System, method and computer program product for organizing page caches

• US 6,115,790 A
• Filed: 08/29/1997
• Issued: 09/05/2000
• Est. Priority Date: 08/29/1997
• Status: Expired due to Term

• Current Assignee: Hewlett Packard Enterprise Development LP (Hewlett-Packard Enterprise Company)
• Original Assignee: Silicon Graphics Incorporated (Graphics Properties Holdings, Inc.)
• Inventors: Schimmel, Curt F.
• Primary Examiner(s): Cabeca, John W.
• Assistant Examiner(s): Chow, Christopher S.
• Application Number:
  US08/921,257
• Time in Patent Office: 1,103 Days
• Field of Search: 711/119, 711/130, 711/148, 711/147, 711/206, 711/210
• US Class Current: 711/119
• CPC Class Codes: G06F 12/023 Free address space management
• CPC Class Codes: G06F 12/0813 with a network or matrix configuration
• CPC Class Codes: G06F 9/52 Program synchronisation; Mutual exclusion, e.g. by means of semaphores

Abstract

A system, method and computer program product for distributing page caches among memory objects and, in a DSM system, among memories in the DSM system. The system, method and computer program product provides a separate page cache for each memory object. Each separate page cache associates page frame data structures that represent pages of memory that store a portion of an associated memory object. A separate mutual exclusion mechanism is provided for each page cache for protecting the integrity of the page caches during page cache operations. Page cache operations, such as adding and deleting page frame data structures, checking and updating state information in page frame data objects, and identifying page frame data objects that correspond to particular memory objects or memory object logical offsets, can be performed for different memory objects in parallel.

Claims

1. A method for caching page frame data objects in a computer system, the computer system comprising a plurality of pages of memory for storing pages of memory objects and an operating system for generating a page frame data structure for each page of physical memory and for generating a memory object data structure for each memory object, wherein the operating system employs the page frame data structures for representing the pages of physical memory and wherein the operating system employs the memory object data structures for representing the memory objects, the method comprising the step of:

(1) generating page frame data structures to represent pages of memory;

(2) storing a portion of a first memory object in a first set of pages of memory

(3) generating a first memory object data structure to represent the first memory object;

(4) organizing page frame data structures that represent the first set of pages of memory in a first page cache;

(5) storing a portion of a second memory object in a second set of pages of memory;

(6) generating a second memory object data structure to represent the second memory object; and

(7) organizing page frame data structures that represent the second set of pages of memory in a second page cache.

2. The method according to claim 1, further comprising the step of:

(8) performing a page cache operation on one of the first and second page caches.

3. The method according to claim 2, wherein step (8) comprises the step of:

(a) protecting the integrity of the one of the first and second page caches during the page cache operation.

4. The method according to claim 2, wherein step (8) comprises the step of:

(a) searching the page frame data structures in the one of the first and second page caches for a page frame data structure that stores a particular logical offset value.

5. The method according to claim 4, wherein step (8) further comprises the step of:

(b) checking state information that is stored in the page frame data structure that stores the particular logical offset value.

6. The method according to claim 4, wherein step (8) further comprises the step of:

(b) updating state information that is stored in the page frame data structure that stores the particular logical offset value.

7. The method according to claim 4, wherein step (8) further comprises the step of:

(b) determining a physical address of a page frame that is represented by the page frame data structure that stores the particular logical offset value.

8. The method according to claim 7, wherein step (8) further comprises the step of:

(c) accessing the page frame using the physical address determined from the page frame data structure that stores the particular logical offset value.

9. The method according to claim 2, wherein step (8) comprises the step of:

(a) adding a first page frame data structure to the page cache when a page of the memory object is placed in a page of memory that is represented by the first page frame data structure.

10. The method according to claim 2, wherein step (8) comprises the step of:

(a) removing a first page frame data structure from the page cache when a page of the memory object is removed from the page of memory that is represented by the first page frame data structure.

