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Module: GC

Relationships & Source Files
Namespace Children
Modules:
Profiler
Defined in: gc.c

Overview

The GC module provides an interface to Ruby's mark and sweep garbage collection mechanism.

Some of the underlying methods are also available via the ::ObjectSpace module.

You may obtain information about the operation of the GC through Profiler.

Constant Summary

Class Attribute Summary

Class Method Summary

Instance Method Summary

Class Attribute Details

.stress ⇒ Boolean (rw)

Returns current status of GC stress mode.

[ GitHub ] 

  


# File 'gc.c', line 7316



static VALUE
gc_stress_get(VALUE self)
{
    rb_objspace_t *objspace = &rb_objspace;
    return ruby_gc_stress_mode;
}


  








  

    .stress=(flag)  ⇒ flag  (rw)  



  

    

Updates the GC stress mode.



When stress mode is enabled, the GC is invoked at every GC opportunity: all memory and object allocations.



Enabling stress mode will degrade performance, it is only for debugging.



flag can be true, false, or an integer bit-ORed following flags.



0x01:: no major GC
0x02:: no immediate sweep
0x04:: full mark after malloc/calloc/realloc


  



  [ GitHub ]


  

  


# File 'gc.c', line 7347



static VALUE
gc_stress_set_m(VALUE self, VALUE flag)
{
    rb_objspace_t *objspace = &rb_objspace;
    gc_stress_set(objspace, flag);
    return flag;
}


  







Class Method Details



  

    .add_stress_to_class(*args)  
  

  [ GitHub ]


  

  


# File 'gc.c', line 9517



static VALUE
rb_gcdebug_add_stress_to_class(int argc, VALUE *argv, VALUE self)
{
    rb_objspace_t *objspace = &rb_objspace;

    if (!stress_to_class) {
	stress_to_class = rb_ary_tmp_new(argc);
    }
    rb_ary_cat(stress_to_class, argv, argc);
    return self;
}


  








  

    .count  ⇒ Integer   



  

    

The number of times GC occurred.



It returns the number of times GC occurred since the process started.


  



  [ GitHub ]


  

  


# File 'gc.c', line 6783



static VALUE
gc_count(VALUE self)
{
    return SIZET2NUM(rb_gc_count());
}


  








  

    .disable  ⇒ Boolean   



  

    

Disables garbage collection, returning true if garbage collection was already disabled.



GC.disable   #=> false
GC.disable   #=> true


  



  [ GitHub ]


  

  


# File 'gc.c', line 7390



VALUE
rb_gc_disable(void)
{
    rb_objspace_t *objspace = &rb_objspace;
    int old = dont_gc;

    gc_rest(objspace);

    dont_gc = TRUE;
    return old ? Qtrue : Qfalse;
}


  








  

    .enable  ⇒ Boolean   



  

    

Enables garbage collection, returning true if garbage collection was previously disabled.



GC.disable   #=> false
GC.enable    #=> true
GC.enable    #=> false


  



  [ GitHub ]


  

  


# File 'gc.c', line 7368



VALUE
rb_gc_enable(void)
{
    rb_objspace_t *objspace = &rb_objspace;
    int old = dont_gc;

    dont_gc = FALSE;
    return old ? Qtrue : Qfalse;
}


  








  

    

      .latest_gc_info  ⇒ GC 
      .latest_gc_info(hash)  ⇒ Hash 
      .latest_gc_info(:major_by)  ⇒ :malloc 
    

  



  

    

Returns information about the most recent garbage collection.


  





  


  [ GitHub ]


  

  


# File 'gc.c', line 6898



static VALUE
gc_latest_gc_info(int argc, VALUE *argv, VALUE self)
{
    rb_objspace_t *objspace = &rb_objspace;
    VALUE arg = Qnil;

    if (rb_scan_args(argc, argv, "01", &arg) == 1) {
	if (!SYMBOL_P(arg) && !RB_TYPE_P(arg, T_HASH)) {
	    rb_raise(rb_eTypeError, "non-hash or symbol given");
	}
    }

    if (arg == Qnil) {
	arg = rb_hash_new();
    }

    return gc_info_decode(objspace, arg, 0);
}


  








  

    .malloc_allocated_size  ⇒ Integer   



  

    

Returns the size of memory allocated by malloc().



Only available if ruby was built with CALC_EXACT_MALLOC_SIZE.


  



  [ GitHub ]


  

  


# File 'gc.c', line 8168



static VALUE
gc_malloc_allocated_size(VALUE self)
{
    return UINT2NUM(rb_objspace.malloc_params.allocated_size);
}


  








  

    .malloc_allocations  ⇒ Integer   



  

    

Returns the number of malloc() allocations.



