RFR(T): 8252125: add an "inflating" entry to the "table" of bit patterns in share/oops/markWord.hpp

[Thomas Schatzl]

Hi,

On 20.08.20 22:56, Daniel D. Daugherty wrote:
> Greetings,
> 
> I have a trivial fix to add more clarification to markWord bit patterns.
> 
> Here's the bug report:
> 
>      JDK-8252125 add an "inflating" entry to the "table" of bit patterns in
>                  share/oops/markWord.hpp
>      https://bugs.openjdk.java.net/browse/JDK-8252125
> 
> And here's the context diff for the trivial change itself:
> 
> $ hg diff -r qparent
> diff -r 8f73aeccb27c src/hotspot/share/oops/markWord.hpp
> --- a/src/hotspot/share/oops/markWord.hpp    Thu Aug 20 11:12:00 2020 -0700
> +++ b/src/hotspot/share/oops/markWord.hpp    Thu Aug 20 16:39:11 2020 -0400
> @@ -84,12 +84,13 @@
>   //    [header      | 0 | 01]  unlocked           regular object header
>   //    [ptr             | 10]  monitor            inflated lock (header 
> is wapped out)
>   //    [ptr             | 11]  marked             used to mark an object
> +//    [0 ............ 0| 00]  inflating          inflation in progress
>   //
>   //    We assume that stack/thread pointers have the lowest two bits 
> cleared.
>   //
> -//  - INFLATING() is a distinguished markword value that is used when
> -//    inflating an existing stack-lock into an ObjectMonitor. See below
> -//    for is_being_inflated() and INFLATING().
> +//  - INFLATING() is a distinguished markword value of all zeros that is
> +//    used when inflating an existing stack-lock into an ObjectMonitor.
> +//    See below for is_being_inflated() and INFLATING().
> 
>   class BasicLock;
>   class ObjectMonitor;
> 
> Thanks, in advance, for any comments, questions or suggestions.
> 

   lgtm and trivial.

Thomas