Controlling memory usage in systems having limited physical memory

• US 20050021917A1
• Filed: 08/17/2004
• Published: 01/27/2005
• Est. Priority Date: 05/06/1997
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Fuller, Jason, Mitchell, William H., Mathur, Sharad, Kitowicz, Anthony, Fenwick, Thomas, Ginsberg, Michael
• Granted Patent: US 8,056,081 B2
• Time in Patent Office: Days
• US Class Current: 711/159
• CPC Class Codes: G06F 9/44594 Unloading
• CPC Class Codes: G06F 9/5016 the resource being the memory

Abstract

Described herein is a method of controlling memory usage in a computer system having limited physical memory, wherein one or more application programs execute in conjunction with an operating system. At a first memory usage threshold, the operating system requests at least one of the application programs to limit its use of memory. At a second memory usage threshold that is more critical than the first memory usage threshold, the operating system requests at least one of the application programs to close itself. At a third memory usage threshold that is more critical than the first and second memory usage thresholds, the operating system terminates at least one of the application programs without allowing its further execution.

Claims

1. A method of controlling memory usage in a computer system having limited physical memory, wherein one or more application programs execute in conjunction with an operating system, the method comprising:

setting a plurality of memory thresholds; and

the operating system wielding, at increasingly critical memory thresholds, correspondingly increasing control over the one or more application programs to reduce memory usage.

2. A method as recited in claim 1, wherein wielding increasing operating system control comprises:

at a less critical memory threshold, communicating a request to at least one of the application programs for the at least one of the application programs to limit its use of memory;

at a more critical memory threshold, terminating at least one of the application programs without allowing its further execution.

3. A method as recited in claim 1, wherein wielding increasing operating system control comprises:

prompting a user to select at least one of the application programs; and

then

requesting, by the operating system, that the at least one application program close itself.

4. A method as recited in claim 1, wherein wielding increasing operating system control comprises:

prompting a user to select at least one of the application programs; and

then

terminating it without allowing its further execution.

5. A method as recited in claim 1, wherein wielding increasing operating system control comprises:

at a first memory threshold, requesting at least one of the application programs to limit its use of memory;

at a second memory threshold, requesting at least one of the application programs to close itself; and

at a third memory threshold, terminating at least one of the application programs without allowing its further execution.

6. A method as recited in claim 1, wherein wielding increasing operating system control comprises:

at a first memory threshold, requesting at least one of the application programs to limit its use of memory;

at a second memory threshold, prompting a user to select at least one of the application programs and then requesting it to close itself; and

at a third memory threshold, prompting the user to select at least one of the application programs and then terminating it without allowing its further execution.

7. A method as recited in claim 1, further comprising, at one or more of the memory thresholds, reclaiming unused stack memory.

8. A method as recited in claim 1, further comprising, at one or more of the memory thresholds, discarding read-only memory.

9. A computer-readable storage medium having computer-executable instructions, which, when executed by one or more processors, cause the one or more processors to perform acts consonant with a method of controlling memory usage in a computer system having limited physical memory, wherein one or more application programs execute in conjunction with an operating system, the acts comprising:

setting a plurality of memory thresholds; and

the operating system wielding, at increasingly critical memory thresholds, correspondingly increasing control over the one or more application programs to reduce memory usage.

10. A computer-readable storage medium having instructions for controlling memory usage in a computer system having limited physical memory, wherein one or more application programs execute in conjunction with an operating system, the instructions being executable by the computer system to perform acts comprising:

at a first memory usage threshold, requesting at least one of the application programs to close itself; and

at a second memory usage threshold that is more critical than the first memory usage threshold, terminating at least one of the application programs without allowing its further execution.

11. A computer-readable storage medium as recited in claim 10, the instructions being executable to perform additional acts comprising:

before requesting, prompting a user to select one of the application programs to be closed;

before terminating, prompting the user to select one of the application programs to be terminated.

12. A computer-readable storage medium as recited in claim 10, the instructions being executable to perform additional acts comprising:

before requesting, requiring a user to select one of the application programs to be closed; and

before terminating, requiring the user to select one of the application programs to be terminated.

13. A computer-readable storage medium as recited in claim 10, the instructions being executable to perform an additional step comprising:

at a further memory threshold that is less critical than the first and second memory usage thresholds, requesting at least one of the application programs to limit its use of memory.

14. A computer-readable storage medium as recited in claim 10, the instructions being executable to perform an additional act comprising reclaiming unused stack memory before requesting and before terminating.

15. A computer-readable storage medium as recited in claim 10, the instructions being executable to perform an act step comprising discarding read-only memory before requesting and before terminating.

16. A computer-readable storage medium as recited in claim 10, the instructions being executable to perform additional acts comprising reclaiming unused stack memory and discarding read-only memory before requesting and before terminating.

17. A method of controlling memory usage in a computer system having limited physical memory, wherein one or more application programs execute in conjunction with an operating system, comprising:

at a first memory usage threshold, requesting at least one of the application programs to limit its use of memory;

at a second memory usage threshold that is more critical than the first memory usage threshold, requesting at least one of the application programs to close itself;

at a third memory usage threshold that is more critical than the first and second memory usage thresholds, terminating at least one of the application programs without allowing its further execution; and

reclaiming unused stack memory and discarding read-only memory before requesting at least one of the application programs to close itself and before terminating at least one of the application programs.

