Apparatus, system, and method for maintaining a context stack

• US 8,914,417 B2
• Filed: 01/07/2009
• Issued: 12/16/2014
• Est. Priority Date: 01/07/2009
• Status: Expired due to Fees

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Bryan, Lourie A., Kishi, Gregory T., Shotwell, Kerri R., Swingler, Joseph M.
• Primary Examiner(s): Lewis, Alicia
• Assistant Examiner(s): BROMELL, ALEXANDRIA Y
• Application Number:
  US12/349,975
• Publication Number:
  US 20100174762A1
• Time in Patent Office: 2,169 Days
• Field of Search: 710/56, 707/801, 711/132
• US Class Current: 707/801
• CPC Class Codes: G06F 12/0253 Garbage collection, i.e. reclamation of unreferenced memory
• CPC Class Codes: G06F 2209/5011 Pool
• CPC Class Codes: G06F 2212/702 Conservative garbage collection
• CPC Class Codes: G06F 3/0619 in relation to data integrity, e.g. data losses, bit errors
• CPC Class Codes: G06F 3/0656 Data buffering arrangements
• CPC Class Codes: G06F 3/0665 at area level, e.g. provisioning of virtual or logical volumes
• CPC Class Codes: G06F 3/0689 Disk arrays, e.g. RAID, JBOD
• CPC Class Codes: G06F 9/5016 the resource being the memory
• CPC Class Codes: G06F 9/5033 considering data affinity

Abstract

An apparatus, system, and method are disclosed for maintaining a context stack. A monitor module monitors a stack size after each monitor interval for a stack of a plurality of contexts. Each context defines communications between a process and a data set and comprises a pathway for communicating with the data set and a process identifier. A stack module deallocates a context that satisfies a stack policy from the stack if the stack size is within a buffer threshold of a maximum threshold.

Claims

1. A computer program product comprising a non-transitory storage device storing a computer readable program for maintaining a context stack, wherein the computer readable program when executed on a computer causes the computer to:

monitor a stack size after each monitor interval for a stack of a plurality of existing contexts that are not associated to a process of a plurality of processes, wherein each context is associable and reusable with a plurality of processes and comprises a pathway to a data set when not associated to any process of the plurality of processes, the pathway comprising a logical volume identifier and a logical address for the data set, the context defines communications between the process and the data set through the pathway when associated to the process, and each context is returned to the stack when not associated to the process;

deallocate a context that satisfies a stack policy from the stack if the stack size is within a buffer threshold of a maximum threshold.

2. The computer program product of claim 1, wherein the computer readable program is further configured to cause the computer to deallocate a cleanup number of contexts from the stack if the stack size is within the buffer threshold of the maximum threshold.

3. The computer program product of claim 2, wherein the cleanup number is in the range of fifteen to twenty-five percent of the maximum threshold.

4. The computer program product of claim 1, wherein the context satisfies the stack policy if a retention interval is expired after a creation of the context.

5. The computer program product of claim 4, wherein the retention interval is in the range of one hundred to five hundred seconds.

6. The computer program product of claim 1, wherein the context satisfies the stack policy if the context has a largest memory use of the plurality of contexts.

7. The computer program product of claim 1, wherein the context satisfies the stack policy if the context is the earliest created context of the plurality of contexts.

8. The computer program product of claim 1, wherein the context satisfies the stack policy if the context is a least recently used context of the plurality of contexts.

9. The computer program product of claim 1, wherein the computer readable program is further configured to cause the computer to monitor a plurality of stacks and deallocate a reduction number of contexts from at least one stack if a sum of contexts on the plurality of stacks exceeds a stack threshold.

10. The computer program product of claim 1, wherein the computer readable program is further configured to cause the computer to collect statistics on the stack, the buffer threshold is in the range of five to fifteen percent of the maximum threshold, the monitor interval is in the range of one hundred to two hundred seconds, and the minimum threshold is in the range of twenty-five to two hundred contexts and the maximum threshold is in the of one thousand to five thousand contexts.

