uint32_t write_ptr;
 	uint32_t dealloc_ptr;
+	uint32_t command_mem_size;
 	SyncSemaphore sync_sems[SYNC_SEMAPHORES];
 	Mutex *mutex;
 	Semaphore *sync;
@@ -345,7 +345,7 @@ class CommandQueueMT {
 		} else {
 			// ahead of dealloc_ptr, check that there is room
 
-			if ((COMMAND_MEM_SIZE - write_ptr) < alloc_size + sizeof(uint32_t)) {
+			if ((command_mem_size - write_ptr) < alloc_size + sizeof(uint32_t)) {
 				// no room at the end, wrap down;
 
 				if (dealloc_ptr == 0) { // don't want write_ptr to become dealloc_ptr
@@ -358,7 +358,7 @@ class CommandQueueMT {
 				}
 
 				// if this happens, it's a bug
-				ERR_FAIL_COND_V((COMMAND_MEM_SIZE - write_ptr) < 8, NULL);
+				ERR_FAIL_COND_V((command_mem_size - write_ptr) < 8, NULL);
 				// zero means, wrap to beginning
 
 				uint32_t *p = (uint32_t *)&command_mem[write_ptr];