Method and system for managing virtual memory

• US 9,201,807 B2
• Filed: 07/25/2005
• Issued: 12/01/2015
• Est. Priority Date: 07/27/2004
• Status: Active Grant

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: Cabillic, Gilbert
• Primary Examiner(s): Tseng, Cheng-Yuan
• Assistant Examiner(s): Otto, Alan
• Application Number:
  US11/188,551
• Publication Number:
  US 20060026563A1
• Time in Patent Office: 3,781 Days
• US Class Current: 1/1
• CPC Class Codes: G06F 12/0802 Addressing of a memory level in which the access to the desired data or data block requires associative addressing means, e.g. caches
• CPC Class Codes: G06F 12/1081 for peripheral access to main memory, e.g. direct memory access [DMA]
• CPC Class Codes: G06F 2212/6012 of operating mode, e.g. cache mode or local memory mode
• CPC Class Codes: G06F 9/30174 for non-native instruction set, e.g. Javabyte, legacy code
• CPC Class Codes: G06F 9/45504 Abstract machines for programme code execution, e.g. Java virtual machine [JVM], interpreters, emulators
• CPC Class Codes: Y02D 10/00 Energy efficient computing, e.g. low power processors, power management or thermal management

Abstract

Methods, computer-readable media, and systems for virtual memory management using the JAVA programming language are provided. In some illustrative embodiments, a computer-readable medium storing a program that, when executed by a processor, performs a method for virtual memory management is provided. The method includes creating a representation of a page table, wherein each entry of the representation comprises a representation of a page descriptor, changing a field of a representation of a page descriptor in the representation of the page table, and updating a corresponding field in a page descriptor of a system level page table using the contents of the field in the representation of the page descriptor. Some illustrative embodiments provide a computer-readable medium storing a program that, when executed by a processor, performs a method for virtual memory management that includes creating a representation of a segment descriptor, changing a field of the representation of the segment descriptor, and updating a corresponding field in a system level segment descriptor using the contents of the field in the representation of the segment descriptor.

Claims

1. A non-transitory computer-readable medium storing a software program that, when executed by a processor, performs a method for virtual memory management comprising:

creating a representation of a page table for a process by instantiating a page table object using a JAVA programming language class representing a system level page table, wherein each entry of the page table representation comprises a representation of a page descriptor and the JAVA programming language class comprises a JAVA programming language method for updating the system level page table; and

changing a field of a page descriptor representation in the page table representation and a corresponding field in a page descriptor of the system level page table during execution of the process when a virtual page corresponding to the page descriptors is removed from memory and when the virtual page is placed in memory,

wherein the JAVA programming language method is executed to change the corresponding field using contents of the field in the page descriptor representation.

2. The non-transitory computer-readable medium of claim 1, the method further comprising:

creating a representation of a page table directory for the process by instantiating a page table directory object using a JAVA programming language class representing a system level page table directory, wherein each entry of the page table directory representation comprises a representation of a page table descriptor and the JAVA programming language class representing the system level page table directory comprises a JAVA programming language method for updating the system level page table directory;

changing a field of a page table descriptor representation in the page table directory representation and a corresponding field in a page table descriptor of the system level page table directory during execution of the process,

wherein the JAVA programming language method for updating the system level page table directory is executed to change the corresponding field in the page table descriptor of the system level page table directory using contents of the field in the page table descriptor representation.

3. The non-transitory computer-readable medium of claim 1, wherein

the JAVA programming language class comprises a constructor to create the system level page table, and

instantiating the page table object further comprises executing the constructor, wherein the system level page table is created.

4. The non-transitory computer-readable medium of claim 2, wherein

the JAVA programming language class representing the system level page table directory comprises a constructor to create the system level page table directory, and

instantiating the page table directory object further comprises executing the constructor, wherein the system level page table directory is created.

5. A system, comprising:

a processor;

a memory;

a virtual machine configured to execute a JAVA programming language configured to execute on the processor; and

a software program configured to execute on the virtual machine, wherein the software program is configured

to create a representation of a page table for a process by instantiating a page table object using a JAVA programming language class representing a system level page table, wherein each entry of the page table representation comprises a representation of a page descriptor and the JAVA programming language class comprises a JAVA programming language method for updating the system level page table, and

to change a field of a page descriptor representation in the page table representation and a corresponding field in a page descriptor of the system level page table during execution of the process when a virtual page corresponding to the page descriptors is removed from the memory and when the virtual page is placed in the memory, wherein the JAVA programming language method is executed to change the corresponding field using contents of the field in the page descriptor representation.

6. The system of claim 5, wherein the software program is further configured

to create a representation of a page table directory for the process by instantiating a page table directory object using a JAVA programming language class representing a system level page table directory, wherein each entry of the page table directory representation comprises a representation of a page table descriptor and the JAVA programming language class representing the system level page table directory comprises a JAVA programming language method for updating the system level page table directory, and

to change a field of a page table descriptor representation in the page table directory representation and a corresponding field in a page table descriptor of the system level page table directory during execution of the process,

wherein the JAVA programming language method for updating the system level page table directory is executed to change the corresponding field in the page table descriptor of the system level page table directory using contents of the field in the page table descriptor representation.

7. The system of claim 5, wherein

the JAVA programming language class comprises a constructor to create the system level page table, and

instantiating the page table object further comprises executing the constructor, wherein the system level page table is created.

8. The system of claim 6, wherein

the JAVA programming language class representing a system level page table directory comprises a constructor to create the system level page table directory, and

instantiating the page table directory object further comprises executing the constructor, wherein the system level page table directory is created.

9. The system of claim 5, wherein the system comprises a mobile device.

10. A non-transitory computer-readable medium storing a software program that, when executed by a processor, performs a method for virtual memory management comprising:

creating a representation of a segment descriptor by instantiating an object using a JAVA programming language class representing a system level segment descriptor, wherein the JAVA programming language class comprises a JAVA programming language native method for updating the system level segment descriptor;

changing a field of the segment descriptor representation; and

executing the JAVA programming language native method to change a corresponding field in the system level segment descriptor using contents of the field in the segment descriptor representation when the field in the segment descriptor representation is changed.

11. The non-transitory computer-readable medium of claim 10, wherein the JAVA programming language class comprises a constructor to create the system level segment descriptor, and instantiating the object further comprises executing the constructor, wherein the system level segment descriptor is created.

12. A non-transitory computer-readable medium storing an operating system program that, when executed by a processor, performs a method for virtual memory management comprising:

creating, for a process, a page table comprising a plurality of page descriptors by instantiating at least one JAVA programming language class comprising a representation of a page table that corresponds to a system level page table, a representation of a page descriptor that corresponds to a page descriptor in the system level page table, and a native method for updating the system level page table from the page table;

using JAVA programming language operations during execution of the process to update a page descriptor in the page table when a virtual page corresponding to the page descriptor is removed from memory and when the virtual memory is placed in memory; and

invoking the native method to update a corresponding page descriptor in the system level page table from the updated page descriptor when the page descriptor in the page table is updated.

13. The non-transitory computer-readable medium of claim 12, wherein at least one field in a page descriptor in the page table is larger than a corresponding field in the corresponding page descriptor, and wherein the native method copies only relevant bits of the field in the page descriptor in the page table into the corresponding field in the corresponding page descriptor.

14. The non-transitory computer-readable medium of claim 13, wherein a pack instruction is executed to copy the relevant bits of the field to the corresponding field.