Efficient cache management

• US 8,775,737 B2
• Filed: 12/02/2010
• Issued: 07/08/2014
• Est. Priority Date: 12/02/2010
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Hsieh, Bor-Ming, Rogers, Andrew M.
• Primary Examiner(s): YU, JAE UN
• Application Number:
  US12/958,674
• Publication Number:
  US 20120144092A1
• Time in Patent Office: 1,314 Days
• Field of Search: 711/118, 711/129, 711/170, 711/171
• US Class Current: 711/118
• CPC Class Codes: G06F 12/023 Free address space management
• CPC Class Codes: G06F 12/0871 Allocation or management of cache space
• CPC Class Codes: G06F 2212/1044 Space efficiency improvement
• CPC Class Codes: G06F 2212/2515 being configurable for different purposes, e.g. as cache or non-cache memory
• CPC Class Codes: G06F 2212/601 Reconfiguration of cache memory

Abstract

A method of managing memory of a computing device includes providing a first memory that can be allocated as cache memory or that can be used by a computing device component. A first memory segment can be allocated as cache memory in response to a cache miss. Cache size can be dynamically increased by allocating additional first memory segments as cache memory in response to subsequent cache misses. Cache memory size can be dynamically decreased by reallocating first memory cache segments for use by computing device components. The cache memory can be a cache for a second memory accessible to the computing device. The computing device can be a mobile device. The first memory can be an embedded memory and the second memory can comprise embedded, removable or external memory, or any combination thereof. The maximum size of the cache memory scales with the size of the first memory.

Claims

1. A method of managing memory of a computing device, the method comprising:

providing a first memory in the computing device, wherein;

at least an unused portion of the first memory can be used as a non-cache memory; and

the first memory can be allocated as a cache memory or as a free memory for use by one or more computing device components, the cache memory being part of the unused portion of the first memory;

allocating a first segment of the first memory as a segment of the cache memory in response to a first cache miss; and

dynamically increasing the size of the cache memory within the unused portion of the first memory, by allocating additional segments of the first memory as additional segments of the cache memory in response to subsequent cache misses,

wherein the cache memory appears as unused memory to the one or more computing device components, so that the dynamically increasing the size of the cache memory does not decrease an amount of the first memory available to the one or more computing device components.

2. The method of claim 1, wherein portions of the first memory are allocated as either for use by the one or more computing device components or as segments of the cache memory.

3. The method of claim 1, further comprising dynamically decreasing the size of the cache memory by reallocating a portion of the cache memory for use by the one or more computing device components.

4. The method of claim 1, wherein the computing device is a mobile device.

5. The method of claim 1, wherein the cache memory is a cache memory for a second memory accessible to the computing device.

6. The method of claim 5, wherein the first memory comprises non-removable RAM (random-access memory) and the second memory comprises non-removable flash memory.

7. The method of claim 5, wherein the first memory comprises non-removable memory and the second memory comprises removable memory or external memory.

8. The method of claim 1, wherein the first cache miss or any of the subsequent cache misses results from a second memory read or write request issued by the one or more computing device components.

9. The method of claim 8, wherein a cache user receives the second memory read or write request, the method further comprising the cache user issuing a cache memory read or write request.

10. A computing device, comprising:

a first memory that is dynamically allocable and reallocable as a cache memory within an unused portion of the first memory or for use by one or more computing device components as a non-cache memory; and

a memory manager that;

allocates a first segment of the first memory as a segment of the cache memory in response to a first cache miss; and

dynamically increases the size of the cache memory by allocating additional segments of the first memory as additional segments of the cache memory in response to subsequent cache misses,

wherein the cache memory appears as unused memory to the one or more computing device components, so that dynamically increasing the size of the cache memory by the memory manager does not decrease an amount of the first memory available to the one or more computing device components.

11. The computing device of claim 10, wherein portions of the first memory are allocated as either for use by the one or more computing device components or as segments of the cache memory.

12. The computing device of claim 10, wherein the memory manager dynamically decreases the size of the cache memory by reallocating a portion of the cache memory for use by the one or more computing device components.

13. The computing device of claim 10, wherein the computing device is a mobile device.

14. The computing device of claim 10, wherein the cache memory is a cache memory for a second memory accessible to the computing device.

15. The computing device of claim 14, wherein the first memory comprises non-removable RAM and the second memory comprises non-removable flash memory.

16. The computing device of claim 14, wherein the first memory comprises non-removable memory and the second memory comprises removable memory or external memory.

17. The computing device of claim 10, wherein the first cache miss or any of the subsequent cache misses results from a second memory read or write request issued by the one or more computing device components.

18. The computing device of claim 17, further comprising a cache user that receives the second memory read or write request and issues a cache memory read or write request.

19. One or more computer-readable storage media storing computer-executable instructions for causing a computing device to perform a method, the method comprising:

providing a first memory in the computing device, wherein at least a portion of the first memory can be used as a non-cache memory, and the first memory can be allocated as a cache memory within an unused portion of the first memory or for use by one or more computing device components;

receiving a first second memory read or write request from the one or more computing device components;

allocating a first segment of the first memory as a segment of the cache memory in response to a first cache miss resulting from the first second memory read or write request;

receiving subsequent second memory read or write requests from the one or more computing device components;

dynamically increasing the size of the cache memory by allocating additional segments of the first memory as additional segments of the cache memory in response to subsequent cache misses resulting from the subsequent second memory read or write requests;

receiving a memory allocation request from one of the one or more computing device components; and

allocating a portion of the first memory previously allocated as segments of the cache memory for use by the one of the one or more computing device components,

wherein the cache memory appears as unused memory to the one or more computing device components, so that the dynamically increasing the size of the cache memory does not decrease an amount of the first memory available to the one or more computing device components.