Re: RFR: 8266936: Add a finalization JFR event [v11]
On Thu, 23 Sep 2021 22:35:26 GMT, Coleen Phillimore wrote: >> Markus Grönlund has updated the pull request incrementally with two >> additional commits since the last revision: >> >> - remove rehashing and rely on default grow_hint for table resize >> - mtStatistics > > src/hotspot/share/jfr/periodic/jfrFinalizerStatisticsEvent.cpp line 26: > >> 24: >> 25: #include "precompiled.hpp" >> 26: #if INCLUDE_MANAGEMENT > > With precompiled headers turned off, this gets a compilation error: > error: "INCLUDE_MANAGEMENT" is not > defined, evaluates to 0 [-Werror=undef] Thanks, I missed submitting a few no-precompiled header builds. Fixed now. - PR: https://git.openjdk.java.net/jdk/pull/4731
Re: RFR: 8266936: Add a finalization JFR event [v11]
On Mon, 13 Sep 2021 17:12:49 GMT, Markus Grönlund wrote: >> Greetings, >> >> Object.finalize() was deprecated in JDK9. There is an ongoing effort to >> replace and mitigate Object.finalize() uses in the JDK libraries; please see >> https://bugs.openjdk.java.net/browse/JDK-8253568 for more information. >> >> We also like to assist users in replacing and mitigating uses in non-JDK >> code. >> >> Hence, this changeset adds a periodic JFR event to help identify which >> classes are overriding Object.finalize(). >> >> Thanks >> Markus > > Markus Grönlund has updated the pull request incrementally with two > additional commits since the last revision: > > - remove rehashing and rely on default grow_hint for table resize > - mtStatistics src/hotspot/share/jfr/periodic/jfrFinalizerStatisticsEvent.cpp line 26: > 24: > 25: #include "precompiled.hpp" > 26: #if INCLUDE_MANAGEMENT With precompiled headers turned off, this gets a compilation error: error: "INCLUDE_MANAGEMENT" is not defined, evaluates to 0 [-Werror=undef] - PR: https://git.openjdk.java.net/jdk/pull/4731
Re: RFR: 8266936: Add a finalization JFR event [v11]
On Fri, 17 Sep 2021 12:02:32 GMT, Coleen Phillimore wrote: >> Markus Grönlund has updated the pull request incrementally with two >> additional commits since the last revision: >> >> - remove rehashing and rely on default grow_hint for table resize >> - mtStatistics > > src/hotspot/share/runtime/mutexLocker.cpp line 323: > >> 321: >> 322: #if INCLUDE_JFR >> 323: def(JfrMsg_lock , PaddedMonitor, leaf-1, true, >> _safepoint_check_always); // -1 because the ConcurrentHashTable resize lock >> is leaf > > The ConcurrentHashTable_lock is a lock that doesn't check for safepoints, so > if you take this lock out while checking for safepoints, it should assert > when called from a JavaThread, which makes me think it's not called from a > JavaThread and should be _safepoint_check_never. > _resize_lock = > new Mutex(Mutex::nosafepoint-2, "ConcurrentHashTableResize_lock", > Mutex::_safepoint_check_never); > In my change, this is the ranking for ConcurrentHashTableResize_lock, so this > should be nosafepoint-3 if you check in after I do. Thanks, the JfrMsg_lock is acquired normally with safepoint checks when the JFR system needs to issue synchronous, blocking operations. Asynchronous operations, like message notifications, only attempt a try_lock() to avoid blocking in the case the lock is contended. The ConcurrentHashTable_lock is held during table iteration to prevent resizes from happening. Fortunately, the callback processing will only post asynchronous messages (like "Buffer full") and therefore will not reach the safepoint check. - PR: https://git.openjdk.java.net/jdk/pull/4731
Re: RFR: 8266936: Add a finalization JFR event [v11]
On Mon, 13 Sep 2021 17:12:49 GMT, Markus Grönlund wrote: >> Greetings, >> >> Object.finalize() was deprecated in JDK9. There is an ongoing effort to >> replace and mitigate Object.finalize() uses in the JDK libraries; please see >> https://bugs.openjdk.java.net/browse/JDK-8253568 for more information. >> >> We also like to assist users in replacing and mitigating uses in non-JDK >> code. >> >> Hence, this changeset adds a periodic JFR event to help identify which >> classes are overriding Object.finalize(). >> >> Thanks >> Markus > > Markus Grönlund has updated the pull request incrementally with two > additional commits since the last revision: > > - remove rehashing and rely on default grow_hint for table resize > - mtStatistics src/hotspot/share/runtime/mutexLocker.cpp line 323: > 321: > 322: #if INCLUDE_JFR > 323: def(JfrMsg_lock , PaddedMonitor, leaf-1, true, > _safepoint_check_always); // -1 because the ConcurrentHashTable resize lock > is leaf The ConcurrentHashTable_lock is a lock that doesn't check for safepoints, so if you take this lock out while checking for safepoints, it should assert when called from a JavaThread, which makes me think it's not called from a JavaThread and should be _safepoint_check_never. _resize_lock = new Mutex(Mutex::nosafepoint-2, "ConcurrentHashTableResize_lock", Mutex::_safepoint_check_never); In my change, this is the ranking for ConcurrentHashTableResize_lock, so this should be nosafepoint-3 if you check in after I do. - PR: https://git.openjdk.java.net/jdk/pull/4731
Re: RFR: 8266936: Add a finalization JFR event [v11]
> Greetings, > > Object.finalize() was deprecated in JDK9. There is an ongoing effort to > replace and mitigate Object.finalize() uses in the JDK libraries; please see > https://bugs.openjdk.java.net/browse/JDK-8253568 for more information. > > We also like to assist users in replacing and mitigating uses in non-JDK code. > > Hence, this changeset adds a periodic JFR event to help identify which > classes are overriding Object.finalize(). > > Thanks > Markus Markus Grönlund has updated the pull request incrementally with two additional commits since the last revision: - remove rehashing and rely on default grow_hint for table resize - mtStatistics - Changes: - all: https://git.openjdk.java.net/jdk/pull/4731/files - new: https://git.openjdk.java.net/jdk/pull/4731/files/fd86899f..62592daf Webrevs: - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=4731&range=10 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=4731&range=09-10 Stats: 258 lines in 6 files changed: 25 ins; 197 del; 36 mod Patch: https://git.openjdk.java.net/jdk/pull/4731.diff Fetch: git fetch https://git.openjdk.java.net/jdk pull/4731/head:pull/4731 PR: https://git.openjdk.java.net/jdk/pull/4731
