[9, P1] RFR (S/M): 8180048: Interned string and symbol table leak memory during parallel unlinking

[David Holmes]

On 12/05/2017 4:49 PM, Aleksey Shipilev wrote:
> On 05/12/2017 03:38 AM, David Holmes wrote:
>> On 12/05/2017 2:26 AM, Aleksey Shipilev wrote:
>>> Nits:
>>>
>>>  *) Modifier order?
>>>   176   BasicHashtableEntry<F>* volatile _free_list;
>>
>> _free_list is updated lock-free using Atomic::cmpxchg_ptr so it is appropriate
>> to mark it as being volatile.
>
> Of course. My comment was about the modifier _order_, see in the same file:

The order is critical for correctness.

>  176   BasicHashtableEntry<F>* volatile _free_list;
> ...
>  180   volatile int      _number_of_entries;
>
> I think Hotspot uses "volatile $type $id" everywhere I saw.

It's different for pointers:

BasicHashtableEntry<F>* volatile _free_list;

_free_list is a volatile pointer to a non-volatile entry

volatile BasicHashtableEntry<F>* _free_list;

_free_list is a non-volatile pointer to a volatile entry

volatile BasicHashtableEntry<F>* volatile _free_list;

_free_list is a volatile pointer to a volatile entry

(I don't claim all volatile decls in hotspot necessarily have this right!)

Cheers,
David

> Thanks,
> -Aleksey
>
>