Function _memory_adjust_size_class

vm/ByteCodeTranslator/src/rpmalloc.c:1258–1288

Adjust and optimize the size class properties for the given class

//! Adjust and optimize the size class properties for the given class
static void
_memory_adjust_size_class(size_t iclass) {
	//Calculate how many pages are needed for 255 blocks
	size_t block_size = _memory_size_class[iclass].size;
	size_t page_count = (block_size * 255) / PAGE_SIZE;
	//Cap to 16 pages (64KiB span granularity)
	page_count = (page_count == 0) ? 1 : ((page_count > 16) ? 16 : page_count);
	//Merge page counts to span size class granularity
	page_count = ((page_count + (SPAN_CLASS_GRANULARITY - 1)) / SPAN_CLASS_GRANULARITY) * SPAN_CLASS_GRANULARITY;
	if (page_count > 16)
		page_count = 16;
	size_t block_count = ((page_count * PAGE_SIZE) - SPAN_HEADER_SIZE) / block_size;
	//Store the final configuration
	_memory_size_class[iclass].page_count = (uint16_t)page_count;
	_memory_size_class[iclass].block_count = (uint16_t)block_count;
	_memory_size_class[iclass].class_idx = (uint16_t)iclass;
	
	//Check if previous size classes can be merged
	size_t prevclass = iclass;
	while (prevclass > 0) {
		--prevclass;
		//A class can be merged if number of pages and number of blocks are equal
		if ((_memory_size_class[prevclass].page_count == _memory_size_class[iclass].page_count) &&
		        (_memory_size_class[prevclass].block_count == _memory_size_class[iclass].block_count)) {
			memcpy(_memory_size_class + prevclass, _memory_size_class + iclass, sizeof(_memory_size_class[iclass]));
		}
		else {
			break;
		}
	}
}

#if defined( _WIN32 ) || defined( __WIN32__ ) || defined( _WIN64 )
#  include <windows.h>