DYNAMIC RE-ALLOCATION OF CACHE BUFFER SLOTS

• US 20110320863A1
• Filed: 06/24/2010
• Published: 12/29/2011
• Est. Priority Date: 06/24/2010
• Status: Abandoned Application

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Berger, Deanna Postles Dunn, Fee, Michael, O'Neill, Arthur J. Jr., Orf, Diana Lynn, Amroladze, Ekaterina M., Sonnelitter, Robert J. III
• Application Number:
  US12/822,407
• Publication Number:
  US 20110320863A1
• Time in Patent Office: Days
• US Class Current: 714/6.1
• CPC Class Codes: G06F 11/0724 in a multiprocessor or a multi-core unit multiprocessors per se G06F15/80
• CPC Class Codes: G06F 11/073 in a memory management context, e.g. virtual memory or cache management memory management G06F12/00; testing of static memory units G11C29/00
• CPC Class Codes: G06F 11/0793 Remedial or corrective actions recovery from an exception in an instruction pipeline G06F9/3861; by retry G06F11/1402; for recovering from a failure of a protocol instance or entity H04L69/40
• CPC Class Codes: G06F 11/1666 where the redundant component is memory or memory area
• CPC Class Codes: G06F 11/20 using active fault-masking, e.g. by switching out faulty elements or by switching in spare elements
• CPC Class Codes: G06F 12/0802 Addressing of a memory level in which the access to the desired data or data block requires associative addressing means, e.g. caches
• CPC Class Codes: G06F 12/126 with special data handling, e.g. priority of data or instructions, handling errors or pinning
• CPC Class Codes: G06F 2212/1032 Reliability improvement, data loss prevention, degraded operation etc

Abstract

Dynamic re-allocation of cache buffer slots includes moving data out of a reserved buffer slot upon detecting an error in the reserved buffer slot, creating a new buffer slot, and storing the data moved out of the reserved buffer slot in the new buffer slot.

Claims

1. A computer program product for dynamic re-allocation of cache buffer slots, comprising a tangible storage medium readable by a processing circuit and storing instructions for execution by the processing circuit for performing a method comprising:

moving data out of a reserved buffer slot upon detecting an error in the reserved buffer slot;

creating a new buffer slot; and

storing the data moved out of the reserved buffer slot in the new buffer slot.

2. The computer program product of claim 1, wherein moving the data out of the reserved buffer slot includes:

placing a protection on an index that stores an address of the reserved buffer slot; and

moving the data into a temporary buffer.

3. The computer program product of claim 1, wherein moving the data out of the reserved buffer slot comprises:

determining a condition of the reserved buffer slot; and

upon determining the condition is correctable, marking the reserved buffer slot as ‘

invalid,’

the condition of ‘

invalid’

permitting the reserved buffer slot to be used for data storage, wherein the method further comprises correcting the data before storing the corrected data in the new buffer slot.

4. The computer program product of claim 1, wherein moving the data out of the reserved buffer slot comprises:

determining a condition of the reserved buffer slot; and

upon determining the condition is uncorrectable, marking the reserved buffer slot as ‘

do not use,’

the condition of ‘

do not use’

preventing the reserved buffer slot from being used for data storage, and marking the data as corrupt when moving the data into the new buffer slot.

5. The computer program product of claim 1, wherein creating the new buffer slot includes:

determining whether the new buffer slot contains data;

upon determining the new buffer slot does not contain data, marking the new buffer slot as input/output reserved.

6. The computer program product of claim 1, wherein creating the new buffer slot includes:

determining whether the new buffer slot contains data;

upon determining the new buffer slot contains data;

revoking ownership of the data in the new buffer slot;

determining whether the data in the new buffer slot has been updated;

if the data in the new buffer slot has been updated, casting out the data in the new buffer slot to a level of cache further away from a central processor than a level of cache in which the new buffer slot is contained;

if the data in the new buffer slot has not been updated, invalidating the new buffer slot;

updating a status of the new buffer slot as input/output reserved.

7. The computer program product of claim 1, wherein storing the data moved out of the reserved buffer slot in the new buffer slot comprises:

removing a protection on an index that stores an address of the reserved buffer slot.

