Memory allocation scheme

• US 6,941,437 B2
• Filed: 07/18/2002
• Issued: 09/06/2005
• Est. Priority Date: 07/19/2001
• Status: Active Grant

• Current Assignee: Wind River Systems Incorporated (Aptiv PLC)
• Original Assignee: Wind River Systems Incorporated (Aptiv PLC)
• Inventors: Cook, Jeremy, Goloshubin, Alexey
• Primary Examiner(s): Elmore, Stephen C.
• Application Number:
  US10/198,377
• Publication Number:
  US 20030056076A1
• Time in Patent Office: 1,146 Days
• Field of Search: 711/173, 711/6, 711/154, 711/158, 711/170, 718/104
• US Class Current: 711/173
• CPC Class Codes: G06F 12/023 Free address space management
• CPC Class Codes: G06F 12/0284 Multiple user address space allocation, e.g. using different base addresses interprocessor communication G06F15/163
• CPC Class Codes: G06F 9/5016 the resource being the memory
• CPC Class Codes: G06F 9/5022 Mechanisms to release resources

Abstract

A method for managing a memory is provided which comprises the steps of: receiving a request for a memory allocation from a first application, the request comprising a requested memory amount; estimating a total amount of a memory available to the first application; freeing a partition of the memory sufficient for the first application based on the requested memory amount; and allocating the partition to the first application. The memory can be freed in a number of ways, including, by shutting down other applications based upon a priority or priority state scheme, issuing a shut down request to another application, or by allowing the user to select an application to be shut down.

Claims

1. A method for managing a memory, comprising the steps of:

receiving a request for a memory allocation from a first application, the request comprising a requested memory amount;

determining a total amount of a memory available to the first application;

freeing a partition of the memory sufficient for the first application based on the requested memory amount; and

allocating the partition to the first application;

wherein the step of freeing further comprises shutting down a second application.

2. A method for managing a memory, comprising the steps of:

receiving a request for a memory allocation from a first application, the request comprising a requested memory amount;

determining a total amount of a memory available to the first application;

freeing a partition of the memory sufficient for the first application based on the requested memory amount; and

allocating the partition to the first application;

wherein the step of freeing further comprises the steps of attempting to shut down a second application,

determining whether the partition is free,

proceeding to the allocating step if the partition is free, and

generating an error if the partition is not free.

3. A method for managing a memory, comprising the steps of:

receiving a request for a memory allocation from a first application, the request comprising a requested memory amount;

determining a total amount of a memory available to the first application;

freeing a partition of the memory sufficient for the first application based on the requested memory amount; and

allocating the partition to the first application;

wherein the step of freeing further comprises the steps of

attempting to shut down a second application,

determining whether the partition is free,

proceeding to the allocating step if the partition is free, and

issuing a stop command to the first application if the partition is not free.

4. A method for managing a memory, comprising the steps of:

receiving a request for a memory allocation from a first application, the request comprising a requested memory amount;

determining a total amount of a memory available to the first application;

freeing a partition of the memory sufficient for the first application based on the requested memo amount; and

allocating the partition to the first application;

wherein the step of freeing further comprises sending a de-allocation request to a second application.

5. The method of claim 4, wherein the step of freeing further comprises the steps of

determining whether the partition is free,

proceeding to the allocating step if the partition is free, and

generating an error if the partition is not free.

6. The method of claim 4, wherein the step of freeing further comprises the steps of

determining whether the partition is free,

proceeding to the allocating step if the partition is free, and

generating a stop command to the first application if the partition is not free.

7. A method for managing a memory, comprising the steps of:

receiving a request for a memory allocation from a first application, the request comprising a requested memory amount;

determining a total amount of a memory available to the first application;

freeing a partition of the memory sufficient for the first application based on the requested memory amount; and

allocating the partition to the first application;

wherein the memory is organized in a heap; and

wherein the step of freeing a partition of memory further comprises freeing the partition of memory from the heap.

8. The method as recited in claim 7, wherein the heap is of a type used in a Java programming language.

9. A method for managing a memory comprising the steps of:

assigning a priority to each of a plurality of processes;

receiving a request from a first one of the plurality of processes, the request comprising a requested memory amount;

determining a total amount of memory available for allocation;

if the total amount of memory available is less than the requested amount, freeing a partition of the memory equal to at least the requested amount by freeing memory from one or more of the plurality of processes having an assigned priority which is lower than the assigned priority of the first process; and

allocating the partition of the memory to the first process.

10. The method as recited in claim 9, wherein the processes are applications.

11. The method of claim 9, wherein the step of freeing further comprises shutting down one or more of the plurality of processes having an assigned priority lower than the assigned priority of the first process.

