Oracle America, Inc.

Oracle International Corporation

Erez Landau

Dean R E Long

Nedim Fresko

Oleg A Pliss

A system that allocates memory for immutable data on a computing device. The system allocates a memory region on the computing device to store immutable data for an executing application. This memory region is smaller than the immutable data for the application. When the system subsequently receives a request to access a block of immutable data for the application, the system allocates space in this memory region for the block, and proceeds to load the block into the memory region. If at a later time the space occupied by this first block is needed for another block, the system unloads and discards the first block. If a subsequent operation needs to use information in the first block, the system regenerates the block by transforming raw data associated with the block into a form that can be directly accessed by the application, and then reloads the block into the memory region.

Method and apparatus for allocating memory for immutable data on a computing device

One embodiment of the present invention provides a system that allocates memory for immutable data on a computing device. During operation, the system receives an application to be executed on the computing device. Next, the system allocates a memory region on the computing device to store immutable data for the application. Note that this memory region is smaller than the immutable data for the application. When the system subsequently receives a request to access a block of immutable data for the application, the system allocates space in this memory region for the block, and proceeds to load the block into the memory region. However, if at a later time the space occupied by this first block is needed for another block, the system unloads and discards the first block. If a subsequent operation needs to use information in the first block, the system regenerates the block by transforming raw data associated with the block into a form that can be directly accessed by the application, and then reloads the block into the memory region.

Techniques are disclosed for sharing programmatic modules among isolated virtual machines. A master JVM process loads data from a programmatic module, storing certain elements of that data into its private memory region, and storing other elements of that data into a 'read-only' area of a shareable memory region. The master JVM process copies loaded data from its private memory region into a 'read/write' area of the shareable memory region. Instead of re-loading the data from the programmatic module, other JVM processes map to the read-only area and also copy the loaded data from the read/write area into their own private memory regions. The private memory areas of all of the JVM processes begin at the same virtual memory address, so references between read-only data and copied data are preserved correctly. As a result, multiple JVM processes start up faster, and memory is conserved by avoiding the redundant storage of shareable data.

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Netanya, Israel

Erez Landau