Module: GC

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 GC::Profiler.

Defined Under Namespace

Modules: Profiler

Class Method Summary collapse

Instance Method Summary collapse

Class Method Details

.countInteger

The number of times GC occurred.

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

Returns:


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# File 'gc.c', line 3131

static VALUE
gc_count(VALUE self)
{
    return UINT2NUM(rb_objspace.count);
}

.disableBoolean

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

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

Returns:

  • (Boolean)

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# File 'gc.c', line 3280

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

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

.enableBoolean

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

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

Returns:

  • (Boolean)

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# File 'gc.c', line 3258

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

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

.malloc_allocated_sizeInteger

Returns the size of memory allocated by malloc().

Only available if ruby was built with CALC_EXACT_MALLOC_SIZE.

Returns:


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# File 'gc.c', line 3683

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

.malloc_allocationsInteger

Returns the number of malloc() allocations.

Only available if ruby was built with CALC_EXACT_MALLOC_SIZE.

Returns:


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# File 'gc.c', line 3698

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

.startnil .garbage_collectnil .garbage_collectnil

Initiates garbage collection, unless manually disabled.

Overloads:

  • .startnil

    Returns:

    • (nil)
  • .garbage_collectnil

    Returns:

    • (nil)
  • .garbage_collectnil

    Returns:

    • (nil)

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# File 'gc.c', line 3098

VALUE
rb_gc_start(void)
{
    rb_gc();
    return Qnil;
}

.statHash

Returns a Hash containing information about the GC.

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

:count=>0,
:heap_used=>12,
	    :heap_length=>12,
	    :heap_increment=>0,
	    :heap_live_num=>7539,
	    :heap_free_num=>88,
	    :heap_final_num=>0,
	    :total_allocated_object=>7630,
	    :total_freed_object=>88

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.

Returns:


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# File 'gc.c', line 3164

static VALUE
gc_stat(int argc, VALUE *argv, VALUE self)
{
    rb_objspace_t *objspace = &rb_objspace;
    VALUE hash;
    static VALUE sym_count;
    static VALUE sym_heap_used, sym_heap_length, sym_heap_increment;
    static VALUE sym_heap_live_num, sym_heap_free_num, sym_heap_final_num;
    static VALUE sym_total_allocated_object, sym_total_freed_object;
    if (sym_count == 0) {
	sym_count = ID2SYM(rb_intern_const("count"));
	sym_heap_used = ID2SYM(rb_intern_const("heap_used"));
	sym_heap_length = ID2SYM(rb_intern_const("heap_length"));
	sym_heap_increment = ID2SYM(rb_intern_const("heap_increment"));
	sym_heap_live_num = ID2SYM(rb_intern_const("heap_live_num"));
	sym_heap_free_num = ID2SYM(rb_intern_const("heap_free_num"));
	sym_heap_final_num = ID2SYM(rb_intern_const("heap_final_num"));
	sym_total_allocated_object = ID2SYM(rb_intern_const("total_allocated_object"));
	sym_total_freed_object = ID2SYM(rb_intern_const("total_freed_object"));
    }

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

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

    rest_sweep(objspace);

    rb_hash_aset(hash, sym_count, SIZET2NUM(objspace->count));
    /* implementation dependent counters */
    rb_hash_aset(hash, sym_heap_used, SIZET2NUM(objspace->heap.used));
    rb_hash_aset(hash, sym_heap_length, SIZET2NUM(objspace->heap.length));
    rb_hash_aset(hash, sym_heap_increment, SIZET2NUM(objspace->heap.increment));
    rb_hash_aset(hash, sym_heap_live_num, SIZET2NUM(objspace_live_num(objspace)));
    rb_hash_aset(hash, sym_heap_free_num, SIZET2NUM(objspace->heap.free_num));
    rb_hash_aset(hash, sym_heap_final_num, SIZET2NUM(objspace->heap.final_num));
    rb_hash_aset(hash, sym_total_allocated_object, SIZET2NUM(objspace->total_allocated_object_num));
    rb_hash_aset(hash, sym_total_freed_object, SIZET2NUM(objspace->total_freed_object_num));

    return hash;
}

.stressBoolean

Returns current status of GC stress mode.

Returns:

  • (Boolean)

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# File 'gc.c', line 3217

static VALUE
gc_stress_get(VALUE self)
{
    rb_objspace_t *objspace = &rb_objspace;
    return ruby_gc_stress ? Qtrue : Qfalse;
}

.stress=(bool) ⇒ Boolean

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.

Returns:

  • (Boolean)

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# File 'gc.c', line 3236

static VALUE
gc_stress_set(VALUE self, VALUE flag)
{
    rb_objspace_t *objspace = &rb_objspace;
    rb_secure(2);
    ruby_gc_stress = RTEST(flag);
    return flag;
}

Instance Method Details

#startnil #garbage_collectnil #garbage_collectnil

Initiates garbage collection, unless manually disabled.

Overloads:

  • #startnil

    Returns:

    • (nil)
  • #garbage_collectnil

    Returns:

    • (nil)
  • #garbage_collectnil

    Returns:

    • (nil)

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# File 'gc.c', line 3098

VALUE
rb_gc_start(void)
{
    rb_gc();
    return Qnil;
}