RFR(T): 8251543: add mention of INFLATING() to share/oops/markWord.hpp header comment

[Kim Barrett]

> On Aug 13, 2020, at 5:16 PM, Daniel D. Daugherty <daniel.daugherty at oracle.com> wrote:
> 
> In a previous cleanup bug, we normalized src/share/runtime/synchronizer.cpp to
> use "stack-lock" instead of "stack lock" and other variants. I'm going to change
> the two "stack lock" uses to "stack-lock" below.
> 
> Dan

Looks good, and trivial.

> 
> 
> On 8/13/20 10:58 AM, Daniel D. Daugherty wrote:
>> Greetings,
>> 
>> I have a trivial comment addition to src/hotspot/share/oops/markWord.hpp.
>> 
>> Here's the bug:
>> 
>>     JDK-8251543 add mention of INFLATING() to share/oops/markWord.hpp header comment
>>     https://bugs.openjdk.java.net/browse/JDK-8251543
>> 
>> And here's the proposed fix:
>> 
>> $ hg diff
>> diff -r 73778bfbffe3 src/hotspot/share/oops/markWord.hpp
>> --- a/src/hotspot/share/oops/markWord.hpp    Thu Aug 13 10:02:35 2020 -0400
>> +++ b/src/hotspot/share/oops/markWord.hpp    Thu Aug 13 10:51:44 2020 -0400
>> @@ -86,6 +86,10 @@
>>  //    [ptr             | 11]  marked             used to mark an object
>>  //
>>  //    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().
>> 
>>  class BasicLock;
>>  class ObjectMonitor;
>> @@ -226,7 +230,7 @@
>>    bool is_being_inflated() const { return (value() == 0); }
>> 
>>    // Distinguished markword value - used when inflating over
>> -  // an existing stacklock.  0 indicates the markword is "BUSY".
>> +  // an existing stack lock.  0 indicates the markword is "BUSY".
>>    // Lockword mutators that use a LD...CAS idiom should always
>>    // check for and avoid overwriting a 0 value installed by some
>>    // other thread.  (They should spin or block instead.  The 0 value
>> 
>> 
>> Thanks, in advance, for any comments, questions or suggestions.
>> 
>> Dan