The change proposed in this PR improves the behavior of the JDK JNDI/LDAP
provider when running in a virtual thread. Currently, when an LDAP operation is
performed from a virtual thread context a pinned carrier thread is detected:
Thread[#29,ForkJoinPool-1-worker-1,5,CarrierThreads]
java.naming/com.sun.jndi.ldap.Connection.read
reply(Connection.java:444) <== monitors:1
java.naming/com.sun.jndi.ldap.LdapClient.ldapBind(LdapClient.java:369)
<== monitors:1
java.naming/com.sun.jndi.ldap.LdapClient.authenticate(LdapClient.java:196) <==
monitors:1
java.naming/com.sun.jndi.ldap.LdapCtx.connect(LdapCtx.java:2896) <==
monitors:1
To fix that monitor usages are replaced with `j.u.c` locks. All synchronized
blocks/methods have been replaced with locks even if it is only guarding memory
access - the motivation behind such a decision was to avoid an analysis of
scenarios where a mix of monitors and `j.u.c` locks is used.
There are three types of mechanical changes done in this PR:
1. Classes with `synchronized` blocks or `synchronized` methods have been
updated to include a new `ReentrantLock` field. These new fields are used to
replace `synchronized` blocks/methods.
1. classes that use notify/wait on object monitor have been updated to use
`ReentrantLock.Condition`s signal/await.
1. if one class `synchronized` on an instance of another class - the
`ReentrantLock` added in item (1) was made a package-protected to give access
to another class.
With the proposed changes pinned carrier threads are no longer detected during
execution of LDAP operations.
Testing: `jdk-tier1` to `jdk-tier3`, other `jndi/ldap` regression and JCK
naming tests show no failures.
-------------
Commit messages:
- revert incorrect changes in LdapCtx.addNamingListener, formatting and (c)
updates
- draft version
Changes: https://git.openjdk.org/jdk/pull/15526/files
Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=15526&range=00
Issue: https://bugs.openjdk.org/browse/JDK-8277954
Stats: 970 lines in 11 files changed: 394 ins; 101 del; 475 mod
Patch: https://git.openjdk.org/jdk/pull/15526.diff
Fetch: git fetch https://git.openjdk.org/jdk.git pull/15526/head:pull/15526
PR: https://git.openjdk.org/jdk/pull/15526
