On Thu, 21 Apr 2022 11:35:57 GMT, Alan Bateman <[email protected]> wrote:
>> This is the implementation of JEP 425: Virtual Threads (Preview); TBD which
>> JDK version to target.
>>
>> We will refresh this PR periodically to pick up changes and fixes from the
>> loom repo.
>>
>> Most of the new mechanisms in the HotSpot VM are disabled by default and
>> require running with `--enable-preview` to enable.
>>
>> The patch has support for x64 and aarch64 on the usual operating systems
>> (Linux, macOS, and Windows). There are stubs (calling Unimplemented) for
>> zero and some of the other ports. Additional ports can be contributed via
>> PRs against the fibers branch in the loom repo.
>>
>> There are changes in many areas. To reduce notifications/mails, the labels
>> have been trimmed down for now to hotspot, serviceability and core-libs.
>> We'll add the complete set of labels when the PR is further along.
>>
>> The changes include a refresh of java.util.concurrent and ForkJoinPool from
>> Doug Lea's CVS. These changes will probably be proposed and integrated in
>> advance of this PR.
>>
>> The changes include some non-exposed and low-level infrastructure to support
>> the (in draft) JEPs for Structured Concurrency and Scope Locals. This is to
>> make life a bit easier and avoid having to separate VM changes and juggle
>> branches at this time.
>
> Alan Bateman has updated the pull request incrementally with one additional
> commit since the last revision:
>
> Refresh
src/java.base/share/classes/java/lang/ThreadLocal.java line 179:
> 177: private T get(Thread t) {
> 178: ThreadLocalMap map = getMap(t);
> 179: if (map != null && map != ThreadLocalMap.NOT_SUPPORTED) {
Due to the way `setInitialValue` is implemented, `getMap(t)` will currently be
called twice when `ThreadLocal`s are disabled.
--------------------------------------------------------------------------------
This method should probably be changed so that when `map ==
ThreadLocalMap.NOT_SUPPORTED`, it simply does:
return initialValue();
--------------------------------------------------------------------------------
Suggestion:
if (map != null) {
if (map == ThreadLocalMap.NOT_SUPPORTED) {
return initialValue();
}
src/java.base/share/classes/java/lang/ThreadLocal.java line 423:
> 421: * Construct a new map without a table.
> 422: */
> 423: ThreadLocalMap() {
It might be possible for this to be `private`:
Suggestion:
private ThreadLocalMap() {
-------------
PR: https://git.openjdk.java.net/jdk/pull/8166