Only available if ruby was built with CALC_EXACT_MALLOC_SIZE.


  



  [ GitHub ]


  

  


# File 'gc.c', line 8183



static VALUE
gc_malloc_allocations(VALUE self)
{
    return UINT2NUM(rb_objspace.malloc_params.allocations);
}


  








  

    .remove_stress_to_class(*args)  
  

  [ GitHub ]


  

  


# File 'gc.c', line 9529



static VALUE
rb_gcdebug_remove_stress_to_class(int argc, VALUE *argv, VALUE self)
{
    rb_objspace_t *objspace = &rb_objspace;
    int i;

    if (stress_to_class) {
	for (i = 0; i < argc; ++i) {
	    rb_ary_delete_same(stress_to_class, argv[i]);
	}
	if (RARRAY_LEN(stress_to_class) == 0) {
	    stress_to_class = 0;
	}
    }
    return Qnil;
}


  








  

    

      #start  ⇒ nil 
      ObjectSpace.garbage_collect  ⇒ nil 
      #include(GC; garbage_collect)  ⇒ nil 
      #start(full_mark: true, immediate_sweep: true)  ⇒ nil 
      ObjectSpace.garbage_collect(full_mark: true, immediate_sweep: true)  ⇒ nil 
      #include(GC; garbage_collect(full_mark: true, immediate_sweep: true)  ⇒ nil 
    

    Also known as: #garbage_collect
  



  

    

Initiates garbage collection, unless manually disabled.



This method is defined with keyword arguments that default to true:



def GC.start(full_mark: true, immediate_sweep: true); end



Use full_mark: false to perform a minor GC. Use immediate_sweep: false to defer sweeping (use lazy sweep).



Note: These keyword arguments are implementation and version dependent. They are not guaranteed to be future-compatible, and may be ignored if the underlying implementation does not support them.


  





  


  [ GitHub ]


  

  


# File 'gc.c', line 6696



static VALUE
gc_start_internal(int argc, VALUE *argv, VALUE self)
{
    rb_objspace_t *objspace = &rb_objspace;
    int full_mark = TRUE, immediate_mark = TRUE, immediate_sweep = TRUE;
    VALUE opt = Qnil;
    static ID keyword_ids[3];

    rb_scan_args(argc, argv, "0:", &opt);

    if (!NIL_P(opt)) {
	VALUE kwvals[3];

	if (!keyword_ids[0]) {
	    keyword_ids[0] = rb_intern("full_mark");
	    keyword_ids[1] = rb_intern("immediate_mark");
	    keyword_ids[2] = rb_intern("immediate_sweep");
	}

	rb_get_kwargs(opt, keyword_ids, 0, 3, kwvals);

	if (kwvals[0] != Qundef) full_mark = RTEST(kwvals[0]);
	if (kwvals[1] != Qundef) immediate_mark = RTEST(kwvals[1]);
	if (kwvals[2] != Qundef) immediate_sweep = RTEST(kwvals[2]);
    }

    garbage_collect(objspace, full_mark, immediate_mark, immediate_sweep, GPR_FLAG_METHOD);
    gc_finalize_deferred(objspace);

    return Qnil;
}


  








  

    

      .stat  ⇒ Hash 
      .stat(hash)  ⇒ Hash 
      .stat(:key)  ⇒ Numeric 
    

  



  

    

Returns a ::Hash containing information about the GC.



The hash includes information about internal statistics about GC such as:



{
    :count=>0,
    :heap_allocated_pages=>24,
    :heap_sorted_length=>24,
    :heap_allocatable_pages=>0,
    :heap_available_slots=>9783,
    :heap_live_slots=>7713,
    :heap_free_slots=>2070,
    :heap_final_slots=>0,
    :heap_marked_slots=>0,
    :heap_eden_pages=>24,
    :heap_tomb_pages=>0,
    :total_allocated_pages=>24,
    :total_freed_pages=>0,
    :total_allocated_objects=>7796,
    :total_freed_objects=>83,
    :malloc_increase_bytes=>2389312,
    :malloc_increase_bytes_limit=>16777216,
    :minor_gc_count=>0,
    :major_gc_count=>0,
    :remembered_wb_unprotected_objects=>0,
    :remembered_wb_unprotected_objects_limit=>0,
    :old_objects=>0,
    :old_objects_limit=>0,
    :oldmalloc_increase_bytes=>2389760,
    :oldmalloc_increase_bytes_limit=>16777216
}



The contents of the hash are implementation specific and may be changed in the future.



