KR20050092639A - Memory management method for java virtual machine in mobile communication terminal - Google Patents

Abstract

The present invention relates to a memory management method of a Java virtual machine in a mobile communication terminal. In the conventional Java virtual machine, since the memory is recovered and left as it is, memory is inefficiently used and memory is allocated without determining whether memory is used. There was a problem that the image is broken due to overlap between. In view of the above problems, the present invention includes the steps of: dividing a Java image memory common area into a predetermined piece of memory in a Java virtual machine; Calculating information of a memory fragment about a memory capacity to allocate when the Java application requests memory allocation; Creating a new node in a connection list and storing information of the calculated memory fragment; Searching for a node storing the allocation information of the memory fragment returned from the connection list and deleting the node when the Java application returns the memory; Copying the memory in use behind the memory area retrieved from the Java application to the retrieved memory area to perform memory compression, dividing the memory common area used for image processing into pieces of memory, and allocating memory; By using to distinguish between the memory area in use and the available memory area, there is an effect that the newly allocated memory area does not invade the memory area being used.

Description

MEMORY MANAGEMENT METHOD FOR JAVA VIRTUAL MACHINE IN MOBILE COMMUNICATION TERMINAL}

The present invention relates to a memory management method of a Java virtual machine in a mobile communication terminal, and more particularly, to a memory management method of a Java virtual machine in a mobile communication terminal that enables efficient use of a memory common area used for image processing without wasting memory. will be.

The Java virtual machine of a conventional mobile communication terminal allocates a predetermined amount of memory to a Java application in a memory common area used for image processing and reclaims the allocated memory. The Java application requests memory allocation from the Java virtual machine to process the image. The Java virtual machine allocates the appropriate level of memory in response to memory allocation requests from Java applications. The Java application uses the allocated memory to process the image, and when the memory is used, requests the Java virtual machine to reclaim the memory. The Java virtual machine reclaims the memory used by Java applications to manage the common areas of memory used for image processing.

1 is an exemplary diagram illustrating a method of managing a memory common area used for image processing by a conventional Java virtual machine.

When a Java application requests memory allocation for image processing, the Java virtual machine allocates as many memory areas as needed from the beginning in the common areas of memory used for image processing.

When the Java application or another Java application requests memory allocation, the Java virtual machine allocates a predetermined memory region following the first allocated memory region and stores the index to the next memory address.

When another Java application requests memory allocation, the Java virtual machine allocates memory as needed, starting with the memory address stored in the index, and changes the index to the next memory address.

When a Java application requests memory reclamation, the Java virtual machine frees up unused areas of memory in the memory common area. The memory common area is fragmented and divided into two memory areas.

When a Java application requests memory allocation, the Java virtual machine attempts to free up as much memory as it needs from the unused memory common area. If there is no more memory area to allocate, the Java virtual machine allocates memory from the beginning of the memory common area. Thus, if the first memory area is already in use, the image may be broken.

However, in the prior art as described above, the Java virtual machine recovers the memory and leaves it as it is, so that the memory is inefficiently used and the memory is allocated without determining whether the memory is used. There is a problem.

Accordingly, the present invention has been made in view of the above problems, and the mobile communication is performed by dividing a memory common area into pieces of memory, allocating memory, and moving the memory area in use to the recovered memory area to compress and manage the memory. The purpose is to provide a memory management method of the Java virtual machine in the terminal.

The present invention for achieving the above object comprises the steps of: dividing a Java image memory common area into a predetermined piece of memory in a Java virtual machine; Calculating information of a memory fragment about a memory capacity to allocate when the Java application requests memory allocation; Creating a new node in a connection list and storing information of the calculated memory fragment; Searching for a node storing the allocation information of the memory fragment returned from the connection list and deleting the node when the Java application returns the memory; And copying the memory in use behind the memory area recovered from the Java application to the recovered memory area to perform memory compression.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

A mobile communication terminal in accordance with the present invention includes a memory including a memory common area used for processing Java images; A Java application that performs a task of processing a specific image, and a control unit that executes a Java virtual machine that allocates a predetermined memory area of the memory common area as a memory for image processing of the Java application and retrieves the used memory. .

The memory divides a predetermined area into memory common areas necessary for processing Java images. The Java virtual machine distributes memory common areas to image processing of Java applications. Java applications use the allocated memory area for image processing.

The Java application finishes processing the image and returns the unnecessary memory area to the Java virtual machine. The Java virtual machine reclaims memory from Java applications and relocates and manages memory areas in use in memory common areas.

2 is an exemplary diagram illustrating a memory common area allocated to a Java image processing by a Java virtual machine according to an exemplary embodiment of the present invention.

The memory common area occupies a predetermined area of memory. The Java virtual machine allocates certain memory areas by distributing memory common areas when a Java application requests memory allocation.

FIG. 3 is a diagram illustrating an example of dividing a memory common area allocated to Java image processing of FIG. 2 into memory fragments of 512 Kbyte units.

The Java virtual machine divides the memory common area into 512-byte pieces of memory. The Java virtual machine allocates memory by grouping pieces of memory to fit the amount of memory required by Java applications.

4 is a diagram illustrating an example of configuring a connection list and node information when the Java virtual machine allocates memory according to an embodiment of the present invention.

The linked list configures nodes to store information about memory areas in use in the memory space area.

The Java virtual machine manages the memory fragment information that is allocated by creating nodes in the linked list whenever memory is allocated in units of memory fragments. A node is added to the connection list each time memory is allocated. The node stores the number of allocated pieces of memory, the start address, and the like.

