Align up alloc size (#18)

Author: qinsoon

src/julia.h

@@ -2414,6 +2414,14 @@ STATIC_INLINE void mmtk_gc_wb(const void *parent, const void *ptr) JL_NOTSAFEPOI
 {
     mmtk_gc_wb_fast(parent, ptr);
 }
+
+#define MMTK_MIN_ALIGNMENT 4
+// MMTk assumes allocation size is aligned to min alignment.
+STATIC_INLINE size_t mmtk_align_alloc_sz(size_t sz) JL_NOTSAFEPOINT
+{
+    return (sz + MMTK_MIN_ALIGNMENT - 1) & ~(MMTK_MIN_ALIGNMENT - 1);
+}
+
 #endif
 
 #ifdef __cplusplus

src/mmtk-gc.c

@@ -546,7 +546,8 @@ JL_DLLEXPORT void jl_gc_wb2_slow(const void *parent, const void* ptr) JL_NOTSAFE
 void *jl_gc_perm_alloc_nolock(size_t sz, int zero, unsigned align, unsigned offset)
 {
     jl_ptls_t ptls = jl_current_task->ptls;
-    void* addr = mmtk_alloc(&ptls->mmtk_mutator, sz, align, offset, 1);
+    size_t allocsz = mmtk_align_alloc_sz(sz);
+    void* addr = mmtk_alloc(&ptls->mmtk_mutator, allocsz, align, offset, 1);
     return addr;
 }