Paging processing system in virtual storage device and paging processing method thereof

• US 6,202,134 B1
• Filed: 11/03/1998
• Issued: 03/13/2001
• Est. Priority Date: 11/07/1997
• Status: Expired due to Fees

• Current Assignee: NEC Corporation
• Original Assignee: NEC Corporation
• Inventors: Shirai, Hiroshi
• Primary Examiner(s): Yoo, Do Hyun
• Assistant Examiner(s): Namazi, Mehdi
• Application Number:
  US09/184,846
• Time in Patent Office: 861 Days
• Field of Search: 711/147, 711/159, 711/170, 711/202-203
• US Class Current: 711/159
• CPC Class Codes: G06F 12/08 in hierarchically structured memory systems, e.g. virtual memory systems

Abstract

A paging processing system in a virtual storage device of a computer composed of a plurality of computers connected directly or over a network including page data reception checking portion for notifying other computer which conducts page-out processing of the number of free physical pages of a physical memory in its own computer, page data reception/transmission portion for conducting processing of receiving page data from other computer and processing of returning received data, page data transmission checking portion for selecting a computer as a page data transmission destination based on the number of free physical pages notified by the page data reception checking portion, page data transmission/reception portion for conducting transmission processing of transmitting, to the other computer selected, page data of a virtual page to be paged out and reception processing when transmitted page data is returned, and page management portion for controlling each of the portion to manage a correspondence relationship between a virtual page and a physical page.

Claims

1. A paging processing system in a virtual storage device of a computer system composed of a plurality of computers connected directly or over a network, comprising:

page data reception checking means for notifying other computer which conducts page-out processing of the number of free physical pages of a physical memory in its own computer;

page data reception/transmission means for conducting processing of receiving page data from other computer and processing of returning received data;

page data transmission checking means for checking a state of vacancy of a physical memory of other computer based on the number of free physical pages notified by said page data reception checking means to select a computer as a page data transmission destination;

page data transmission/reception means for conducting transmission processing of transmitting page data of a virtual page to be paged out to said other computer selected and reception processing when transmitted page data is returned; and

page management means for controlling each of said means to manage a correspondence relationship between a virtual page and a physical page.

2. The paging processing system in a virtual storage device as set forth in claim 1, wherein

said page data transmission checking means inquires of other computer about the number of free physical pages for paging out a physical page in its own computer, and

said page data reception checking means notifies other computer which conducts page-out processing of the number of free physical pages of a physical memory in its own computer according to said inquiry.

3. The paging processing system in a virtual storage device as set forth in claim 1, wherein

said page data reception checking means notifies every other computer of the number of free physical pages of a physical memory in its own computer every fixed time period.

4. The paging processing system in a virtual storage device as set forth in claim 1, wherein

said page data transmission checking means compares states of vacancy of physical memories in other computers based on the numbers of free physical pages notified by said page data reception checking means to select one of the other computers having the largest number of free physical pages as a page data transmission destination computer.

5. The paging processing system in a virtual storage device as set forth in claim 1, wherein

said page data transmission checking means inquires of other computer about the number of free physical pages for paging out a physical page in its own computer,

said page data reception checking means notifies other computer which conducts page-out processing of the number of free physical pages of a physical memory in its own computer according to said inquiry, and

said page data transmission checking means compares states of vacancy of physical memories in other computers based on the numbers of free physical pages notified by said page data reception checking means to select one of the other computers having the largest number of free physical pages as a page data transmission destination computer.

6. The paging processing system in a virtual storage device as set forth in claim 1, wherein

said page data reception checking means notifies every other computer of the number of free physical pages of a physical memory in its own computer every fixed time period, and

said page data transmission checking means compares states of vacancy of physical memories in other computers based on the numbers of free physical pages notified by said page data reception checking means to select one of the other computers having the largest number of free physical pages as a page data transmission destination computer.

7. The paging processing system in a virtual storage device as set forth in claim 1, wherein

said page data reception checking means, when notifying other computer which conducts page-out processing of the number of free physical pages of a physical memory in its own computer, notifies that no free physical page exists if said number of free physical pages is not more than a fixed value.

