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
.
internal constants
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;
}
Raises NoMemoryError
when allocating an instance of the given classes.
# File tmp/rubies/ruby-2.7.6/gc.rb, line 158
def self.compact
__builtin_rb_gc_compact
end
# File tmp/rubies/ruby-2.7.6/gc.rb, line 99
def self.count
__builtin_gc_count
end
# File tmp/rubies/ruby-2.7.6/gc.rb, line 63
def self.disable
__builtin_gc_disable
end
Disables garbage collection, returning true
if garbage collection was already disabled.
GC.disable #=> false GC.disable #=> true
# File tmp/rubies/ruby-2.7.6/gc.rb, line 51
def self.enable
__builtin_gc_enable
end
Enables garbage collection, returning true
if garbage collection was previously disabled.
GC.disable #=> false GC.enable #=> true GC.enable #=> false
# File tmp/rubies/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 information about the most recent garbage collection.
static VALUE
gc_malloc_allocated_size(VALUE self)
{
return UINT2NUM(rb_objspace.malloc_params.allocated_size);
}
Returns the size of memory allocated by malloc().
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);
}
Returns the number of malloc() allocations.
Only available if ruby was built with CALC_EXACT_MALLOC_SIZE
.
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;
}
No longer raises NoMemoryError
when allocating an instance of the given classes.
# File tmp/rubies/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
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 tmp/rubies/ruby-2.7.6/gc.rb, line 144
def self.stat hash_or_key = nil
__builtin_gc_stat hash_or_key
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 tmp/rubies/ruby-2.7.6/gc.rb, line 71
def self.stress
__builtin_gc_stress_get
end
Returns current status of GC
stress mode.
# File tmp/rubies/ruby-2.7.6/gc.rb, line 89
def self.stress=(flag)
__builtin_gc_stress_set_m flag
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
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 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_internal_consistency_m(VALUE dummy)
{
gc_verify_internal_consistency(&rb_objspace);
return Qnil;
}
Verify internal consistency.
This method is implementation specific. Now this method checks generational consistency if RGenGC is supported.
static VALUE
gc_verify_transient_heap_internal_consistency(VALUE dmy)
{
rb_transient_heap_verify();
return Qnil;
}
# File tmp/rubies/ruby-2.7.6/gc.rb, line 37
def garbage_collect full_mark: true, immediate_mark: true, immediate_sweep: true
__builtin_gc_start_internal full_mark, immediate_mark, immediate_sweep
end