Sun Microsystems, Inc.

Apple Inc.

Derek R White

Ole Agesen

Marc R Tremblay

Guy Lewis Steele, Jr

James Michael O'Connor

Sanjay Vishin

Steven K Heller

David L Detlefs

Oliver W Steele

Neil Lawrence Mayle

Ross Charles Knippel

Steven Henry Strassmann

Jeremy A Jones

Y Srinivas Ramakrishna

Alex Garthwaite

Andrew L Shalit

Paige K Parsons

William W St Clair, Jr

Methods, systems, and articles of manufacture consistent with the present invention provide a program component including a set of instructions native to the system, include in the set of native instructions an instruction to maintain information on use of a particular object, and permit reuse of memory resources corresponding to the particular object based on an indication from a source that the particular object is no longer being used, the source being different from any source used to provide information on use of objects associated with non-native instructions of the program component. Additionally, garbage collection is not permitted during native code operations to read or write data in object fields because during such operations an indication exists that such collection may be inaccurate and could possibly reclaim or relocate objects referenced by native code though not specified as such in the native code stack and global variables.

Method, apparatus, and article of manufacture for facilitating resource management for applications having two types of program code

An object structure's header (,) allocates a two-bit synchronization-state field (,) solely to monitor data for implementing synchronization on that object. When the object is locked by a particular execution thread, or when one or more execution threads are waiting for a lock or notification on that object, its header contains a pointer to monitor resources in the form of a linked list of lock records (,) associated with the threads involved. The synchronization-state field (,) ordinarily contains an indication of whether such a linked list exists and, if so, whether its first member is associated with a thread that has a lock on the object. When a thread attempts to gain access to that linked list, it employs an atomic swap operation to place a special busy value in that lock-state field (,) and write its execution-environment pointer into the object's header (,). If the previous value of that field was not the special busy value, the thread uses the header's previous contents to perform its intended synchronization operation. Otherwise, it obtains that information through its own execution environment (,, or,) or that of the thread whose identifier the object header previously contained. When the thread completes its synchronization operation, it employs an atomic compare-and-swap operation to write the results into the object's header if that header still contains the thread identifier that the thread originally wrote there. Otherwise, it communicates that information to its successor thread if the thread identifier is different and thereby indicates that at least one successor is contending for access to the linked list.

Busy-wait-free synchronization

A graphical user interface comprises aspect and style elements for controlling the type of information associated with objects displayed on a display screen of a computer system when browsing through the objects. The aspect element controls the particular type of information displayed for an object on a portion of a window, called a pane, while the style element controls the types of information displayed for all objects within that pane.

Aspect and style elements of an improved graphical user interface

A partially relocated object identifier store including 'copy from' identifier and 'copy to' identifier storage accessible to write barrier logic allows the write barrier logic to maintain consistency between FromSpace and ToSpace instances of a partially relocated memory object without software trap handler overhead. Optional 'How far' indication storage facilitates differentiation by the write barrier logic between a copied portion and an uncopied portion of the partially relocated memory object. An optional 'mode' indication facilitates differentiation by the write barrier logic between a copy phase and a pointer update phase of relocation by the garbage collector implementation. In some embodiments, pointer update and copying phases may overlap. 'Copy to' identifier storage facilitates broadcast of a store-oriented memory access to the FromSpace instance to both FromSpace and ToSpace instances. Similarly, during pointer update, 'Copy to' and 'Copy From' identifier storage facilitate broadcast of a store-oriented memory access to either the FromSpace instance or the ToSpace instance to both FromSpace and ToSpace instances.

Bounded-pause time garbage collection system and method including write

A write barrier to stores into a partially relocated large or popular memory object facilitates bounded pause time implementations of relocating garbage collectors, including e.g., copying collectors, generational collectors, and collectors providing compaction. Such a write barrier allows a garbage collector implementation to interrupt relocation of large or popular memory objects so as to meet bounded pause time guarantees. A partially relocated object identifier store including 'copy from' identifier storage accessible to write barrier logic allows the write barrier logic to maintain consistency between FromSpace and ToSpace instances of a partially relocated memory object. 'Copy from' identifier storage allows the write barrier logic, or a trap handler responsive thereto, to broadcast a store-oriented memory access targeting the FromSpace instance to both FromSpace and ToSpace instances. Optional 'How far' indication storage facilitates differentiation by the write barrier logic between a copied portion and an uncopied portion of the partially relocated memory object.

A partially relocated object identifier store including 'copy from' and 'copy to' identifier storage accessible to write and read barrier logic allows the write and read barrier logic to selectively direct store- and load-oriented accesses to an appropriate FromSpace or ToSpace instance of a partially relocated memory object, in accordance with the memory object's partial relocation state. In some embodiments, the barriers trap to a partially relocated object trap handler. In other embodiments, the write barrier itself directs accesses without software trap handler overheads. Optional 'how far' indication storage facilitates differentiation by the barrier logic, or by the partially relocated object trap handler, between a copied portion and an uncopied portion of the partially relocated memory object.

Bounded-pause time garbage collection system and method including read

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Reading, MA, United States of America

Derek R White