RFR(M): 8219586: CodeHeap State Analytics processes dead nmethods

[Schmidt, Lutz]

Hi Tobias, 

I used the brackets for "optical separation", to emphasize what was added. There is no "hidden purpose". 

The comment attempts to explain why these fields are first initialized with NULL/false, although they are filled with "more meaningful" data shortly after.

I will remove the brackets and try to express my thoughts more clearly by rephrasing the comment. 

May I then regard this change as reviewed?

Thank you!
Lutz
 

On 04.09.20, 10:58, "Tobias Hartmann" <tobias.hartmann at oracle.com> wrote:

    Hi Lutz,

    hard to review but looks reasonable to me.

    In compiledMethod.cpp:72, the brackets and comment are confusing. Why should these fields be treated
    specially?

    Best regards,
    Tobias

    On 26.08.20 17:20, Schmidt, Lutz wrote:
    > Dear all, 
    > 
    > may I please request reviews for this fix/improvement to CodeHeap State Analytics. Explained in a nutshell it removes the last holes through which the analysis code could potentially access memory which is no longer associated with the entity being inspected.
    > 
    > There has been a long-lasting, off-list discussion with Erik Österlund until all pitfalls were identified and agreeable solutions were found. The important parts of that discussion are reflected in the bug comments. There are two major changes:
    > 
    >  1) All accesses to the CodeHeap are now protected by continuously holding the CodeCache_lock and, in addition, the Compile_lock. Information is aggregated in local data structures for later printing without holding the above locks.
    > 
    >  2) Printing the names of all code blobs has been disabled except for one operation mode where the locks can be held while printing.
    > 
    > Bug:    https://bugs.openjdk.java.net/browse/JDK-8219586
    > Webrev: https://cr.openjdk.java.net/~lucy/webrevs/8219586.02/
    > 
    > This change has JDK-8250635 (currently out for review) as a prerequisite. It will not compile without. 
    > 
    > Thank you!
    > Lutz
    >