virtual memory and actor spawner

include/dusk/memory.h

@@ -1,10 +0,0 @@
-#ifndef DUSK_MEMORY_H
-#define DUSK_MEMORY_H
-
-#if TARGET_PC
-#define HEAP_SIZE(original, dusk) (dusk)
-#else
-#define HEAP_SIZE(original, dusk) (original)
-#endif
-
-#endif

include/dusk/vmem.h

@@ -0,0 +1,54 @@
+#pragma once
+#include <stddef.h>
+#ifndef __cplusplus
+#include <stdbool.h>
+#endif
+
+#ifdef __cplusplus
+namespace dusk {
+#endif
+
+// Reserve a contiguous virtual address range without committing physical pages
+void* vmem_reserve(size_t size);
+
+// Commit physical backing for pages in a previously reserved range, ptr and size should be page-aligned
+bool vmem_commit(void* ptr, size_t size);
+
+// Decommit physical pages in a reserved range, releasing RAM without releasing address space
+void vmem_decommit(void* ptr, size_t size);
+
+// Release an entire virtual reservation obtained from vmem_reserve
+void vmem_release(void* ptr, size_t size);
+
+// Returns the OS page size
+size_t vmem_page_size();
+
+// Shared vmem arena
+// All JKR heap vmem reservations are sub-allocated from a single large reservation,
+// keeping the total entry count at 1 regardless of how many heaps exist
+
+// Must be called once before any JKR heap is created
+void vmem_arena_init();
+
+// Allocate a slot of size bytes (page-aligned) from the arena
+void* vmem_arena_alloc(size_t size);
+
+// Return a slot to the arena and decommit its physical pages
+void vmem_arena_free(void* ptr, size_t size);
+
+#ifdef __cplusplus
+} // namespace dusk
+
+// Total virtual address space reserved for the shared JKR heap arena
+inline constexpr size_t JKR_VMEM_ARENA_SIZE = 128ULL * 1024 * 1024 * 1024; // 128 GB
+
+// Virtual address space reserved per JKR heap (one slot in the shared arena)
+inline constexpr size_t JKR_HEAP_VIRTUAL_RESERVE = 64ULL * 1024 * 1024; // 64 MB
+
+// Minimum growth increment when a JKR heap expands into reserved but uncommitted pages
+inline constexpr size_t JKR_HEAP_GROW_CHUNK = 16ULL * 1024 * 1024; // 16 MB
+
+// Maximum number of free slots the arena can track (= total slots in the arena)
+inline constexpr size_t JKR_VMEM_MAX_FREE_SLOTS = JKR_VMEM_ARENA_SIZE / JKR_HEAP_VIRTUAL_RESERVE;
+
+#endif