Oracle International Corporation

Igor Veresov

Antonios Printezis

Paul Henry Hohensee

John Coomes

Methods and systems for garbage collection are described. In some embodiments, Garbage collector threads may maximize local accesses and minimize remote access by copying Young objects and Old objects differently. When copying a Young object, a garbage collector thread may determine the lgroup of the pool that contains the object and copy the object to a pool of the same lgroup. The garbage collector thread may spread Old objects among lgroups by copying Old objects to pools of the same lgroup as the respective garbage collector thread. Additional methods and systems are disclosed.

NUMA-aware garbage collection

System and Methods for non-uniform memory (NUMA) garbage collection are provided. Multiple memories and processors are categorized into local groups. A heap space is divided into multiple pools and stored in each of the memories. Garbage collection threads are assigned to each of the local groups. Garbage collection is performed using the garbage collection threads for objects contained in the pools using the garbage collector threads, memory, and processor assigned to each local group, minimizing remote memory accesses.

A system and method for providing direct socket input/output (I/O) for Java in a Java Virtual Machine (JVM) environment. During runtime, the system periodically garbage collects software objects in the Java memory space or heap. In accordance with an embodiment, the system provides a means to change the state of a thread performing the I/O which temporarily disallows garbage collection from taking place, thus guaranteeing that a receiving object in the heap does not move. The use of safepoints to prohibit GC from happening during the I/O call means that a global GC lock is not required. Non-blocking I/O is utilized, while prohibiting a thread from entering a GC safepoint during an I/O system call. The technique addresses disadvantages of previous methods by removing contended locks and by removing restrictions on allocation. In accordance with an embodiment, a special thread state can be used to prevent the thread from entering a GC safepoint.

Garbage collection safepoint system using non-blocking asynchronous I/O call to copy data when the garbage collection safepoint is not in progress or is completed

Growing community of inventors

Santa Clara, CA, United States of America

Igor Veresov