jdk8-mips64-public/hotspot: src/share/vm/jfr/recorder/checkpoint/types/traceid/jfrTraceId.hpp@45c8de52649c (annotated)

src/share/vm/jfr/recorder/checkpoint/types/traceid/jfrTraceId.hpp@45c8de52649c (annotated)

src/share/vm/jfr/recorder/checkpoint/types/traceid/jfrTraceId.hpp

Tue, 02 Jun 2020 14:29:43 +0800

author: ddong
date: Tue, 02 Jun 2020 14:29:43 +0800
changeset 9941: 45c8de52649c
parent 9858: b985cbb00e68
permissions: -rw-r--r--

8246310: Clean commented-out code about ModuleEntry andPackageEntry in JFR
Reviewed-by: adinn

 /*
  * Copyright (c) 2011, 2018, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
  * under the terms of the GNU General Public License version 2 only, as
  * published by the Free Software Foundation.
  *
  * This code is distributed in the hope that it will be useful, but WITHOUT
  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  * version 2 for more details (a copy is included in the LICENSE file that
  * accompanied this code).
  *
  * You should have received a copy of the GNU General Public License version
  * 2 along with this work; if not, write to the Free Software Foundation,
  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  *
  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  * or visit www.oracle.com if you need additional information or have any
  * questions.
  *
  */
 #ifndef SHARE_VM_JFR_CHECKPOINT_TYPES_TRACEID_JFRTRACEID_HPP
 #define SHARE_VM_JFR_CHECKPOINT_TYPES_TRACEID_JFRTRACEID_HPP
 #include "jni.h"
 #include "jfr/utilities/jfrTypes.hpp"
 #include "memory/allocation.hpp"
 class ClassLoaderData;
 class Klass;
 class Method;
 class Thread;
 /*
  * JfrTraceId is a means of tagging, e.g. marking, specific instances as being actively in-use.
  * The most common situation is a committed event that has a field that is referring to a specific instance.
  * Now there exist a relation between an event (field) and an artifact of some kind.
  * We track this relation during runtime using the JfrTraceId mechanism in order to reify it into the chunk
  * where the event is finally written.
  *
  * It is the event commit mechanism that tags instances as in-use. The tag routines return the untagged traceid
  * as a mapping key, and the commit mechanism writes the key into the event field.
  * Consequently, the mechanism is opaque and not something a user needs to know about.
  * Indeed, the API promotes using well-known JVM concepts directly in events, such as having a Klass* as an event field.
  *
  * Tagging allows for many-to-one mappings of constants, lazy evaluation / collection of tags during chunk rotation
  * and concurrency (by using an epoch relative tagging scheme).
  *
  * JfrTraceId(s) have been added to support tagging instances of classes such as:
  *
  *   Klass (includes Method)
  *   ClassLoaderData
  *
  * These classes have been extended to include a _traceid field (64-bits).
  *
  * Each instance is uniquely identified by a type-relative monotonic counter that is unique over the VM lifecycle.
  * "Tagging an instance" essentially means to set contextually determined (by epoch) marker bits in the _traceid field.
  * The constants associated with a tagged instance is a set of which is determined by a constant type definition,
  * and these constants are then serialized in an upcoming checkpoint event for the relevant chunk.
  *
  * Note that a "tagging" is relative to a chunk. Having serialized the tagged instance, the tag bits are reset (for that epoch).
  * As mentioned previously, the returned traceid is always the untagged value.
  *
  * We also use the _traceid field in Klass to quickly identify (bit check) if a newly loaded klass is of type jdk.jfr.Event.
  * (see jfr/instrumentation/jfrEventClassTransformer.cpp)
  *
  *
  * _traceid bit layout and description planned to go here
  *
  *
  */
 class JfrTraceId : public AllStatic {
  public:
   static void assign(const Klass* klass);
   static void assign(const ClassLoaderData* cld);
   static traceid assign_thread_id();
   static traceid get(const Klass* klass);
   static traceid get(jclass jc);
   static traceid get(const Thread* thread);
   // tag construct as used, returns pre-tagged traceid
   static traceid use(const Klass* klass, bool leakp = false);
   static traceid use(jclass jc, bool leakp = false);
   static traceid use(const Method* method, bool leakp = false);
   static traceid use(const ClassLoaderData* cld, bool leakp = false);
   static void remove(const Klass* klass);
   static void restore(const Klass* klass);
   // set of event classes made visible to java
   static bool in_visible_set(const Klass* k);
   static bool in_visible_set(const jclass jc);
   // jdk.jfr.Event
   static bool is_jdk_jfr_event(const Klass* k);
   static bool is_jdk_jfr_event(const jclass jc);
   static void tag_as_jdk_jfr_event(const Klass* k);
   // jdk.jfr.Event subklasses
   static bool is_jdk_jfr_event_sub(const Klass* k);
   static bool is_jdk_jfr_event_sub(const jclass jc);
   static void tag_as_jdk_jfr_event_sub(const Klass* k);
   static void tag_as_jdk_jfr_event_sub(const jclass jc);
   static bool in_jdk_jfr_event_hierarchy(const Klass* k);
   static bool in_jdk_jfr_event_hierarchy(const jclass jc);
   // klasses that host an event
   static bool is_event_host(const Klass* k);
   static bool is_event_host(const jclass jc);
   static void tag_as_event_host(const Klass* k);
   static void tag_as_event_host(const jclass jc);
 };
 #endif // SHARE_VM_JFR_CHECKPOINT_TYPES_TRACEID_JFRTRACEID_HPP

Mercurial > jdk8-mips64-public > hotspot / annotate

src/share/vm/jfr/recorder/checkpoint/types/traceid/jfrTraceId.hpp@45c8de52649c (annotated)

src/share/vm/jfr/recorder/checkpoint/types/traceid/jfrTraceId.hpp