On Fri, 27 Jan 2023 20:50:32 GMT, Daniel D. Daugherty <dcu...@openjdk.org> wrote:
>> Roman Kennke has updated the pull request with a new target base due to a >> merge or a rebase. The pull request now contains 86 commits: >> >> - Merge branch 'master' into JDK-8291556-v2 >> - Revert UseFastLocking to default to off >> - Change log message inflate(locked) -> inflate(has_locker) >> - Properly set ZF on anon-check path; avoid some conditional branches >> - Use testb when testing for anon owner in fast-path >> - Merge branch 'master' into JDK-8291555-v2 >> - In x86_32 C2 fast_lock(), CAS thread directly, instead of CASing >> stack-pointer and then storing thread >> - x86 part of optimization to check for anon owner >> - Optimize the check-for-anon-owner fast-path >> - Merge remote-tracking branch 'origin/JDK-8291555-v2' into JDK-8291555-v2 >> - ... and 76 more: https://git.openjdk.org/jdk/compare/da80e7a4...784b361c > > src/hotspot/share/runtime/synchronizer.cpp line 1336: > >> 1334: // Success! Return inflated monitor. >> 1335: if (own) { >> 1336: assert(current->is_Java_thread(), "must be: checked in >> is_lock_owned()"); > > `is_lock_owned()` currently does this: > > > static bool is_lock_owned(Thread* thread, oop obj) { > assert(UseFastLocking, "only call this with fast-locking enabled"); > return thread->is_Java_thread() ? > reinterpret_cast<JavaThread*>(thread)->lock_stack().contains(obj) : false; > } > > > so I would not say "checked in is_locked_owned()" since `is_locked_owned()` > does > not enforce that the caller is a JavaThread. If it's not a Java thread, `is_lock_owned()` returns `false`, and we wouldn't end up in the `if (own)` branch. ------------- PR: https://git.openjdk.org/jdk/pull/10907