8. A system for dynamic re-allocation of cache buffer slots, the system comprising:

a central processor; and

modules configured for execution on the central processor, the modules comprising;

a cache management module configured to move data out of a reserved buffer slot upon detecting an error in the reserved buffer slot; and

a castout module configured to create a new reserved buffer slot, the new reserved buffer slot configured to receive the data moved out of the reserved buffer slot.

9. The system of claim 8, wherein moving the data out of the reserved buffer slot includes:

placing a protection on an index that stores an address of the reserved buffer slot; and

moving the data into a temporary buffer.

10. The system of claim 8, wherein moving the data out of the reserved buffer slot comprises:

determining a condition of the reserved buffer slot; and

upon determining the condition is correctable, marking the reserved buffer slot as ‘

invalid,’

the condition of ‘

invalid’

permitting the reserved buffer slot to be used for data storage, wherein the method further comprises correcting the data before storing the corrected data in the new buffer slot.

11. The system of claim 8, wherein moving the data out of the reserved buffer slot comprises:

determining a condition of the reserved buffer slot; and

upon determining the condition is uncorrectable, marking the reserved buffer slot as ‘

do not use,’

the condition of ‘

do not use’

preventing the reserved buffer slot from being used for data storage, and marking the data as corrupt when moving the data into the new buffer slot.

12. The system of claim 8, wherein creating the new buffer slot includes:

determining whether the new buffer slot contains data;

upon determining the new buffer slot does not contain data, marking the new buffer slot as input/output reserved.

13. The system of claim 8, wherein creating the new buffer slot includes:

determining whether the new buffer slot contains data;

upon determining the new buffer slot contains data;

revoking ownership of the data in the new buffer slot;

determining whether the data in the new buffer slot has been updated;

if the data in the new buffer slot has been updated, casting out the data in the new buffer slot to a level of cache further away from a central processor than a level of cache in which the new buffer slot is contained;

if the data in the new buffer slot has not been updated, invalidating the new buffer slot;

updating a status of the new buffer slot as input/output reserved.

14. The system of claim 8, wherein storing the data moved out of the reserved buffer slot in the new buffer slot comprises:

removing a protection on an index that stores an address of the reserved buffer slot.

15. A computer-implemented method for dynamic re-allocation of cache buffer slots, the method comprising:

moving data out of a reserved buffer slot upon detecting an error in the reserved buffer slot;

creating a new buffer slot; and

storing the data moved out of the reserved buffer slot in the new buffer slot

16. The computer-implemented method of claim 15, wherein moving the data out of the reserved buffer slot includes:

placing a protection on an index that stores an address of the reserved buffer slot; and

moving the data into a temporary buffer.

17. The computer-implemented method of claim 15, wherein moving the data out of the reserved buffer slot comprises:

determining a condition of the reserved buffer slot; and

upon determining the condition is correctable, marking the reserved buffer slot as ‘

invalid,’

the condition of ‘

invalid’

permitting the reserved buffer slot to be used for data storage, wherein the method further comprises correcting the data before storing the corrected data in the new buffer slot.

18. The computer-implemented method of claim 15, wherein moving the data out of the reserved buffer slot comprises:

determining a condition of the reserved buffer slot; and

upon determining the condition is uncorrectable, marking the reserved buffer slot as ‘

do not use,’

the condition of ‘

do not use’

preventing the reserved buffer slot from being used for data storage, and marking the data as corrupt when moving the data into the new buffer slot.

19. The computer-implemented method of claim 15, wherein creating the new buffer slot includes:

determining whether the new buffer slot contains data;

upon determining the new buffer slot does not contain data, marking the new buffer slot as input/output reserved.

20. The computer-implemented method of claim 15, wherein creating the new buffer slot includes:

determining whether the new buffer slot contains data;

upon determining the new buffer slot contains data;

revoking ownership of the data in the new buffer slot;

determining whether the data in the new buffer slot has been updated;

if the data in the new buffer slot has been updated, casting out the data in the new buffer slot to a level of cache further away from a central processor than a level of cache in which the new buffer slot is contained;

if the data in the new buffer slot has not been updated, invalidating the new buffer slot;

updating a status of the new buffer slot as input/output reserved.