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Module: GC

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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 Profiler.

Constant Summary

Class Attribute Summary

Class Method Summary

Instance Method Summary

Class Attribute Details

.stressBoolean (rw)

Returns current status of GC stress mode.

.stress=(flag) ⇒ flag (rw)

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 a fixnum bit-ORed following flags.

0x01:: no major GC
0x02:: no immediate sweep
0x04:: full mark after malloc/calloc/realloc

Class Method Details

.add_stress_to_class(*args)

.countInteger

The number of times GC occurred.

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

.disableBoolean

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

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

.enableBoolean

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

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

.latest_gc_infoGC .latest_gc_info(hash) ⇒ Hash .latest_gc_info(:major_by) ⇒ :malloc

Returns information about the most recent garbage collection.

.malloc_allocated_sizeInteger

Returns the size of memory allocated by malloc().

Only available if ruby was built with CALC_EXACT_MALLOC_SIZE.

.malloc_allocationsInteger

Returns the number of malloc() allocations.

Only available if ruby was built with CALC_EXACT_MALLOC_SIZE.

.remove_stress_to_class(*args)

#startnil #garbage_collectnil #start(full_mark: true, immediate_sweep: true) ⇒ nil #garbage_collect(full_mark: true, immediate_sweep: true) ⇒ nil
Also known as: #garbage_collect

Initiates garbage collection, unless 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.

.statHash .stat(hash) ⇒ Hash .stat(:key) ⇒ Numeric

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_swept_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.

.verify_internal_consistencynil

Verify internal consistency.

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

Instance Method Details

#startnil #garbage_collectnil #start(full_mark: true, immediate_sweep: true) ⇒ nil #garbage_collect(full_mark: true, immediate_sweep: true) ⇒ nil

Alias for .start.