Bug #16900
closedDisposable call-cache introduced memory leak
Description
b9007b6c548f91e88fd3f2ffa23de740431fa969 (Introduce disposable call-cache) introduced a memory leak for classes that include or prepend modules. Taking the example memory leak script used in the commit message for 5922c954614e5947a548780bb3b894626affe6dd:
module M; def bar; end; end
loop{
Class.new do
def foo; end
prepend M
end
}
There is unbounded growth:
jeremy 56984 0.0 0.1 59540 14940 p2 S+ 5:15PM 0:00.19 ruby example.rb
jeremy 56984 0.0 0.1 61852 18640 p2 S+ 5:15PM 0:00.40 ruby example.rb
jeremy 56984 0.0 0.1 62700 19940 p2 S+ 5:15PM 0:00.62 ruby example.rb
jeremy 56984 0.0 0.1 63696 21364 p2 S+ 5:15PM 0:00.83 ruby example.rb
jeremy 56984 4.1 0.1 64632 22748 p2 S+ 5:15PM 0:01.05 ruby example.rb
jeremy 56984 4.1 0.1 65664 24188 p2 S+ 5:15PM 0:01.26 ruby example.rb
jeremy 56984 4.1 0.2 66632 25432 p2 S+ 5:15PM 0:01.47 ruby example.rb
jeremy 56984 4.1 0.2 67484 26552 p2 S+ 5:15PM 0:01.70 ruby example.rb
jeremy 56984 8.5 0.2 68456 27772 p2 S+ 5:15PM 0:01.92 ruby example.rb
jeremy 56984 8.5 0.2 69536 29164 p2 S+ 5:15PM 0:02.14 ruby example.rb
jeremy 56984 8.5 0.2 70424 30252 p2 S+ 5:15PM 0:02.36 ruby example.rb
This issue appears to be limited to classes that include or prepend modules.
- Same memory leak when switching from
prepend
toinclude
- No memory leak when switching from
Class.new
toModule.new
- No memory leak when removing the
prepend
- No memory leak when removing the
prepend
and subclassing the class.
Updated by jeremyevans0 (Jeremy Evans) almost 4 years ago
Using the following program, I have determined that Ruby isn't leaking objects according to ObjectSpace.count_objects
, so it is probably leaking some other memory.
module M; def bar; end; end
h = nil
h2 = ObjectSpace.count_objects
require 'objspace'
100.times { |i|
10000.times {
Class.new do
def foo; end
include M
end
}
GC.start
h = h2
h2 = ObjectSpace.count_objects
h2.each do |k,v|
p [i, k, v, h[k]] if h[k] != v
end
GC.start
}
Output from the program:
[0, :TOTAL, 10601, 9786]
[0, :FREE, 4874, 1823]
[0, :T_CLASS, 440, 436]
[0, :T_STRING, 2420, 4506]
[0, :T_ARRAY, 112, 259]
[0, :T_HASH, 5, 7]
[0, :T_DATA, 111, 128]
[0, :T_IMEMO, 2565, 2554]
[0, :T_ICLASS, 27, 26]
[1, :FREE, 4866, 4874]
[1, :T_HASH, 8, 5]
[1, :T_DATA, 112, 111]
[1, :T_IMEMO, 2569, 2565]
[2, :FREE, 4865, 4866]
[2, :T_HASH, 9, 8]
This shows that after the 3rd iteration, object counts remain the same.
Updated by ko1 (Koichi Sasada) almost 4 years ago
Great report!
https://github.com/ruby/ruby/pull/3128
Updated by ko1 (Koichi Sasada) almost 4 years ago
- Status changed from Open to Closed
Applied in changeset git|cbd45af2a9bec871ee023e6be57c5f32b22280fe.
fix memory leak of ccs
rb_callable_method_entry() creates ccs entry in cc_tbl, but this
code overwrite by insert newly created ccs and overwrote ccs never
freed.
[Bug #16900]