Integrated: 8280917: Simplify G1ConcurrentRefineThread activation

[Kim Barrett]

On Mon, 31 Jan 2022 00:08:10 GMT, Kim Barrett <kbarrett at openjdk.org> wrote:

> Please review this change to to G1ConcurrentRefineThreads to simplify the
> activation mechanism.
> 
> We split the class into two subclasses, one for the "primary" refinement
> thread and another class for the remaining refinement threads.
> 
> The secondary threads are changed to use Monitor-based waits and notifications
> with a supporting request flag.
> 
> The primary thread uses an atomic activation threshold that also serves as "is
> running" state.  This activation threshold is used by the write barrier
> support to determine whether the thread's semaphore needs to be signaled.
> That threshold is now in the primary refinement thread rather than in the
> dirty card queue set to simplify threshold management and somewhat reduce
> coupling.
> 
> Testing:
> mach5 tier1-3
> 
> Manual tests with refinement thread logging enabled to verify expected
> activations occur.

This pull request has now been integrated.

Changeset: 861f2797
Author:    Kim Barrett <kbarrett at openjdk.org>
URL:       https://git.openjdk.java.net/jdk/commit/861f2797f7d56ab185117f27dae2660af9250f6a
Stats:     396 lines in 7 files changed: 244 ins; 96 del; 56 mod

8280917: Simplify G1ConcurrentRefineThread activation

Reviewed-by: iwalulya, sjohanss

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PR: https://git.openjdk.java.net/jdk/pull/7282