International Business Machines Corporation

Karl Michael Taylor

Michael K Gschwind

Brian William Thompto

Giles R Frazier

Younes Manton

Peter Wiebe Burka

Graham Alan Chapman

Daniel J Heidinga

Vijay Sundaresan

Angela Lin

Ryan Andrew Sciampacone

Trent Gray-Donald

Charles Robert Gracie

Marcel Mitran

Andrew Russell Low

Jeffrey Michael Disher

Gavin Rolleston

Thomas Mark Walter Bottomley

Kishor V Patil

Olivier P Thomann

Ivan Sham

A method and apparatus for garbage collection is disclosed herein. The method includes performing a garbage collection process without pausing execution of a runtime environment. The method also includes executing a first CPU instruction to load a first pointer that points to a first location in a first region of memory, where the first region of memory is undergoing garbage collection. The method also includes moving a first object pointed to by the first pointer from the first location in memory to a second location in memory.

Multi-section garbage collection

A method and apparatus for garbage collection is disclosed herein. The method includes specifying a load-monitored region within a memory managed by a run-time environment, enabling a load-monitored event-based branch configured to occur responsive to executing a first type of CPU instruction to load a pointer that points to a first location in the load-monitored region, performing a garbage collection process in background without pausing executing in the run-time environment, executing a CPU instruction of the first type to load a pointer that points to the first location in the load-monitored region, and responsive to triggering a load-monitored event-based branch, moving an object pointed to by the pointer with a handler from the first location in memory to a second location in memory.

Multi-section garbage collection method

The embodiments relate to a computer system, computer program product and method for managing a garbage collection process. Processing control is obtained based on execution of a load instruction and a determination that an object pointer to be loaded indicates a location within a selected portion of memory undergoing a garbage collection process. The determination includes identifying a base address and size of a first memory block subject to the garbage collection, and assigning a binary value to each first memory block section. An image of the load instruction is obtained and a pointer address is calculated from the image. It is determined whether the object pointer is to be modified. The object pointer is modified and stored in a selected location.

Apparatus for a garbage collection is disclosed herein. The apparatus includes a processor that includes a load-monitored region register. A memory stores program code, which, when executed on the processor performs an operation for garbage collection, the operation includes specifying a load-monitored region within a memory managed by a runtime environment; enabling a load-monitored event-based branch configured to occur responsive to executing a first type of CPU instruction to load a pointer that points to a first location in the load-monitored region; performing a garbage collection process in background without pausing executing in the runtime environment; executing a CPU instruction of the first type to load a pointer that points to the first location in the load-monitored region; responsive to triggering a load-monitored event-based branch, moving an object pointed to by the pointer with a handler from the first location in memory to a second location in memory.

The embodiments relate to a method for managing a garbage collection process. The method includes executing a garbage collection process on a memory block of user address space. A load instruction is run. Running the load instruction includes loading content of a storage location into a processor. The loaded content corresponds to a memory address. It is determined if the garbage collection process is being executed at the memory address. The load instruction is diverted to a process to move an object at the memory address to a location outside of the memory block in response to determining that the garbage collection process is being executed at the first memory address. The load instruction is continued in response to determining that the garbage collection process is not being executed at the memory address.

Method and apparatus for managing memory is disclosed herein. In one embodiment, the method includes specifying a first load-monitored region within a memory, configuring a performance monitor to count object pointer accessed events associated with the first load-monitored region, executing a CPU instruction to load a pointer that points to a first location in the memory, responsive to determining that the first location is within the first load-monitored region, triggering an object pointer accessed event, updating a count of object pointer accessed events in the performance monitor, and performing garbage collection on the first load-monitored region based on the count of object pointer accessed events.

Scheme for determining data object usage in a memory region

The embodiments relate to a computer system, computer program product and method for managing a garbage collection process. Processing control is obtained based on execution of a load instruction and a determination that an object pointer to be loaded indicates a location within a selected portion of memory undergoing a garbage collection process. The determination includes identifying a base address and size of a first memory block subject to the garbage collection, subdividing the first memory block into sections, assigning a binary value to each section, and determining if the first memory block corresponds to the enabled section. An image of the load instruction is obtained and a pointer address is calculated from the image. The object pointer is read and it is determined whether the object pointer is to be modified. The object pointer is modified and stored in a selected location.

Embodiments of the present invention disclose a method, system, and computer program product for a JNI object access system. A computer receives a JNI reference and obtains the pointer data and call site of the referenced object. The computer determines whether a record of the object and call site exist and, if not, the respective records are created. The computer applies a heuristic analysis of the object and call site in which it determines whether the object is larger than a threshold size, whether the object is part of a particular region of the heap, whether the call site is associated with a read-only or a read-write function, and whether the object or call site has caused more non-moving garbage collections than a threshold number. Based on the heuristic, the computer either copies the object data or pins the object and any non-moving garbage collections are recorded.

JNI object access

A method for creating an enhanced array is provided. An enhanced compiler generates an instrumented class file for an enhanced array class. The enhanced array class comprises at least one element class. The enhanced runtime loads the instrumented class file of the enhanced array class. The enhanced runtime loads a class file corresponding to the element class of the enhanced array class, and builds an internal data structure corresponding to the enhanced array class. An amount of memory storage is calculated for storing the enhanced array instance, and the amount of memory storage is allocated.

Enhanced array class

Enhanced java array

An illustrative embodiment for serialization of pre-initialized objects receives a source code definition of a class, identifies a set of constants associated with the class in the source code to form a set of identified constants, creates a result object corresponding to each constant in the set of identified constants, and compiles the source code into a compiled form of the class. The illustrative embodiment further serializes each result object into a resource file associated with the class to form a set of serialized objects and replaces, in the compiled form of the class, each reference to a respective constant associated with the class from the set of identified constants with a corresponding dynamic instruction using a respective serialized object in the set of serialized objects.

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Kanata, Canada

Karl Michael Taylor