12. The method of claim 9, wherein the step of freeing further comprises the steps of

attempting to shut down one or more of the plurality of processes having an assigned priority lower than the assigned priority of the first process,

determining whether the partition is free,

proceeding to the allocating step if the partition is free, and

generating an error if the partition is not free.

13. The method of claim 9, wherein the step of freeing further comprises the steps of

attempting to shut down one or more of the plurality of processes having an assigned priority lower than the assigned priority of the first process,

determining whether the partition is free,

proceeding to the allocating step if the partition is free, and

issuing a stop command to the first application if the partition is not free.

14. The method of claim 9, wherein the step of freeing further comprises sending a de-allocation request to a second process of the plurality of processes.

15. The method of claim 14, wherein the step of freeing further comprises the steps of

determining whether the partition is free,

proceeding to the allocating step if the partition is free, and

generating an error if the partition is not free.

16. The method of claim 14, wherein the step of freeing further comprises the steps of

determining whether the partition is free,

proceeding to the allocating step if the partition is free, and

issuing a stop command to the second process if the partition is not free.

17. The method as recited in claim 9 wherein the memory is organized in a heap;

and wherein the step of freeing a partition of memory further comprises freeing the partition of memory from the heap.

18. The method as recited in claim 17 wherein the heap is of a type used in a Java programming language.

19. The method as recited in claim 9 wherein the requested memory amount is determined by the user.

20. The method as recited in claim 9 wherein the total memory amount is determined by the user.

21. The method of claim 9, wherein the determining step comprises estimating the total amount of memory available for allocation.

22. A method for managing memory comprising the steps of:

(a) assigning a state-priority to each state of a plurality of processes;

(b) receiving a request for a memory allocation from a first process of the plurality of processes, the first process being in a first state and having a first assigned state-priority;

(c) determining a total amount of memory available for allocation;

(d) if the total amount is greater than or equal to the request, allocating a partition of memory to the first process in an amount equal to at least the requested amount; and

(e) if the total amount is less than the request, shutting down one or more of the processes having a current state-priority which is lower than the first assigned state-priority, starting with the process with the lowest current state-priority, so that memory equal to or greater than the request minus the total amount of memory available for allocation is freed, and allocating a partition of memory to the first process in an amount equal to at least the requested amount.

23. The method of claim 22, wherein at least one of the plurality of processes has a plurality of states, and wherein at least two of the plurality of states have different state-assigned priorities.

24. The method of claim 22, wherein step (e) further comprises the steps of:

(e) (1) attempting to shut down the process with the lowest current state-priority,

(e) (2) determining whether a partition of memory associated with the process is free,

(e) (3) proceeding to the allocating step if the partition is free,

(e) (4) if the partition is not free, repeating steps (e) (2) and (e) (3) for a next process of the one or more processes having a next lowest current state-priority; and

(e) (5) generating an error if the partition is not free, and if steps (e)(2) and (e)(3) have been performed for each of the one or more processes.

25. The method of claim 22, wherein step (e) further comprises the steps of:

(e) (1) attempting to shut down the process with the lowest current state-assigned priority,

(e) (2) determining whether a partition of memory associated with the process is free,

(e) (3) proceeding to the allocating step if the partition is free,

(e) (4) if the partition is not free, repeating steps (e)(2) and (e)(3) for a next process of the one or more processes having a next lowest current state-priority; and

(e) (5) issuing a stop command to the first process if the partition is not free, and if steps (e) (2) and (e) (3) have been performed for each of the one or more processes.

26. The method as recited in claim 22 wherein the memory is organized in a heap;

and wherein the step of allocating a partition of memory further comprises allocating the partition of memory from the heap.

27. The method as recited in claim 26 wherein the heap is of a type used in a Java programming language.

28. The method of claim 22, wherein step (c) comprises estimating the total amount of memory available for allocation.

29. A method for managing memory comprising the steps of:

(a) assigning a priority to each of a plurality of processes;

(b) receiving a request for memory from a first process of the plurality of processes, the first process having a first priority;

(c) determining a total amount of memory available for allocation;

(d) if the total amount is greater than or equal to the request, allocating a partition of memory to the first process in an amount equal to at least the requested amount;

(e) if the total amount is less than the request, shutting down one or more of the plurality of processes with a priority lower than the first priority, starting with the process of the plurality of processes having the lowest assigned priority, so that memory equal to or greater than the request minus the total amount of memory available for allocation is freed, and allocating a partition of memory to the first process in an amount equal to at least the requested amount.

