RFR (S) 8078438: Interpreter should support conditional card marks (UseCondCardMark)

Mikael Gerdin mikael.gerdin at oracle.com
Tue Apr 28 13:06:52 UTC 2015


On 2015-04-28 14:45, Andrew Haley wrote:
> On 04/28/2015 11:56 AM, Thomas Schatzl wrote:
>> Somewhat related, note that C2 adds a MemBarRelease before the actual
>> card table store (see StoreCMNode) I think to ensure store ordering (the
>> card mark must be visible after the reference write). So the given
>> aarch64 code seems to be missing something already.
>
> I don't think it's missing anything.  It has the barrier in the correct
> place when G1 is in use, and CMS isn't supposed to need one.

I think it does depend on StoreStore ordering, the field write must be 
visible if the dirty card byte is visible.

I don't know if that requires use of barriers or not in ARM-land.

/Mikael

>
> Andrew.
>


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