static struct scatterlist *alloc_sgtable(int size)
{
	int alloc_size, nents, i;
	struct page *new_page;
	struct scatterlist *iter;
	struct scatterlist *table;

	nents = DIV_ROUND_UP(size, PAGE_SIZE);
	table = kcalloc(nents, sizeof(*table), GFP_KERNEL);
	if (!table)
		return NULL;
	sg_init_table(table, nents);
	iter = table;
	for_each_sg(table, iter, sg_nents(table), i) {
		new_page = alloc_page(GFP_KERNEL);
		if (!new_page) {
			/* release all previous allocated pages in the table */
			iter = table;
			for_each_sg(table, iter, sg_nents(table), i) {
				new_page = sg_page(iter);
				if (new_page)
					__free_page(new_page);
			}
			kfree(table);
			return NULL;
		}
		alloc_size = min_t(int, size, PAGE_SIZE);
		size -= PAGE_SIZE;
		sg_set_page(iter, new_page, alloc_size, 0);
	}
	return table;
}
The software does not sufficiently track and release allocated memory after it has been used, which slowly consumes remaining memory.