11. The computer program product of claim 10, wherein the computer readable program is further configured to cause the computer to monitor the stack size with a stack statistic thread that is inactive for the monitor interval, activates after the monitor interval, determines the stack size, and returns to inactivity.

12. The computer program product of claim 1, wherein the monitor interval m is calculated as m=(100)k/v where k is a constant and v is a volume of transactions for the process.

13. The computer program product of claim 1, wherein the computer readable program is further configured to cause the computer to calculate the maximum threshold t_max for a first stack as

14. The computer program product of claim 1, wherein the computer readable program is further configured to cause the computer to:

establish the maximum threshold of contexts allocated to the stack;

establish a minimum threshold wherein the stack has at least the minimum threshold of contexts; and

establish the buffer threshold.

15. An apparatus to maintain a context stack, the apparatus comprising:

a processor;

the processor comprising a monitor module monitoring a stack size after each monitor interval for a stack of a plurality of existing contexts that are not associated to a process of a plurality of processes, wherein each context is associable and reusable with a plurality of processes and comprises a pathway to a data set when not associated to any process of the plurality of processes, the pathway comprising a logical volume identifier and a logical address for the data set, the context defines communications between the process and the data set through the pathway when associated to the process, and each context is returned to the stack when not associated to the process; and

a stack module deallocating a context that satisfies a stack policy from the stack if the stack size is within a buffer threshold of a maximum threshold.

16. The appratus of claim 15, the stack module further deallocating a cleanup number of contexts from the stack if the stack size is within the buffer threshold of the maximum threshold.

17. The apparatus of claim 15, wherein the context satisfies the stack policy if a retention interval is expired after a creation of the context.

18. The apparatus of claim 15, wherein the context satisfies the stack policy if the context is the earliest created of the plurality of contexts.

19. The apparatus of claim 15, wherein the stack module calculates the maximum threshold t_max for a first stack as

20. A system to maintain a context stack, the system comprising:

a plurality of storage devices storing a data set;

a plurality of existing contexts, each context comprising a pathway to a data set when not associated to a process of a plurality of processes, each context is associable and reusable with a pluality of processes and comprise a pathway to a data set when not associated to any process of plurality of processes, the pathway comprising a logical volume identifier and a logical address for the data set, each context defines communications between the process and the data set through the pathway when associated to the process, and each context is returned to the stack when not associated to the process;

a server in communication with the storage devices and comprising

a stack of contexts;

a monitor module monitoring a stack size for the stack after each monitor interval, the monitor interval in the range of one hundred to two hundred seconds; and

a stack module deallocating a context that satisfies a stack policy from the stack if the stack size is within a buffer threshold of a maximum threshold.

21. The system of claim 20, the server further comprising:

a minimum module establishing the maximum threshold of contexts allocated to the stack;

a maximum module establishing a minimum threshold wherein the stack has at least the minimum threshold of contexts; and

a buffer module establishing the buffer threshold.

22. The system of claim 20, wherein the stack module calculates the maximum threshold t_max for a first stack as

23. A method for deploying computer infrastructure, comprising integrating a computer readable program stored on a tangible storage device into a computing system, wherein the program in combination with the computing system performs the following:

monitor a stack size after each monitor interval for a stack of a plurality of existing contexts that are not associated to a process of a plurality of processes, wherein each context is associable and reuseable with a plurality of processes and comprises a pathway to a data set when not associated to any process of the plurality of processes, the pathway comprising a logical volume identifier and a logical address for the data set, the context defines communications between the process and the data set through the pathway when associated to the process, and each context is returned to the stack when not associated to the process; and

deallocate a cleanup number of contexts satisfying a stack policy from the stack from the stack if the stack size is within a buffer threshold of a maximum threshold, wherein the stack policy is satisfied if a retention interval is expired after a creation of the context else if the context has a largest memory use of the plurality of contexts.

24. The method of claim 23, the program further calculating the maximum threshold t_max for a first stack as