module GC

Raises NoMemoryError when allocating an instance of the given classes.

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;
}

The number of times GC occurred.

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

# File ruby_2_7_6/gc.rb, line 99
def self.count
  __builtin_gc_count
end

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

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

# File ruby_2_7_6/gc.rb, line 63
def self.disable
  __builtin_gc_disable
end

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

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

# File ruby_2_7_6/gc.rb, line 51
def self.enable
  __builtin_gc_enable
end

Returns information about the most recent garbage collection.

# File ruby_2_7_6/gc.rb, line 154
def self.latest_gc_info hash_or_key = nil
  __builtin_gc_latest_gc_info hash_or_key
end

Returns the size of memory allocated by malloc().

Only available if ruby was built with CALC_EXACT_MALLOC_SIZE.

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

Returns the number of malloc() allocations.

Only available if ruby was built with CALC_EXACT_MALLOC_SIZE.

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

No longer raises NoMemoryError when allocating an instance of the given classes.

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;
}

Initiates garbage collection, even if 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.

# File ruby_2_7_6/gc.rb, line 33
def self.start full_mark: true, immediate_mark: true, immediate_sweep: true
  __builtin_gc_start_internal full_mark, immediate_mark, immediate_sweep
end

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.

# File ruby_2_7_6/gc.rb, line 144
def self.stat hash_or_key = nil
  __builtin_gc_stat hash_or_key
end

Returns current status of GC stress mode.

# File ruby_2_7_6/gc.rb, line 71
def self.stress
  __builtin_gc_stress_get
end

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

# File ruby_2_7_6/gc.rb, line 89
def self.stress=(flag)
  __builtin_gc_stress_set_m flag
end

Verify compaction reference consistency.

This method is implementation specific. During compaction, objects that were moved are replaced with T_MOVED objects. No object should have a reference to a T_MOVED object after compaction.

This function doubles the heap to ensure room to move all objects, compacts the heap to make sure everything moves, updates all references, then performs a full GC. If any object contains a reference to a T_MOVED object, that object should be pushed on the mark stack, and will make a SEGV.

static VALUE
gc_verify_compaction_references(int argc, VALUE *argv, VALUE mod)
{
    rb_objspace_t *objspace = &rb_objspace;
    int use_toward_empty = FALSE;
    int use_double_pages = FALSE;

    if (dont_gc) return Qnil;

    VALUE opt = Qnil;
    static ID keyword_ids[2];
    VALUE kwvals[2];

    kwvals[1] = Qtrue;

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

    if (!NIL_P(opt)) {
        if (!keyword_ids[0]) {
            keyword_ids[0] = rb_intern("toward");
            keyword_ids[1] = rb_intern("double_heap");
        }

        rb_get_kwargs(opt, keyword_ids, 0, 2, kwvals);
        if (kwvals[0] != Qundef && rb_intern("empty") == rb_sym2id(kwvals[0])) {
            use_toward_empty = TRUE;
        }
        if (kwvals[1] != Qundef && RTEST(kwvals[1])) {
            use_double_pages = TRUE;
        }
    }

    gc_compact(objspace, use_toward_empty, use_double_pages, TRUE);
    return gc_compact_stats(objspace);
}

Verify internal consistency.

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

static VALUE
gc_verify_internal_consistency_m(VALUE dummy)
{
    gc_verify_internal_consistency(&rb_objspace);

    return Qnil;
}