11. The method according to claim 2, wherein step (8) comprises the steps of:

(a) deleting a first page frame data structure that represents a first page frame from the first page cache when a page of data of the first memory object is moved from the first page frame to a second page frame; and

(b) adding a second page frame data structure that represents the second page frame to the first page cache when the page of data of the first memory object is moved from the first page frame to the second page frame.

12. The method according to claim 1, further comprising the step of:

(8) storing the first page cache and the first memory object data structure proximate to one another, in a distributed shared memory system.

13. The method according to claim 1, further comprising the step of:

(8) storing the first page cache proximate to a processor that first references the first memory object, in a distributed shared memory system.

14. The method according to claim 1, further comprising the step of:

(8) storing the first memory object data structure proximate to a processor that first references the first memory object, in a distributed shared memory system.

15. The method according to claim 1, wherein step (4) comprises the step of:

(a) organizing page frame data structures that represent the first set of pages of memory in a first page cache using a data structure.

16. The method according to claim 1, wherein step (4) comprises the step of:

(a) organizing page frame data structures that represent the first set of pages of memory in a first page cache using a hash table data structure.

17. A method for caching page frame data objects in a computer system, the computer system comprising a plurality of pages of memory for storing pages of memory objects and an operating system for generating a page frame data structure for each page of physical memory and for generating a memory object data structure for each memory object, wherein the operating system employs the page frame data structures for representing the pages of physical memory and wherein the operating system employs the memory object data structures for representing the memory objects, the method comprising the steps of:

(1) organizing page frame data structures that represent pages of memory that store pages of a first memory object in a first page cache;

(2) organizing page frame data structures that represent pages of memory that store pages of a second memory object in a second page cache;

(3) selecting the first page cache for a first page cache operation; and

(4) performing the first page cache operation on the first page cache.

18. The method according to claim 17, wherein step (4) comprises the step of:

(a) protecting the integrity of the first page cache during the first page cache operation.

19. The method according to claim 17, further comprising the step of:

(5) selecting the second page cache for a second page cache operation; and

(6) performing the second page cache operation on the second page cache.

20. The method according to claim 19, wherein step (6) comprises the step of:

(a) performing the second page cache operation on the second page cache while the first page cache operation is being performed on the first page cache.

21. The method according to claim 20, further comprising the steps of:

(7) protecting the integrity of the first page cache during the first page cache operation; and

(8) protecting the integrity of the second page cache during the second page cache operation.

22. The method according to claim 17, wherein step (4) comprises the step of:

(a) searching the page frame data structures in the first page cache for a page frame data structure that stores a particular logical offset value.

23. The method according to claim 22, wherein step (4) further comprises the step of:

(b) checking state information that is stored in the page frame data structure that stores the particular logical offset value.

24. The method according to claim 22, wherein step (4) further comprises the step of:

(b) updating state information that is stored in the page frame data structure that stores the particular logical offset value.

25. The method according to claim 22, wherein step (4) further comprises the step of:

(b) determining a physical address of a page frame that is represented by the page frame data structure that stores the particular logical offset value.

26. The method according to claim 25, wherein step (4) further comprises the step of:

(c) accessing the page frame using the physical address determined from the page frame data structure that stores the particular logical offset value.

27. The method according to claim 17, wherein step (4) comprises the step of:

(a) adding a first page frame data structure to the page cache when a page of the memory object is placed in a page of memory that is represented by the first page frame data structure.

28. The method according to claim 17, wherein step (4) comprises the step of:

(a) removing a first page frame data structure from the page cache when a page of the memory object is removed from the page of memory that is represented by the first page frame data structure.

29. The method according to claim 17, wherein step (4) comprises the steps of:

(a) deleting a first page frame data structure that represents a first page frame from the page cache when a page of data of the first memory object is moved from the first page frame to a second page frame; and

(b) adding a second page frame data structure that represents the second page frame to the page cache when the page of data of the first memory object is migrated from the first page frame to the second page frame.

