Google Inc.

Hannes Payer

Daniel Kenneth Clifford

Benedikt Meurer

Michael Starzinger

Michael Vincent Stanton

Ben Titzer

Aspects of the subject technology relate to concurrent marking of objects in memory. A garbage collection process accesses objects in a marking deque. The objects have status indicators which can be unmarked, pending, processing, and marked. For each object in the marking deque, the garbage collection process determines whether the object is marked. If the object is not marked, the garbage collection process determines whether the object is pending. If the object is pending, the garbage collection process sets the object to processing. The garbage collection process adds objects referenced by the object to the marking deque and determines if the object is marked. If the object is marked already, the garbage collection process removes the referenced objects from the marking deque. If the object was not marked, the garbage collection process marks the object and processes the referenced objects. A mutator process may also update the status indicators for the objects.

Concurrent marking of location and shape changing objects

A computer-implemented method can include receiving a set of software instructions for execution by a computing device and compiling the set of software instructions to generate a set of executable instructions. The compiling can include identifying a first memory object allocation instruction. The method can also include executing the set of executable instructions, where the executing includes allocating, in a young garbage collection generation, a plurality of memory objects with the first memory object allocation instruction. The method can further include determining a survival rate of the plurality of memory objects allocated by the first memory object allocation instruction. Responsive to the survival rate being larger than a survival rate threshold, the method can include replacing, in the set of executable instructions, the first memory object allocation instruction with a second memory object allocation instruction that is configured to directly allocate memory objects in an old garbage collection generation.

Memory object pretenuring

A computer-implemented method for compilation of applications can include receiving a set of software instructions and traversing the set of software instructions based on a control-flow order of the set of software instructions. The traversing can include identifying a first allocation instruction in the set of software instructions, the first allocation instruction being configured to allocate a first amount of memory for a first object and identifying a second allocation instruction in the set of software instructions, the second allocation instruction being configured to allocate a second amount of memory for a second object. The method can include determining that the first allocation instruction dominates the second allocation instruction and, in response to the determining, combining the first allocation instruction and the second allocation instruction into a folded allocation instruction that allocates the first amount of memory and the second amount of memory in a single memory allocation operation.

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Munich, Germany

Hannes Payer