30. The method of claim 29, wherein step (e) further comprises the steps of:

(e) (1) attempting to shut down the process with the lowest assigned priority,

(e) (2) determining whether the partition is free,

(e) (3) proceeding to the allocating step if the partition is free,

(e) (4) if the partition is not free, repeating steps (e)(2) and (e)(3) for a next process of the one or more processes having a next lowest priority; and

(e) (5) generating an error if the partition is not free, and if steps (e)(2) and (e)(3) have been performed for each of the one or more processes.

31. The method of claim 29, wherein step (e) further comprises the steps of:

(e) (1) attempting to shut down the process with the lowest assigned priority,

(e) (2) determining whether the partition is free,

(e) (3) proceeding to the allocating step if the partition is free,

(e) (4) if the partition is not free, repeating steps (e) (2) and (e) (3) for a next process of the one or more processes having a next lowest priority; and

(e) (5) issuing a stop command to the first process if the partition is not free, and if steps (e)(2) and (e)(3) have been performed for each of the one or more processes.

32. The method as recited in claim 29 wherein the memory is organized in a heap;

and wherein the step of allocating a partition of memory further comprises allocating the partition of memory from the heap.

33. The method as recited in claim 32 wherein the heap is of a type used in a Java programming language.

34. The method of claim 29, wherein step (c) comprises estimating the total amount of memory available for allocation.

35. A method for managing memory comprising the steps of:

receiving a request for a memory allocation from a requesting process;

determining a total amount of memory available for allocation;

if the total amount is greater than the request, allocating sufficient memory to the requesting process to fulfill the request;

if the total amount is less than the request;

receiving a selection of one or more other processes to shut down from a user,

shutting down the selected processes and freeing any memory associated with the processes,

repeating the steps of selecting and shutting down steps until memory equal to or greater than the request minus the total amount of memory available for allocation is freed; and

allocating sufficient memory to the requesting process to fulfill the request.

36. The method as recited in claim 35 wherein the selection is controlled by the user specifying a set of rules to determine which process to shut down.

37. The method as recited in claim 35 further comprising the step of displaying an indication of the one or other processes to the user.

38. A memory manager comprising a processing device coupled to a memory, the processing device operative to:

(a) receive a request for a memory allocation from a requesting process;

(b) determine a total amount of memory available for allocation;

(c) compare the total amount to the request;

(c)(1) if the total amount is greater than or equal to the request, allocating sufficient memory to the requesting process to fulfill the request;

(c)(2) if the total amount is less than the request, select one or more processes of the plurality of processes to shut down, shut down the selected processes, free any memory associated with the processes, and allocate sufficient memory to the requesting process to fulfill the request.

39. A system comprising:

a plurality of processes;

a memory; and

a memory manager;

a requesting process of the plurality of processes being operative to send a request for a memory allocation to the memory manager, the request having associated therewith a requested amount of memory;

the memory manager operative to receive a request for a memory allocation from a requesting process;

determine a total amount of memory available for allocation;

compare the total amount to the requested amount;

if the total amount is greater than or equal to the request, allocate an amount of memory equal to at least the requested amount to the requesting process;

if the total amount is less than the request (i) select one or more of the plurality of processes to shut down, (ii) request shut down of the selected processes, (iii) free any memory associated with the processes that have shut down;

repeat (i) through (iii) until memory equal to or greater than the request minus the total amount of memory available for allocation is freed; and

allocate an amount of memory equal to at least the requested amount to the requesting process;

the selected one or more of the plurality of processes operative to shut-down when requested by the memory manger and de-allocate memory when shutting down.

40. The system of claim 39 wherein the requested amount is included in the request.

41. A system comprising

a memory manager;

a memory;

a plurality of processes, each process having one or more states, each state having a corresponding assigned state-priority;

a requesting process of the plurality of processes being operative to send a request for a memory allocation to the memory manager, the request having associated therewith a requested amount of memory;

the memory manager operative to receive the request for a memory allocation from a requesting process of the plurality of processes;

determine a total amount of memory available for allocation;

compare the total amount to the requested amount;

if the total amount is greater than or equal to the requested amount, allocate an amount of memory equal to at least the requested amount to the requesting process;

if the total amount is less than the request, select one or more processes to shut down based upon the current assigned state-priorities;

request the shut down of the selected processes;

free any memory associated with the processes that shut down; and

allocate an amount of memory equal to at least the requested amount to the requesting process;

the one or more of the plurality of processes operative to shut-down when requested by the memory manger; and

de-allocate memory when shutting down.

