METHOD AND APPARATUS FOR DYNAMICALLY SHARING MEMORY IN A MULTIPROCESSOR SYSTEM

• US 20020010844A1
• Filed: 06/10/1998
• Published: 01/24/2002
• Est. Priority Date: 06/10/1998
• Status: Active Grant

• Current Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Original Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Inventors: NOEL, KAREN L., JORDAN, GREGORY H., HARTER, PAUL K. Jr., BENSON, THOMAS
• Granted Patent: US 6,381,682 B2
• Time in Patent Office: Days
• US Class Current: 711/153
• CPC Class Codes: G06F 2209/505 Clust
• CPC Class Codes: G06F 9/5077 Logical partitioning of resources; Management or configuration of virtualized resources specific details on emulation or internal functioning of virtual machines G06F9/455

Abstract

Multiple instances of operating systems execute cooperatively in a single multiprocessor computer wherein all processors and resources are electrically connected together. The single physical machine with multiple physical processors and resources is subdivided by software into multiple partitions, each with the ability to run a distinct copy, or instance, of an operating system. At different times, different operating system instances may be loaded on a given partition. Resources, such as CPUs and memory, can be dynamically assigned to different partitions and used by instances of operating systems running within the machine by modifying the configuration. The partitions themselves can also be changed without rebooting the system by modifying the configuration tree. A grouping of partitions, a community, shares memory. Memory may be private to a particular partition or may be shared by partitions within a community. When a community is formed the creating instance reads a configuration tree and builds management structures for the shared memory owned by the community. A single system may have one or more communities, each with their own representation within the configuration tree.

Claims

1. A computer system having a plurality of system resources including processors, memory and I/O circuitry, the computer system comprising:

an interconnection mechanism for electrically interconnecting the processors, memory and I/O circuitry so that each processor has electrical access to all of the memory and at least some of the I/O circuitry;

a software mechanism for dividing the system resources into a plurality of partitions; and

at least one group of partitions forming a community which shares memory.

2. A computer system according to claim 1 wherein at least some of the memory is exclusively assigned to one of the partitions.

3. A computer system according to claim 1 wherein a segment of the shared memory forms a database for the community'"'"'s shared memory.

4. A computer system according to claim 3 wherein the shared memory database indicates whether an operating system instance associated with a partition within the community is active.

5. A computer system according to claim 4 wherein each instance within a community maps to the shared memory database.

6. A computer system according to claim 5 wherein each instance examines the shared memory database as it maps to the database to determine whether other instances are active and, if other instances are active, joins the community.

7. A computer system according to claim 5 wherein each instance examines the shared memory database as it maps to the database to determine whether other instances are active and, if no other instances are active, creates the community.

8. A computer system according to claim 7 wherein an instance configures the shared memory database as it creates the community.

9. A computer system according to claim 6 wherein access to the shared memory database region is synchronized through use of locks which block access to the database by one instance while another instance is accessing the region.

10. A computer system according to claim 9 wherein each partition comprises a console program which controls the processors in a partition and wherein the computer system further comprises a mechanism for sending configuration information from a master console program to each of the other console programs.

11. A method for constructing a computer system having a plurality of system resources including processors, memory and I/O circuitry, the method comprising the steps of:

(a) electrically interconnecting the processors, memory and I/O circuitry so that each processor has electrical access to all of the memory and at least some of the I/O circuitry;

(b) dividing the system resources into a plurality of partitions; and

(c) forming a community of partitions by sharing memory among a group of partitions.

12. A method according to claim 11 wherein step (b) comprises the step of:

(b1) assigning at least some of the memory to each of the partitions.

13. A method according to claim 11 wherein step (c) comprises the step of:

(c1) forming a shared memory database for the community within the shared memory.

14. A method according to claim 13 wherein step (c1) comprises the step of:

(c1a) including within the shared memory database an indication of whether an operating system instance associated with the community is active.

15. A method according to claim 13 further comprising the step of:

(d) each instance mapping to the shared memory database as it joins a community.

16. A method according to claim 14 further comprising the step of:

(e) each instance examining the shared memory database to determine whether other instances are active and joining the community if other instances are active.

17. A method according to claim 16 wherein step (e) comprises the step of:

(e1) creating the community if no other instance is active.

18. A method according to claim 17 wherein step (e) comprises the step of:

(e2) reconfiguring the shared memory database.

19. A method according to claim 16 wherein step (e) comprises the step of:

(e3) locking the shared memory database to block access to the database by another instance as an instance examines the shared memory database.

20. A computer program product for constructing a computer system having a plurality of system resources including processors, memory and I/O circuitry and hardware for electrically interconnecting the processors, memory and I/O circuitry so that each processor has electrical access to all of the memory and at least some of the I/O circuitry, the computer program product comprising a computer usable medium having computer readable program code thereon including:

(a) program code for dividing the system resources into a plurality of partitions; and

(b) program code for forming a community of partitions which shares memory.

21. A computer program product according to claim 20 wherein the program code for dividing the system resources into a plurality of partitions assigns at least some of the memory exclusively to one of the partitions.

22. A computer program product according to claim 21 wherein the program code for dividing the system resources into a plurality of partitions comprises program code for forming a database for the community'"'"'s shared memory.

23. A computer program product according to claim 22 wherein the program code for forming a database for the community'"'"'s shared memory comprises program code for indicating whether an operating system instances associated with a partition within the community is active.

24. A computer program product according to claim 23 wherein the computer program product for constructing a computer system having a plurality of system resources further comprises program code for mapping each operating system instance within a community to the shared memory database.

25. A computer program product according to claim 26 further comprising program code for each instance examining the shared memory database as the instance maps to the database, determining whether other instances are active, and joining the community if other instances are active, or creating the community if no other instances are active.