Reviewed-by: rehn, stuefe, dcubed, sspitsyn

Reviewed-by: tschatzl, pliden

Reviewed-by: andrew

Summary: small code improvements for increased robustness
Reviewed-by: acorn, coleenp
Contributed-by: michael.haupt@oracle.com

Reviewed-by: andrew

Summary: partially revert JDK-8238589
Reviewed-by: shade

Reviewed-by: shade, andrew

Reviewed-by: shade, apetushkov

Reviewed-by: dcubed, coleenp

Summary: Avoid use of lambdas and StringJoiner so GenerateJfrFiles builds with OpenJDK 7
Reviewed-by: shade

Reviewed-by: mgronlun

Reviewed-by: phh

8227605: Kitchensink fails "assert((((klass)->trace_id() & (JfrTraceIdEpoch::leakp_in_use_this_epoch_bit())) != 0)) failed: invariant"
Reviewed-by: dholmes, dcubed, egahlin

Reviewed-by: jbachorik

Reviewed-by: egahlin, rwestberg

8227011: Starting a JFR recording in response to JVMTI VMInit and / or Java agent premain corrupts memory
Reviewed-by: egahlin, rwestberg

Reviewed-by: mgronlun

Reviewed-by: dcubed, dholmes

Reviewed-by: neugens

Reviewed-by: clanger

Reviewed-by: gziemski, mgronlun

Reviewed-by: mgronlun, mikael

Reviewed-by: rehn, sgehwolf

Reviewed-by: redestad, egahlin

Reviewed-by: mgronlun

Reviewed-by: pliden

Reviewed-by: mgronlun

Reviewed-by: mgronlun

Reviewed-by: mgronlun, egahlin

Reviewed-by: mgronlun, dholmes

Reviewed-by: kbarrett, dholmes, dcubed, egahlin

Reviewed-by: mgronlun

Summary: Use notify_unload_class() to post JFR class unload events instead of doing a separate traversal of the class loader data graph
Reviewed-by: lfoltan, coleenp, mgronlun, egahlin

Reviewed-by: mgronlun

Reviewed-by: dholmes, alanb, rriggs

Reviewed-by: jbachorik

Reviewed-by: neugens

8223689: Add JFR Thread Sampling Support
8223690: Add JFR BiasedLock Event Support
8223691: Add JFR G1 Region Type Change Event Support
8223692: Add JFR G1 Heap Summary Event Support
Summary: Backport JFR from JDK11, additional fixes
Reviewed-by: neugens, apetushkov
Contributed-by: denghui.ddh@alibaba-inc.com

Reviewed-by: shade, mdoerr

Summary: added back code accidentally removed during push of JDK-8223147
Reviewed-by: neugens