RFR: 8253478: (se) epoll Selector should use eventfd for wakeup instead of pipe [v5]

[Michael McMahon]

On Tue, 19 Jan 2021 21:59:13 GMT, Brian Burkhalter <bpb at openjdk.org> wrote:

>> Please review this change which modifies the Linux `epoll(7)`-based `Selector` to use `eventfd(2)` instead of `pipe(2)` in its wakeup mechanism. The change passes all tier 1-tier 3 tests on Linux. Based on rudimentary testing, there does not appear to be any appreciable change in performance. One improvement however is that only one file descriptor instead of two is used for the wakeup. No test is included as the code is covered well by existing tests.
>
> Brian Burkhalter has updated the pull request incrementally with one additional commit since the last revision:
> 
>   8253478: clean up comment in micro

src/java.base/linux/classes/sun/nio/ch/EPollSelectorImpl.java line 89:

> 87:         }
> 88: 
> 89:         // register one end of the socket pair for wakeups

I guess the comment at line 89 no longer applies.

-------------

PR: https://git.openjdk.java.net/jdk/pull/2082