18. A method as recited in claim 17, wherein reclaiming and discarding are performed at further memory usage thresholds that are set in relation to the second and third memory usage thresholds.

19. A method as recited in claim 17, wherein reclaiming and discarding are performed at further memory usage thresholds that are set in relation to the first, second, and third memory usage thresholds.

20. A method as recited in claim 17, further comprising the following additional acts:

before requesting, prompting a user to select one of the application programs to be closed; and

before terminating, prompting the user to select one of the application programs to be terminated.

21. A method as recited in claim 17, further comprising the following additional acts:

before requesting, requiring a user to select one of the application programs to be closed; and

before terminating, requiring the user to select one of the application programs to be terminated.

22. A computer-readable storage medium having computer-executable instructions which, when executed by one or more processors, cause the one or more processors to control memory usage in a computer system having limited physical memory, wherein one or more application programs execute in conjunction with an operating system, by causing the one or more processors to perform acts of:

requesting at least one of the application programs to limit its use of memory at a first memory usage threshold;

requesting at least one of the application programs to close itself at a second memory usage threshold that is more critical than the first memory usage threshold;

terminating at least one of the application programs without allowing its further execution at a third memory usage threshold that is more critical than the first and second memory usage thresholds; and

reclaiming unused stack memory and discarding read-only memory before requesting and before terminating.

23. A computer system comprising:

a processor;

an operating system that is executable by the processor and that utilizes the physical memory;

a virtual memory system that includes physical memory but does not include secondary storage; and

one or more application programs that utilize the virtual memory system;

wherein the operating system is configured to perform acts of;

monitoring physical memory usage; and

at increasingly critical physical memory usage thresholds, wielding increasing control over the one or more application programs to reduce physical memory usage.

24. A computer system as recited in claim 23, wherein wielding increasing control comprises:

at a less critical memory threshold, interacting with at least one of the application programs to limit its use of memory; and

at a more critical memory threshold, terminating at least one of the application programs without allowing its further execution.

25. A computer system as recited in claim 23, wherein wielding increasing control comprises prompting a user to select at least one of the applications programs and then requesting it to close itself.

26. A computer system as recited in claim 23, wherein wielding increasing control comprises prompting a user to select at least one of the applications programs and then terminating it without allowing its further execution.

27. A computer system as recited in claim 23, wherein wielding increasing control comprises:

at a first memory threshold, requesting at least one of the application programs to limit its use of memory;

at a second memory threshold, requesting at least one of the application programs to close itself; and

at a third memory threshold, terminating at least one of the application programs without allowing its further execution.

28. A computer system as recited in claim 23, wherein wielding increasing control comprises:

at a first memory threshold, requesting at least one of the application programs to limit its use of memory;

at a second memory threshold, prompting a user to select at least one of the application programs and then requesting it to close itself;

at a third memory threshold, prompting the user to select at least one of the application programs and then terminating it without allowing its further execution.

29. A computer system as recited in claim 23, wherein the operating system is further configured to perform the following additional act of reclaiming unused stack memory at one or more of the memory thresholds.

30. A computer system as recited in claim 23, wherein the operating system is further configured to perform the following additional act of discarding read-only memory at one or more of the memory thresholds.

31. A computer system as recited in claim 23, wherein wielding increasing control comprises:

at a first memory threshold, requesting at least one of the application programs to limit its use of memory;

at a second memory threshold, prompting a user to select at least one of the application programs and then requesting it to close itself;

at a third memory threshold, prompting the user to select at least one of the application programs and then terminating it without allowing its further execution; and

before prompting the user, reclaiming unused stack memory and discarding read-only memory.

32. A method of controlling memory usage in a computer system having limited physical memory, wherein one or more application programs execute in conjunction with an operating system, comprising:

monitoring memory usage; and

when memory usage is high, sending a message from the operating system to at least one of the application programs requesting the application program to minimize its current use of memory.

33. A method as recited in claim 32, further comprising sending the message to the application program when memory usage reaches a defined threshold.

34. A method as recited in claim 32, wherein the application programs have respective message loops, the method further comprising sending the message to the application program through its message loop.

35. A method as recited in claim 32, wherein the application programs have respective message loops, the method further comprising sending the message to a particular application program that was least recently active.

36. A computer-readable storage medium having computer-executable instructions for performing the steps recited in claim 32.

37. A computer-readable storage medium having instructions for controlling memory usage in a computer system having limited physical memory, wherein one or more application programs execute in conjunction with an operating system, the instructions being executable by the computer system to perform acts comprising:

monitoring memory usage;

at a defined memory usage threshold, sending a message from the operating system to at least one of the application programs requesting the application program to reduce its current use of memory.

38. A computer-readable storage medium as recited in claim 37, wherein the application programs have respective message loops, the instructions being executable to perform a further act of sending the message to the application program through its message loop.

39. A computer-readable storage medium as recited in claim 37, wherein the application programs have respective message loops, the instructions being executable to perform a further act of sending the message to a particular application program that was least recently active.

40. An application program that resides in a computer-readable memory for execution by a processor in conjunction with an operating system, the application program having a message loop that receives messages from an operating system, the application program being responsive to a particular message received through its message loop to reduce its current use of memory.