42. The system of claim 41, wherein the requested amount is included in the request.

43. The system as recited in claim 41 wherein the memory manager and each process functions on a plurality of processing units;

and wherein the memory is distributed among the processing units.

44. A computer readable medium, having stored thereon, computer executable process steps operative to control a computer to manage memory, the process steps comprising:

assigning a priority to each of a plurality of processes;

receiving a request from a first one of the plurality of processes, the request comprising a requested memory amount;

determining a total amount of memory available for allocation;

if the total amount of memory available is less than the requested amount, freeing a partition of the memory equal to at least the requested amount by freeing memory from one or more of the plurality of processes having an assigned priority which is lower than the assigned priority of the first process; and

allocating the partition of the memory to the first process.

45. A computer readable medium, having stored thereon, computer executable process steps operative to control a computer to manage memory, the process steps comprising:

assigning a state-priority to each state of a plurality of processes;

receiving a request for a memory allocation from a first process of the plurality of processes, the first process being in a first state and having a first assigned state-priority;

determining a total amount of memory available for allocation;

if the total amount is greater than or equal to the request, allocating a partition of memory to the first process in an amount equal to at least the requested amount;

if the total amount is less than the request, shutting down one or more of the processes having an assigned state-priority which is lower than the first assigned state-priority, starting with the process with the lowest assigned state-priority, so that memory equal or greater to the request minus the total amount is freed;

allocating a partition of memory to the first process in an amount equal to at least the requested amount.

46. A computer readable medium, having stored thereon, computer executable process steps operative to control a computer to manage memory, the process steps comprising:

assigning a priority to each of a plurality of processes;

receiving a request for memory from a first process of the plurality of processes, the first process having a first priority;

determining a total amount of memory available for allocation;

if the total amount is greater than or equal to the request, allocating a partition of memory to the first process in an amount equal to at least the requested amount;

if the total amount is less than the request, shutting down one or more of the plurality of processes with an assigned priority lower than the first priority, starting with the process of the plurality of processes having the lowest assigned priority, so that memory equal or greater to the request minus the total amount is freed; and

allocating a partition of memory to the first process in an amount equal to at least the requested amount.

47. A computer readable medium, having stored thereon, computer executable process steps operative to control a computer to manage memory, the process steps comprising:

receiving a request for a memory allocation from a requesting process;

determining a total amount of memory available for allocation;

if the total amount is greater than the request, allocating sufficient memory to the requesting process to fulfill the request;

if the total amount is less than the request;

selecting one or more other processes to shut down, the selection controlled by a user,

shutting down the selected processes and freeing any memory associated with the processes,

repeating the steps of selecting and shutting down steps until memory equal to or greater than the request minus the total amount of memory available for allocation is freed, and

allocating sufficient memory to the requesting process to fulfill the request.

48. The computer readable medium as recited in claim 47 wherein the selection is controlled by the user by one or more other specifying a set of rules to determine which process to shut down.

49. A method for managing a memory, comprising the steps of:

receiving a request for a memory allocation from a first application, the request comprising a requested memory amount;

determining a total amount of a memory available to the first application;

freeing a partition of the memory sufficient for the first application based on the requested memory amount; and

allocating the partition to the first application;

wherein the step of freeing includes sending a request for de-allocation of memory to a second application, and, in the second application, freeing memory in accordance with a predetermined set of rules for the second application.

50. A system comprising

a memory manager;

a memory;

a plurality of processes, each process having one or more states, each state having a corresponding assigned state-priority;

a requesting process of the plurality of processes being operative to send a request for a memory allocation to the memory manager, the request having associated therewith a requested amount of memory;

the memory manager operative to receive the request for a memory allocation from a requesting process of the plurality of processes;

determine a total amount of memory available for allocation;

compare the total amount to the requested amount;

if the total amount is greater than or equal to the requested amount, allocate an amount of memory equal to at least the requested amount to the requesting process;

if the total amount is less than the request, select one or more processes to request memory de-allocation from based upon the current assigned state-priorities;

request de-allocation of memory from the selected processes;

de-allocate any memory freed by the one or more processes; and

allocate an amount of memory equal to at least the requested amount to the requesting process;

the one or more of the plurality of processes being operative to free memory in accordance with a predetermined set of rules when requested by the memory manager.

51. A method for managing a memory comprising the steps of:

receiving a request from a first one of the plurality of processes, the request comprising a requested memory amount;

estimating a total amount of memory available for allocation;

if the total amount of memory available is less than the requested amount, freeing a partition of the memory equal to at least the requested amount by freeing memory from one or more of the plurality of processes having an assigned priority which is lower than the assigned priority of the first process; and

allocating the partition of the memory to the first process.