8. The paging processing system in a virtual storage device as set forth in claim 1, further comprising:

a page table for recording identification information of a paged out virtual page and a page-out destination,

a received page table for recording the identification number of a computer which has transmitted page data by page-out processing, the number of a virtual page of the computer which has transmitted the page data, and the number of a physical page in its own computer which stores the transmitted page data, and

a transmitted page table for recording the identification number of a computer which has received page data and the number of a virtual page whose page data has been transmitted, wherein

in page-out processing, said page data transmission/reception means transmits, to other computer selected, the identification number of its own computer and the number of a virtual page to be paged out as well as page data and records, at said transmitted page table, the identification number of the computer having received the page data and the number of a virtual page whose page data has been transmitted, and

said page management means records, at the page-out destination identification information corresponding to a paged out virtual page in said page table, information indicating that page data is stored in other computer.

9. The paging processing system in a virtual storage device as set forth in claim 8, wherein

in page-in processing, said page data transmission/reception means specifies other computer which stores page data based on page-out destination identification information of said virtual page paged out in said page table and said transmitted page table, makes a request to the specified other computer to return said page data, with the identification number of its own computer and the number of a virtual page corresponding to the page data whose return is requested designated, and transfers said page data returned to a free physical page in its own computer, as well as clearing the identification number of the computer having received the page data and the number of the virtual page whose page data has been transmitted in said transmitted page table.

10. The paging processing system in a virtual storage device as set forth in claim 8, wherein

page said data reception/transmission means of the computer selected to receive the page data stores the transmitted page data in a free physical page of its own computer and records, in said received page table, the identification number of the computer which has transmitted the page data, the virtual page number of the computer which has transmitted the page data and the physical page number of its own computer which stores the page data.

11. The paging processing system in a virtual storage device as set forth in claim 8, wherein

said page data reception/transmission means of the computer requested to return said page data searches said received page table for a combination of the identification number of the computer and the number of a virtual page corresponding to the page data whose return is requested contained in the request for return, transmits data stored at the corresponding physical page number in said received page table to said computer having made a request for return and after the completion of returning, clears the corresponding contents in said received page table.

12. A paging processing method in a virtual storage device of a computer system composed of a plurality of computers connected directly or over a network, comprising the steps of:

notifying other computer which conducts page-out processing of the number of free physical pages of a physical memory in its own computer;

checking out a state of vacancy of a physical memory of other computer based on the notified number of free physical pages to select a computer as a page data transmission destination;

transmitting page data of a virtual page to be paged out to said other computer selected;

managing a correspondence relationship between a virtual page and a physical page; and

notifying every other computer of the number of free physical pages of a physical memory in its own computer every fixed time period.

13. A paging processing method in a virtual storage device of a computer system composed of a plurality of computers connected directly or over a network, comprising the steps of:

notifying other computer which conducts page-out processing of the number of free physical pages of a physical memory in its own computer;

checking out a state of vacancy of a physical memory of other computer based on the notified number of free physical pages and inquiring of other computer about the number of free physical pages for paging out a physical page in its own computer;

notifying other computer which conducts page-out processing of the number of free physical pages of a physical memory in its own computer according to said inquiry;

selecting a computer as a page data transmission destination;

transmitting page data of a virtual page to be paged out to said other computer selected; and

managing a correspondence relationship between a virtual page and a physical page.

14. A paging processing method in a virtual storage device of a computer system composed of a plurality of computers connected directly or over a network, comprising the steps of:

notifying other computer which conducts page-out processing of the number of free physical pages of a physical memory in its own computer;

checking out a state of vacancy of a physical memory of other computer based on the notified number of free physical pages and comparing states of vacancy of physical memories in other computers based on the notified numbers of free physical pages to select one of the other computers having the largest number of free physical pages as a page data transmission destination computers;

transmitting page data of a virtual page to be paged out to said other computer selected; and

managing a correspondence relationship between a virtual page and a physical page.

