[PATCH] remove mimmalloc/mimfree for vm and main thread

[PATCH] remove mimmalloc/mimfree for vm and main thread

[Eric Wong]

MVM probably will not happen.  Even if MVM proceeds, any process (at
least on *nix) will always have at least one VM and one thread.
Instead of hitting the heap so early on and having a specialized
malloc, use the text area of a process to simplify code and
potentially allow sighandler to work without wasting syscalls
during shutdown.
---
 gc.c       | 29 -----------------------------
 internal.h |  2 --
 vm.c       | 15 +++++----------
 3 files changed, 5 insertions(+), 41 deletions(-)

diff --git a/gc.c b/gc.c
index 2bb5f7a..97228c9 100644
--- a/gc.c
+++ b/gc.c
@@ -7723,35 +7723,6 @@ ruby_xfree(void *x)
     ruby_sized_xfree(x, 0);
 }
 
-/* Mimic ruby_xmalloc, but need not rb_objspace.
- * should return pointer suitable for ruby_xfree
- */
-void *
-ruby_mimmalloc(size_t size)
-{
-    void *mem;
-#if CALC_EXACT_MALLOC_SIZE
-    size += sizeof(size_t);
-#endif
-    mem = malloc(size);
-#if CALC_EXACT_MALLOC_SIZE
-    /* set 0 for consistency of allocated_size/allocations */
-    ((size_t *)mem)[0] = 0;
-    mem = (size_t *)mem + 1;
-#endif
-    return mem;
-}
-
-void
-ruby_mimfree(void *ptr)
-{
-    size_t *mem = (size_t *)ptr;
-#if CALC_EXACT_MALLOC_SIZE
-    mem = mem - 1;
-#endif
-    free(mem);
-}
-
 #if MALLOC_ALLOCATED_SIZE
 /*
  *  call-seq:
diff --git a/internal.h b/internal.h
index c91d8ca..185a09f 100644
--- a/internal.h
+++ b/internal.h
@@ -802,8 +802,6 @@ NORETURN(void rb_syserr_fail_path_in(const char *func_name, int err, VALUE path)
 extern VALUE *ruby_initial_gc_stress_ptr;
 extern int ruby_disable_gc;
 void Init_heap(void);
-void *ruby_mimmalloc(size_t size);
-void ruby_mimfree(void *ptr);
 void rb_objspace_set_event_hook(const rb_event_flag_t event);
 #if USE_RGENGC
 void rb_gc_writebarrier_remember(VALUE obj);
diff --git a/vm.c b/vm.c
index bbd5320..986f547 100644
--- a/vm.c
+++ b/vm.c
@@ -1878,11 +1878,11 @@ ruby_vm_destruct(rb_vm_t *vm)
 #if defined(ENABLE_VM_OBJSPACE) && ENABLE_VM_OBJSPACE
 	struct rb_objspace *objspace = vm->objspace;
 #endif
-	vm->main_thread = 0;
 	if (th) {
 	    rb_fiber_reset_root_local_storage(th->self);
 	    thread_free(th);
 	}
+	vm->main_thread = 0;
 	rb_vm_living_threads_init(vm);
 	ruby_vm_run_at_exit_hooks(vm);
 	rb_vm_gvl_destroy(vm);
@@ -1891,8 +1891,6 @@ ruby_vm_destruct(rb_vm_t *vm)
 	    rb_objspace_free(objspace);
 	}
 #endif
-	/* after freeing objspace, you *can't* use ruby_xfree() */
-	ruby_mimfree(vm);
 	ruby_current_vm = 0;
     }
     RUBY_FREE_LEAVE("vm");
@@ -2810,14 +2808,11 @@ struct rb_objspace *rb_objspace_alloc(void);
 void
 Init_BareVM(void)
 {
+    static rb_vm_t ruby_main_vm;
+    static rb_thread_t ruby_main_thread;
     /* VM bootstrap: phase 1 */
-    rb_vm_t * vm = ruby_mimmalloc(sizeof(*vm));
-    rb_thread_t * th = ruby_mimmalloc(sizeof(*th));
-    if (!vm || !th) {
-	fprintf(stderr, "[FATAL] failed to allocate memory\n");
-	exit(EXIT_FAILURE);
-    }
-    MEMZERO(th, rb_thread_t, 1);
+    rb_vm_t *vm = &ruby_main_vm;
+    rb_thread_t *th = &ruby_main_thread;
     rb_thread_set_current_raw(th);
 
     vm_init2(vm);
-- 
EW