Review Request: 6896043: Zero fixes

[Vladimir Kozlov]

I would keep thread check.

Vladimir

Gary Benson wrote:
> Vladimir Kozlov wrote:
>> Gary Benson wrote:
>>> Vladimir Kozlov wrote:
>>>> hotspot/src/share/vm/runtime/os.hpp:
>>>> Can you explain why your changes is not the same as the comment
>>>> says?: ((_mem_serialize_page ^ addr) & -pagesize) == 0
>>> Basically because I didn't know if I'd need to make changes
>>> anywhere else, and I didn't want to break the other platforms.
>>> Should I change it to what the comment says?
>> I am concern about correctness of your code - page sizes could be
>> different.  I would prefer if your code will be similar to one in
>> is_poll_address().
> 
> So something like this:
> 
>   static bool    is_memory_serialize_page(JavaThread *thread, address addr) {
>     if (UseMembar) return false;
>     if (thread == NULL) return false;
>     return addr >= _mem_serialize_page && addr < (_mem_serialize_page + os::vm_page_size());
>   }
> 
> The "if (thread == NULL) return false;" would no longer be necessary,
> so it could either be retained to preserve the old behaviour or not.
> Which would you prefer?
> 
> Cheers,
> Gary
>