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;
}

Returns whether or not automatic compaction has been enabled.

# File gc.rb, line 46
def self.auto_compact
  Primitive.gc_get_auto_compact
end

Updates automatic compaction mode.

When enabled, the compactor will execute on every major collection.

Enabling compaction will degrade performance on major collections.

# File gc.rb, line 58
def self.auto_compact=(flag)
  Primitive.gc_set_auto_compact(flag)
end

This function compacts objects together in Ruby's heap. It eliminates unused space (or fragmentation) in the heap by moving objects in to that unused space. This function returns a hash which contains statistics about which objects were moved. See `GC.latest_gc_info` for details about compaction statistics.

This method is implementation specific and not expected to be implemented in any implementation besides MRI.

# File gc.rb, line 212
def self.compact
  Primitive.gc_compact
end

The number of times GC occurred.

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

# File gc.rb, line 120
def self.count
  Primitive.gc_count
end

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

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

# File gc.rb, line 84
def self.disable
  Primitive.gc_disable
end

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

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

# File gc.rb, line 72
def self.enable
  Primitive.gc_enable
end

Returns information about object moved in the most recent GC compaction.

The returned hash has two keys :considered and :moved. The hash for :considered lists the number of objects that were considered for movement by the compactor, and the :moved hash lists the number of objects that were actually moved. Some objects can't be moved (maybe they were pinned) so these numbers can be used to calculate compaction efficiency.

# File gc.rb, line 197
def self.latest_compact_info
  Primitive.gc_compact_stats
end

Returns information about the most recent garbage collection.

If the optional argument, hash, is given, it is overwritten and returned. This is intended to avoid probe effect.

# File gc.rb, line 183
def self.latest_gc_info hash_or_key = nil
  Primitive.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 gc.rb, line 33
def self.start full_mark: true, immediate_mark: true, immediate_sweep: true
  Primitive.gc_start_internal full_mark, immediate_mark, immediate_sweep, false
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.

If the optional argument, hash, is given, it is overwritten and returned. This is intended to avoid probe effect.

This method is only expected to work on C Ruby.

# File gc.rb, line 169
def self.stat hash_or_key = nil
  Primitive.gc_stat hash_or_key
end

Returns current status of GC stress mode.

# File gc.rb, line 92
def self.stress
  Primitive.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 gc.rb, line 110
def self.stress=(flag)
  Primitive.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.

# File gc.rb, line 230
def self.verify_compaction_references(toward: nil, double_heap: false)
  Primitive.gc_verify_compaction_references(double_heap, toward == :empty)
end

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;
}