This method is only expected to work on C Ruby.


  





  


  [ GitHub ]


  

  


# File 'gc.c', line 7274



static VALUE
gc_stat(int argc, VALUE *argv, VALUE self)
{
    VALUE arg = Qnil;

    if (rb_scan_args(argc, argv, "01", &arg) == 1) {
	if (SYMBOL_P(arg)) {
	    size_t value = gc_stat_internal(arg);
	    return SIZET2NUM(value);
	}
	else if (!RB_TYPE_P(arg, T_HASH)) {
	    rb_raise(rb_eTypeError, "non-hash or symbol given");
	}
    }

    if (arg == Qnil) {
        arg = rb_hash_new();
    }
    gc_stat_internal(arg);
    return arg;
}


  








  

    .verify_internal_consistency  ⇒ nil   



  

    

Verify internal consistency.



This method is implementation specific. Now this method checks generational consistency if RGenGC is supported.


  



  [ GitHub ]


  

  


# File 'gc.c', line 5315



static VALUE
gc_verify_internal_consistency(VALUE dummy)
{
    rb_objspace_t *objspace = &rb_objspace;
    struct verify_internal_consistency_struct data = {0};
    struct each_obj_args eo_args;

    data.objspace = objspace;
    gc_report(5, objspace, "gc_verify_internal_consistency: start\n");

    /* check relations */

    eo_args.callback = verify_internal_consistency_i;
    eo_args.data = (void *)&data;
    objspace_each_objects((VALUE)&eo_args);

    if (data.err_count != 0) {
#if RGENGC_CHECK_MODE >= 5
	objspace->rgengc.error_count = data.err_count;
	gc_marks_check(objspace, NULL, NULL);
	allrefs_dump(objspace);
#endif
	rb_bug("gc_verify_internal_consistency: found internal inconsistency.");
    }

    /* check heap_page status */
    gc_verify_heap_pages(objspace);

    /* check counters */

    if (!is_lazy_sweeping(heap_eden) && !finalizing) {
	if (objspace_live_slots(objspace) != data.live_object_count) {
	    fprintf(stderr, "heap_pages_final_slots: %d, objspace->profile.total_freed_objects: %d\n",
		    (int)heap_pages_final_slots, (int)objspace->profile.total_freed_objects);
	    rb_bug("inconsistent live slot number: expect %"PRIuSIZE", but %"PRIuSIZE".", objspace_live_slots(objspace), data.live_object_count);
	}
    }

#if USE_RGENGC
    if (!is_marking(objspace)) {
	if (objspace->rgengc.old_objects != data.old_object_count) {
	    rb_bug("inconsistent old slot number: expect %"PRIuSIZE", but %"PRIuSIZE".", objspace->rgengc.old_objects, data.old_object_count);
	}
	if (objspace->rgengc.uncollectible_wb_unprotected_objects != data.remembered_shady_count) {
	    rb_bug("inconsistent old slot number: expect %"PRIuSIZE", but %"PRIuSIZE".", objspace->rgengc.uncollectible_wb_unprotected_objects, data.remembered_shady_count);
	}
    }
#endif

    if (!finalizing) {
	size_t list_count = 0;

	{
	    VALUE z = heap_pages_deferred_final;
	    while (z) {
		list_count++;
		z = RZOMBIE(z)->next;
	    }
	}

	if (heap_pages_final_slots != data.zombie_object_count ||
	    heap_pages_final_slots != list_count) {

	    rb_bug("inconsistent finalizing object count:\n"
		   "  expect %"PRIuSIZE"\n"
		   "  but    %"PRIuSIZE" zombies\n"
		   "  heap_pages_deferred_final list has %"PRIuSIZE" items.",
		   heap_pages_final_slots,
		   data.zombie_object_count,
		   list_count);
	}
    }

    gc_report(5, objspace, "gc_verify_internal_consistency: OK\n");

    return Qnil;
}


  







Instance Method Details



  

    

      #start  ⇒ nil 
      ObjectSpace.garbage_collect  ⇒ nil 
      #include(GC; garbage_collect)  ⇒ nil 
      #start(full_mark: true, immediate_sweep: true)  ⇒ nil 
      ObjectSpace.garbage_collect(full_mark: true, immediate_sweep: true)  ⇒ nil 
      #include(GC; garbage_collect(full_mark: true, immediate_sweep: true)  ⇒ nil 
    

  



  

    

Alias for .start.