From: normalperson@...
Date: 2014-08-03T22:58:33+00:00
Subject: [ruby-core:64179] [ruby-trunk - Feature #9894] [RFC] README.EXT: document rb_gc_register_mark_object

Issue #9894 has been updated by Eric Wong.


 I tried making rb_gc_register_address work transparently but wasn't able
 to measure any difference with unicorn.  unicorn uses a few global
 const strings for common HTTP headers, but maybe not enough to matter
 for this patch.
 
 This patch is probably pointless, but in case somebody else wants to try
 and show it makes a difference, it is here:
 
 --- a/gc.c
 +++ b/gc.c
 @@ -5154,13 +5154,15 @@ rb_gc_register_mark_object(VALUE obj)
  void
  rb_gc_register_address(VALUE *addr)
  {
 -    rb_objspace_t *objspace = &rb_objspace;
 -    struct gc_list *tmp;
 -
 -    tmp = ALLOC(struct gc_list);
 -    tmp->next = global_list;
 -    tmp->varptr = addr;
 -    global_list = tmp;
 +    if (OBJ_FROZEN(*addr)) {
 +	rb_gc_register_mark_object(*addr);
 +    } else {
 +	rb_objspace_t *objspace = &rb_objspace;
 +	struct gc_list *tmp = ALLOC(struct gc_list);
 +	tmp->next = global_list;
 +	tmp->varptr = addr;
 +	global_list = tmp;
 +    }
  }
  
  void

----------------------------------------
Feature #9894: [RFC] README.EXT: document rb_gc_register_mark_object
https://bugs.ruby-lang.org/issues/9894#change-48184

* Author: Eric Wong
* Status: Closed
* Priority: Normal
* Assignee: 
* Category: 
* Target version: 
----------------------------------------
 Any comment on officially supporting this as part of the C API?
 
 diff --git a/README.EXT b/README.EXT
 index d66d6c5..dded850 100644
 --- a/README.EXT
 +++ b/README.EXT
 @@ -1176,6 +1176,12 @@ void rb_global_variable(VALUE *var)
  
    Tells GC to protect these variables.
  
 +void rb_gc_register_mark_object(VALUE val)
 +
 +  Tells GC to protect the object referenced by val.  This requires less
 +  memory to track than rb_global_variable, but may only be used if the C
 +  variable never changes.
 +
  == Constant Definition
  
  void rb_define_const(VALUE klass, const char *name, VALUE val) ::
 -- 
 Eric Wong



-- 
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