When the memory is returned, the Java virtual machine deletes the retrieved memory node from the linked list.

5 is an exemplary diagram illustrating an operation of allocating and releasing memory by a Java virtual machine according to an exemplary embodiment of the present invention.

An example of how the Java virtual machine divides the memory common area used for image processing into 512-byte pieces of memory and manages the divided pieces of memory using a linked list is as follows.

The Java virtual machine designates a memory area used for image processing of a Java application as a Java image memory common area, and allocates 409,600 bytes (400 KB) to the Java image memory common area.

The Java virtual machine divides the Java image memory common area into 512-byte pieces of memory. At 409,600 bytes, the Java image memory common area is divided into 800 memory fragments.

When a Java application requests 1200 bytes of memory allocation, the Java virtual machine divides 1200 bytes into 512 bytes to calculate the number of pieces of memory to allocate. Since 1200 bytes require three pieces of memory, the Java virtual machine creates one node in the linked list and stores 3 as the number of pieces of memory in this node and 0x0000 as the starting address of the allocated memory.

When a Java application requests 1600 bytes of memory allocation, the Java virtual machine retrieves the connection list and calculates the starting address of the memory to allocate using the value of the start address stored in the last node and the number of pieces of memory. The Java virtual machine divides 1600 bytes into 512 bytes and calculates the number of memory pieces 4 to be allocated. The Java virtual machine creates and attaches a new node to the last node of the linked list, and stores 0x0600 as the start address value and 4 as the number of memory fragments in the created node.

When the Java application requests the memory allocation of 1700 bytes again, the Java virtual machine calculates the starting address of the memory to be allocated by referring to the information of the last node and calculates the number of memory fragments to be allocated as described above. The Java virtual machine stores 4 in the number of pieces of memory in the newly created node and 0x0E00 in the start address.

When the Java application returns 1600 bytes of memory that was allocated a second time, the Java virtual machine retrieves the node that stores the allocation information of the memory returned from the connection list and deletes the node. The memory area stored by the deleted node remains available.

Suppose that the memory allocation information returned by the Java application is located in the middle node of the linked list. If a Java application returns an intermediate region instead of the beginning and end of the Java image memory space region, the middle region of the Java image memory space region remains available. If the memory capacity of the available space located in the middle area is smaller than the memory capacity requested by the Java application, the Java virtual machine cannot reallocate the memory of the available space located in the middle area to the Java application. Thus, the Java virtual machine performs memory compression that relocates the active memory area of the Java image memory common area to eliminate free space.

When returning the memory area used by the Java application, the Java virtual machine performs memory compression by copying the memory in use behind the memory area recovered from the Java application to the memory area from which the memory area is recovered. The Java virtual machine changes the value of the start address of the node information of the memory area to be copied in the connection list to the value of the start address of the retrieved memory area. For example, if the value of the start address of the retrieved memory area is 0x0600 and the value of the start address of the memory area to be copied is 0x0E00, 0x0E00 is changed to 0x0600.

When there are multiple memory areas to copy, the Java virtual machine calculates the difference between the two start addresses by subtracting the value of the start address of the retrieved memory area from the value of the start address of the memory area to be copied first. The Java virtual machine changes the value of the start address by subtracting the difference between the two start addresses from the value of the start address of each memory area to be copied.

As described in detail above, the present invention divides a memory common area used for image processing into memory fragments and allocates memory, and uses a linked list to classify the memory area being used and the available memory area, thereby providing a newly allocated memory area. It has the effect of not invading the memory area in use.

In addition, when the memory is recovered, the memory is compressed to eliminate empty space, thereby effectively using the memory area without waste.

1 is an exemplary diagram illustrating a method for managing a memory common area used for image processing by a conventional Java virtual machine.

2 is an exemplary view showing a memory common area allocated to Java image processing by a Java virtual machine according to an embodiment of the present invention.

3 is a diagram illustrating an example of dividing a memory common area allocated to Java image processing of FIG. 2 into memory fragments of 512 Kbytes;

4 illustrates an example of configuring a connection list and node information when a Java virtual machine allocates memory according to an embodiment of the present invention.

5 is an exemplary diagram illustrating an operation of allocating and releasing memory by a Java virtual machine according to an exemplary embodiment of the present invention.

Claims (3)

Dividing a Java image memory common area into a predetermined unit of memory in a Java virtual machine; Calculating information of a memory fragment about a memory capacity to allocate when the Java application requests memory allocation; Creating a new node in a connection list and storing information of the calculated memory fragment; Searching for a node storing the allocation information of the memory fragment returned from the connection list and deleting the node when the Java application returns the memory; Copying the memory in use behind the memory area recovered from the Java application to the recovered memory area to perform memory compression. The method of claim 1, wherein the calculating of the memory fragment information comprises: calculating a number of memory fragments by dividing a memory capacity requested by a Java application by a memory fragment; Calculating a start address of a memory to be allocated by adding an address offset obtained by multiplying the number of pieces of memory stored in the last node of the connection list and the capacity of the pieces of memory to the start address of the last node; How memory is managed in a virtual machine. 2. The method of claim 1, wherein the memory compression comprises: copying an in-use memory located behind the recovered memory area to the recovered memory area; Obtaining a difference between two start addresses by subtracting the value of the start address of the retrieved memory area from the value of the start address of the memory area to be copied initially; And changing the value of the start address by subtracting the difference between the two start addresses from the value of the start address of each memory area to be copied.