Oracle International Corporation

Jorn Bender Vernee

Maurizio Cimadamore

James Malcolm Laskey

Vladimir Vitalyevich Ivanov

Techniques for transitioning between memory segment views include: instantiating a first memory segment view that confines access to a memory segment to a first thread; receiving a request to transition ownership of the memory segment to a second thread; responsive to receiving the request to transition ownership of the memory segment to the second thread: instantiating a second memory segment view that permits access to the memory segment by the second thread; copying metadata from the first memory segment view to the second memory segment view; terminating the first memory segment view, to prevent access to the memory segment via the first memory segment view.

Transitioning between thread-confined memory segment views and shared memory segment views

Techniques for representing a native function using an executable reference are disclosed. The system receives an instruction to create an executable reference for a native function, including a method type comprising a method signature corresponding to the executable reference, and a function description including (a) a memory layout corresponding to data returned by the function and (b) memory layouts corresponding to parameters required by the function. The system selects an application binary interface (ABI). The system generates code that, for each parameter, of the one or more parameters required by the function, converts the parameter from a value formatted for use by a Java Virtual machine to a value formatted for use in the native function, based on the selected ABI. Responsive to invocation of the executable reference, the generated code and the native function may be executed.

Modeling foreign functions using executable references

Techniques for reducing overhead in native function calls are disclosed. The system may receive a method invocation instruction for invoking a particular method. The method invocation instruction includes a function descriptor, a method type, and an application binary interface (ABI) descriptor. The function descriptor includes a memory layout corresponding to any data returned by the function and memory layouts corresponding to each argument for the particular method. The system can select an ABI for processing the particular method based on the received ABI descriptor. The system can further associate each argument with a corresponding particular physical register into which the argument is to be loaded. The particular register is selected based on at least the selected ABI and the function descriptor. The system can cause a virtual machine to move each argument into the corresponding associated physical register.

Optimizing execution of foreign method handles on a virtual machine

Techniques for reducing unsafe memory access, particularly when interacting with native libraries, are disclosed. The system may receive a memory address. The system may determine that the received memory address is not associated with an existing memory segment. The system selects a particular memory segment, of a plurality of memory segments. The memory segment may have a length of zero and a size corresponding to a size of a native heap. The system may return a reference to the particular memory segment.

Methods for reducing unsafe memory access when interacting with native libraries

Techniques for transitioning between thread-confined memory segments and shared memory segments are disclosed. The system may instantiate a confined memory segment view. The confined memory segment view confines access to a memory segment to a particular thread. The system may further receive a request to change access permissions for the confined memory segment to allow access by a first set of one or more threads. Responsive to receiving the request to change access permissions for the confined memory segment, the system may instantiate a new memory segment view, wherein the new memory segment view permits access to the memory segment by the first set of one or more threads. The system may also copy metadata from the confined memory segment view to the new memory segment view. The system may de-allocate the memory segment in response to determining that there are no memory segment views associated with the memory segment.

Techniques for accessing off-heap memory are disclosed. The system may receive a memory segment layout definition for a memory segment in a physical memory of a machine. The memory segment layout definition defines a number of elements and a number of sub-elements in each element of the plurality of elements. The system may allocate the particular memory segment in the physical memory and may store a reference to a position of a sub-element. The system may receive a request to access a first sub-element of a particular element of the plurality of elements. Based on the request, the system may identify the memory segment corresponding to the plurality of elements, identify the particular element of the plurality of elements, identify the first sub-element of the plurality of elements based the position of the first sub-element, and execute an Input or Output (IO) operation corresponding to the request.

Growing community of inventors

Leiden, Netherlands

Jorn Bender Vernee