15. A paging processing method in a virtual storage device of a computer system composed of a plurality of computers connected directly or over a network, comprising the steps of:

notifying other computer which conducts page-out processing of the number of free physical pages of a physical memory in its own computer;

inquiring of other computer about the number of free physical pages for paging out a physical page in its own computer,

notifying other computer which conducts page-out processing of the number of free physical pages of a physical memory in its own computer according to said inquiry, and

comparing states of vacancy of physical memories in other computers based on the notified numbers of free physical pages to select one of the other computers having the largest number of free physical pages as a page data transmission destination computer;

transmitting page data of a virtual page to be paged out to said other computer selected; and

managing a correspondence relationship between a virtual page and a physical page.

16. A paging processing method in a virtual storage device of a computer system composed of a plurality of computers connected directly or over a network, comprising the steps of:

notifying other computer which conducts page-out processing of the number of free physical pages of a physical memory in its own computer;

checking out a state of vacancy of a physical memory of other computer based on the notified number of free physical pages;

notifying every other computer of the number of free physical pages of a physical memory in its own computer every fixed time period;

comparing states of vacancy of physical memories in other computers based on the notified numbers of free physical pages to select one of the other computers having the largest number of free physical pages as a page data transmission destination computers;

transmitting page data of a virtual page to be paged out to said other computer selected; and

managing a correspondence relationship between a virtual page and a physical page.

17. A paging processing method in a virtual storage device of a computer system composed of a plurality of computers connected directly or over a network, comprising the steps of:

notifying other computer which conducts page-out processing of the number of free physical pages of a physical memory in its own computer,

notifying that no free physical page exists if said number of free physical pages is not more than a fixed values;

checking out a state of vacancy of a physical memory of other computer based on the notified number of free physical pages to select a computer as a page data transmission destination;

transmitting page data of a virtual page to be paged out to said other computer selected; and

managing a correspondence relationship between a virtual page and a physical page.

18. A paging processing method in a virtual storage device of a computer system composed of a plurality of computers connected directly or over a network, comprising a page table for recording identification information of a paged out virtual page and a page-out destination, a received page table for recording the identification number of a computer which has transmitted page data by page-out processing, the number of a virtual page of the computer which has transmitted the page data, the number of a physical page in its own computer which stores the transmitted page data, and a transmitted page table for recording the identification number of a computer which has received page data and the number of a virtual page whose page data has been transmitted, the page processing method comprising the steps of:

notifying other computer which conducts page-out processing of the number of free physical pages of a physical memory in its own computer;

checking out a state of vacancy of a physical memory of other computer based on the notified number of free physical pages to select a computer as a page data transmission destination;

transmitting page data of a virtual page to be paged out to said other computer selected; and

managing a correspondence relationship between a virtual page and a physical page;

wherein, in page-out processing, transmitting, to other computer selected, the identification number of its own computer and the number of a virtual page to be paged out as well as page data and records, at said transmitted page table, the identification number of the computer having received the page data and the number of a virtual page whose page data has been transmitted, and

at the page-out destination identification information corresponding to a paged out virtual page in said page table, recording information indicating that page data is stored in other computer.

19. The paging processing method in a virtual storage device as set forth in claim 18, further comprising the step of,

in page-in processing, specifying other computer which stores page data based on page-out destination identification information of said virtual page paged out in said page table and said transmitted page table, makes a request to the specified other computer to return said page data, with the identification number of its own computer and the number of a virtual page corresponding to the page data whose return is requested designated, and transfers said page data returned to a free physical page in its own computer, as well as clearing the identification number of the computer having received the page data and the number of the virtual page whose page data has been transmitted in said transmitted page table.

20. The paging processing method in a virtual storage device as set forth in claim 18, wherein

on the computer selected to receive the page data, the transmitted page data is stored in a free physical page of its own computer, and the identification number of the computer which has transmitted the page data, the virtual page number of the computer which has transmitted the page data and the physical page number of its own computer which stores the page data are recorded in said received page table.

21. The paging processing method in a virtual storage device as set forth in claim 18, wherein

the computer requested to return said page data searches said received page table for a combination of the identification number of the computer contained in the request for return and the number of a virtual page corresponding to the page data whose return is requested, transmits data stored at the corresponding physical page number in said received page table to said computer having made a request for return and after the completion of returning, clears the corresponding contents in said received page table.