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
GC
build options
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.
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.
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.
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 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
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.
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.
Returns current status of GC
stress mode.
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 230 def self.verify_compaction_references(toward: nil, double_heap: false) Primitive.gc_verify_compaction_references(double_heap, toward == :empty) 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.
Ruby Core © 1993–2020 Yukihiro Matsumoto
Licensed under the Ruby License.
Ruby Standard Library © contributors
Licensed under their own licenses.