RFR: 8201800: Add support for adjusting heap addresses in a TLAB

[Per Liden]

On 04/18/2018 04:26 PM, Aleksey Shipilev wrote:
> On 04/18/2018 04:23 PM, Aleksey Shipilev wrote:
>> On 04/18/2018 04:05 PM, Per Liden wrote:
>>> This patch adds support for iterating over and adjusting heap addresses contained in TLABs. A user
>>> of this would be ZGC, which sometimes wants to adjust the color of those pointers. This patch adds a
>>> new function, ThreadLocalAllocBuffer::addresses_do(), which takes a function/functor and applies
>>> that to all addresses in the TLAB.
>>>
>>> Bug: https://bugs.openjdk.java.net/browse/JDK-8201800
>>> Webrev: http://cr.openjdk.java.net/~pliden/8201800/webrev.0
>>
>> Wait, how does this supposed to work? Don't you want to pass four arguments to f(...), not call f()
>> four times?
> 
> I misread. You want to update addresses *of* the TLAB itself, not *in* a memory covered by the TLAB.

Yep, that's right.

> 
> This looks fine to me.

Thanks for reviewing!

/Per

> 
> -Aleksey
> 
>