52. A method for managing memory comprising the steps of:

(A) receiving a request for a memory allocation from a first process of the plurality of processes, the first process being in a first state and having a first assigned state-priority;

(B) determining a total amount of memory available for allocation;

(C) if the total amount is greater than or equal to the request, allocating a partition of memory to the first process in an amount equal to at least the requested amount; and

(D) if the total amount is less than the request, shutting down one or more of the processes having a current state-priority which is lower than the first assigned state-priority, starting with the process with the lowest current state-priority, so that memory equal or greater to the request minus the total amount is freed, and allocating a partition of memory to the first process in an amount equal to at least the requested amount.

53. A system comprising:

a plurality of processes;

a memory manager;

a requesting process of the plurality of processes being operative to send a request for a memory allocation to the memory manager, the request having associated therewith a requested amount of memory;

the memory manager operative to receive a request for a memory allocation from a requesting process;

determine a total amount of memory available for allocation;

compare the total amount to the requested amount;

if the total amount is greater than or equal to the request, allocate an amount of memory equal to at least the requested amount to the requesting process;

if the total amount is less than the request (i) select one or more of the plurality of processes to shut down, (ii) request shut down of the selected processes, (iii) free any memory associated with the processes that have shut down;

repeat (i) through (iii) until memory equal to or greater than the request minus the total amount of memory available for allocation is freed; and

allocate an amount of memory equal to at least the requested amount to the requesting process;

the selected one or more of the plurality of processes operative to shut-down when requested by the memory manager and de-allocate memory when shutting down.

54. A system comprising

a memory manager;

a plurality of processes, each process having one or more states, each state having a corresponding assigned state-priority;

a requesting process of the plurality of processes being operative to send a request for a memory allocation to the memory manager, the request having associated therewith a requested amount of memory;

the memory manger operative to receive the request for a memory allocation from a requesting process of the plurality of processes;

determine a total amount of memory available for allocation;

compare the total amount to the requested amount;

if the total amount is greater than or equal to the requested amount, allocate an amount of memory equal to at least the requested amount to the requesting process;

if the total amount is less than the request, select one or more processes to shut down based upon the current assigned state-priorities;

request the shut down of the selected processes;

free any memory associated with the processes that shut down; and

allocate an amount of memory equal to at least the requested amount to the requesting process;

the one or more of the plurality of processes operative to shut-down when requested by the memory manager; and

de-allocate memory when shutting down.

55. A Java virtual machine comprising:

a plurality of processes;

a memory manager;

a requesting process of the plurality of processes being operative to send a request for a memory allocation to the memory manager, the request having associated therewith a requested amount of memory;

the memory manager operative to receive a request for a memory allocation from a requesting process;

determine a total amount of memory available for allocation;

compare the total amount to the requested amount;

if the total amount is greater than or equal to the request, allocate an amount of memory equal to at least the requested amount to the requesting process;

if the total amount is less than the request (i) select one or more of the plurality of processes to shut down, (ii) request shut down of the selected processes, (iii) free any memory associated with the processes that have shut down;

repeat (i) through (iii) until memory equal to or greater than the request minus the total amount of memory available for allocation is freed; and

allocate an amount of memory equal to at least the requested amount to the requesting process;

the selected one or more of the plurality of processes operative to shut-down when requested by the memory manager and de-allocate memory when shutting down.

56. A Java virtual machine comprising

a memory manager;

a plurality of processes, each process having one or more states, each state having a corresponding assigned state-priority;

a requesting process of the plurality of processes being operative to send a request for a memory allocation to the memory manager, the request having associated therewith a requested amount of memory;

the memory manager operative to receive the request for a memory allocation from a requesting process of the plurality of processes;

determine a total amount of memory available for allocation;

compare the total amount to the requested amount;

if the total amount is greater than or equal to the requested amount, allocate an amount of memory equal to at least the requested amount to the requesting process;

if the total amount is less than the request, select one or more processes to shut down based upon the current assigned state-priorities;

request the shut down of the selected processes;

free any memory associated with the processes that shut down; and

allocate an amount of memory equal to at least the requested amount to the requesting process;

the one or more of the plurality of processes operative to shut-down when requested by the memory manager; and

de-allocate memory when shutting down.

57. A method for managing a memory, comprising the steps of:

receiving a request for a memory allocation from a first application, the request comprising a requested memory amount;

determining a total amount of a memory available to the first application;

freeing a partition of the memory sufficient for the first application based on the requested memory amount; and

allocating the partition to the first application;

wherein the determining step comprises estimating the total amount of memory available for allocation.