Re: [Tarantool-patches] [PATCH luajit v2] test: fix flaky OOM error frame test

[Sergey Bronnikov via Tarantool-patches <tarantool-patches@dev.tarantool.org>]

Igor,


thanks for explanation!

On 11/20/23 17:53, Igor Munkin wrote:
> Sergey,
>
> On 18.11.23, Sergey Bronnikov via Tarantool-patches wrote:
>> Hello, Max
>>
>> LGTM with a question below
>>
>>
>> On 11/9/23 16:45, Maksim Kokryashkin wrote:
> <snipped>
>
>>> +collectgarbage()
>> Probably it is obvious, but I don't get it.
>>
>> Usually for forcing garbage collecting one need call `collectgarbage()` two
>> times:
>>
>> for mark and sweep. You call it single time, why?
> The reason of two consequent <collectgarbage> calls is not for "mark and
> sweep" but rather for "full GC cycle + finalization of the resurrected
> objects". The first call implements full (even 1.5) GC cycle; as a
> result of this call some *objects* can be *released*, but the
> corresponding *memory* is preserved in another list (gc->mmudata, IIRC)
> to properly finalize the object (i.e. call __gc metamethod). Hence, the
> second call finally releases the memory for the objects resurrected
> within the sweep phase of the first call.
>
> Since Max allocates plain FFI objects with no <ffi.gc> finalizers,
> there is no need in the second <collectgarbage> call here.
>
> <snipped>
>