30. A system for caching page frame data objects in a computer system, the computer system comprising a plurality of pages of memory for storing pages of memory objects and an operating system for generating a page frame data structure for each page of physical memory and for generating a memory object data structure for each memory object, wherein the operating system employs the page frame data structures for representing the pages of physical memory and wherein the operating system employs the memory object data structures for representing the memory objects, the system comprising:

a module that organizes page frame data structures that represent pages of memory that store pages of a first memory object in a first page cache;

a module that organizes page frame data structures that represent pages of memory that store pages of a second memory object in a second page cache;

a module that selects the first page cache for a first page cache operation; and

a module that performs the first page cache operation on the first page cache.

31. The system according to claim 30, further comprising:

a module that selects the second page cache for a second page cache operation; and

a module that performs the second page cache operation on the second page cache.

32. The system according to claim 31, wherein said module that performs the second page cache operation on the second page cache

performs the second page cache operation on the second page cache while the first page cache operation is being performed on the first page cache.

33. The system according to claim 32, further comprising:

a first mutual exclusion mechanism that protects the integrity of the first page cache during the first page cache operation; and

a second mutual exclusion mechanism that protects the integrity of the second page cache during the second page cache operation.

34. The system according to claim 30, further comprising:

a module that deletes a first page frame data structure that represents a first page frame from the page cache, when a page of data of the first memory object is moved from the first page frame to a second page frame; and

a module that adds a second page frame data structure that represents the second page frame to the page caches when the page of data of the first memory object is moved from the first page frame to the second page frame.

35. The system according to claim 30, further comprising:

a module that stores the first page cache, and a first memory object data structure that represents the first memory object, proximate to one another in a portion of memory in a distributed shared memory system.

36. The system according to claim 30, further comprising:

a module that stores the first page cache in a portion of memory in a distributed shared memory system that is proximate to a processor that first references the first memory object.

37. The system according to claim 30, further comprising:

a module that stores a first memory object data structure that represents the first memory object in a portion of memory in a distributed shared memory system that is proximate to a processor that first references the first memory object.

38. A computer program product comprising a computer useable medium having computer program logic stored therein, said computer program logic for enabling a computer to generate a separate page of page frame data structures for each memory object, wherein said computer program logic comprises:

a procedure that enables the computer to organize page frame data structures that represent pages of memory that store pages of a first memory object in a first page cache;

a procedure that enables the computer to organize page frame data structures that represent pages of memory that store pages of a second memory object in a second page cache;

a procedure that enables the computer to select the first page cache for a first page cache operation; and

a procedure that enables the computer to perform the first page cache operation on the first page cache.

39. The computer program product according to claim 38, further comprising:

a procedure that enables the computer to select the second page cache for a second page cache operation; and

a procedure that enables the computer to perform the second page cache operation on the second page cache.

40. The computer program product method according to claim 39, wherein said procedure that enables the computer to perform the second page cache operation on the second page cache

enables the computer to perform the second page cache operation on the second page cache while the first page cache operation is being performed on the first page cache.

41. The computer program product according to claim 40, further comprising:

a procedure that enables the computer to protect the integrity of the first page cache during the first page cache operation with a first mutual exclusion mechanism; and

a procedure that enables the computer to protect the integrity of the second page cache during the second page cache operation with a second mutual exclusion mechanism.

42. The computer program product according to claim 38, further comprising:

a procedure that enables the computer to delete a first page frame data structure that represents a first page frame from the page caches when a page of data of the first memory object is migrated from the first page frame to a second page frame; and

a procedure that enables the computer to add a second page frame data structure that represents the second page frame to the page cache, when the page of data of the first memory object is migrated from the first page frame to the second page frame.

43. The computer program product according to claim 38, further comprising:

a procedure that enables the computer to store the first page cache and a first memory object data structure that represents the first memory object, proximate to one another in a portion of memory in a distributed shared memory system.

44. The computer program product according to claim 38, further comprising:

a procedure that enables the computer to store the first page cache in a portion of memory in a distributed shared memory system that is proximate to a processor that first references the first memory object.

45. The computer program product according to claim 38, further comprising:

a procedure that enables the computer to store a first memory object data structure that represents the first memory object in a portion of memory in a distributed shared memory system that is proximate to a processor that first references the first memory object.