RFR: ZGC: Simplify the ZPage life cycle

Per Liden per.liden at oracle.com
Fri Mar 15 14:08:50 UTC 2019


On 03/14/2019 03:20 PM, Stefan Karlsson wrote:
> Hi Per,
> 
> Most of this look good.

Thanks for reviewing, Stefan!

[...]
>> 8220600: ZGC: Delete ZPages using ZSafeDelete
>> ---------------------------------------------
>> Remove the concept of deferred destruction of detached ZPages, and 
>> instead delete ZPages using ZSafeDelete.
>>
>> https://bugs.openjdk.java.net/browse/JDK-8220600
>> http://cr.openjdk.java.net/~pliden/8220600/webrev.0
>>
> 
> +  // Do not allow pages to be destroyed
> +  _page_allocator.enable_safe_delete();
> 
> +  // Allow pages to be destroyed
> +  _page_allocator.disable_safe_delete();
> 
> It sounds weird to disable safe deletes. Maybe rename these functions to 
> enable_deferred_deletes/disable_deferred_deletes?

I agree, renamed.

> 
> ------
> 
> We also need to use the safe delete mechanism when printing the page 
> table. That code gets exercised when run jcmd VM.info.

Good point, fixed.

Updated affected webrev:

8220599: ZGC: Introduce ZSafeDelete
-----------------------------------
http://cr.openjdk.java.net/~pliden/8220599/webrev.1-dff
http://cr.openjdk.java.net/~pliden/8220599/webrev.1


8220600: ZGC: Delete ZPages using ZSafeDelete
---------------------------------------------
http://cr.openjdk.java.net/~pliden/8220600/webrev.1-dff
http://cr.openjdk.java.net/~pliden/8220600/webrev.1


8220601: ZGC: Delete ZNMethodTableEntry arrays using ZSafeDelete
----------------------------------------------------------------
http://cr.openjdk.java.net/~pliden/8220601/webrev.1-dff
http://cr.openjdk.java.net/~pliden/8220601/webrev.1


/Per


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