# US 2008/0189495 A1 · Method for reestablishing hotness of pages

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- Number: US 2008/0189495 A1
- Document ID: US20080189495A1
- Status: Published application
- Kind: A1
- Application number: 11/670,445
- Filed: 2007-02-02
- Published: 2008-08-07
- Earliest claimed: 2007-02-02
- Inventors: Gerald Francis McBrearty; Shawn Patrick Mullen; Jessica Carol Murillo; Johnny Meng-Han Shieh
- Web page: https://patentgrep.com/patent/US20080189495A1

## CPC

- G06F 12/122: of the least frequently used [LFU] type, e.g. with individual count value
- G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N)

## Abstract

A computer implemented method, an apparatus, and a computer usable program product are provided for reestablishing the hotness, or the retention priority, of a page. When a page is paged out of memory, the page's then-current retention priority is saved. When the page is paged in again later, the retention priority of the page is updated to the retention priority that was saved at or before the time the page was last paged out.

## Claims

### Claim 1

A computer implemented method for reestablishing a retention priority of a page, the computer implemented method comprising:
saving a past retention priority of the page, wherein the past retention priority is the retention priority of the page prior to a time the page is paged out;
performing a page in operation on the page at a later time; and
updating the retention priority of the page to the past retention priority of the page in response to performing the page in operation.

### Claim 2 (depends on 1)

The computer implemented method of claim 1, wherein the saving step further comprises:
making an entry in a page table accessible to a memory manager, wherein the entry comprises an identification of the page and the retention priority of the page at the time the page is paged out.

### Claim 3 (depends on 2)

The computer implemented method of claim 2, wherein the identification of the page comprises:
an address of the page.

### Claim 4 (depends on 1)

The computer implemented method of claim 1, wherein the saving step further comprises:
saving the retention priority of the page within the page using at least one data field within the page designated for saving a retention priority indicator.

### Claim 5 (depends on 1)

The computer implemented method of claim 1 wherein the saving and updating steps are performed for pages in a designated area of a memory.

### Claim 6 (depends on 1)

The computer implemented method of claim 1 wherein the saving and updating steps are performed for pages belonging to a specific application.

### Claim 7 (depends on 6)

The computer implemented method of claim 6 wherein the pages belonging to the specific application are determined by one of a memory manager, and the specific application.

### Claim 8 (depends on 6)

The computer implemented method of claim 6 wherein the specific application is identified by one of an administrator, an attribute of the specific application, and a call to an application programming interface by the specific application.

### Claim 9

A computer usable program product comprising a computer usable medium including computer usable code for reestablishing a retention priority of a page, the computer usable program product comprising:
computer usable code for saving a past retention priority of the page, wherein the past retention priority is the retention priority of the page prior to a time the page is paged out;
computer usable code for performing a page in operation on the page at a later time; and
computer usable code for updating the retention priority of the page to the past retention priority of the page in response to performing the page in operation.

### Claim 10 (depends on 9)

The computer usable program product of claim 9, wherein the computer usable code for saving further comprises:
computer usable code for making an entry in a page table accessible to a memory manager, wherein the entry comprises an identification of the page and the retention priority of the page at the time the page is paged out.

### Claim 11 (depends on 10)

The computer usable program product of claim 10, wherein the identification of the page comprises:
an address of the page.

### Claim 12 (depends on 9)

The computer usable program product of claim 9, wherein the computer usable code for saving further comprises:
computer usable code for saving the retention priority of the page within the page using at least one data field within the page designated for saving a retention priority indicator.

### Claim 13 (depends on 9)

The computer usable program product of claim 9, wherein the computer usable code for saving and the computer usable code for updating are executed for pages in a designated area of a memory.

### Claim 14 (depends on 9)

The computer usable program product of claim 9, wherein the computer usable code for saving and the computer usable code for updating are executed for pages belonging to a specific application.

### Claim 15 (depends on 14)

The computer usable program product of claim 14, wherein the pages belonging to the specific application are determined by one of a memory manager, and the specific application.

### Claim 16 (depends on 14)

The computer usable program product of claim 14, wherein the specific application is identified by one of an administrator, an attribute of the specific application, and a call to an application programming interface by the specific application.

### Claim 17

A data processing system for reestablishing a retention priority of a page, comprising:
a storage device, wherein the storage device stores computer usable program code; and
a processor, wherein the processor executes the computer usable program code, wherein the computer usable program code comprises:
computer usable code for saving a past retention priority of the page, wherein the past retention priority is the retention priority of the page prior to a time the page is paged out;
computer usable code for performing a page in operation on the page at a later time; and
computer usable code for updating the retention priority of the page to the past retention priority of the page in response to performing the page in operation.

### Claim 18 (depends on 17)

The data processing system of claim 17, wherein the computer usable code for saving further comprises:
one of computer usable code for making an entry in a page table accessible to a memory manager, wherein the entry comprises an identification of the page and the retention priority of the page at the time the page is paged out, and wherein the identification of the page comprises an address of the page, and computer usable code for saving the retention priority of the page within the page using at least one data field within the page designated for saving a retention priority indicator.

### Claim 19 (depends on 17)

The data processing system of claim 17, wherein the computer usable code for saving and the computer usable code for updating are executed for pages in a designated area of a memory.

### Claim 20 (depends on 17)

The data processing system of claim 17, wherein the computer usable code for saving and the computer usable code for updating are executed for pages belonging to a specific application, wherein the specific application is identified by one of an administrator, an attribute of the specific application, or a call to an application programming interface by the specific application, and wherein the pages belonging to the specific application are determined by one of a memory manager, and the specific application.