JPH0212348A - Page swapping device - Google Patents

Abstract

PURPOSE:To decrease the input/output frequency to a secondary medium and to optimize the system performance by performing the page swap-out/swap-in actions for a real memory in consideration of the dynamic characteristics of each program which runs on a system. CONSTITUTION:A page table change control means 1 is prepared together with a real memory swap-in value deciding means 2, a real memory swap-in means 3, a real memory swap-out value deciding means 4, and a real memory swap-out means 5. When the swap-out/swap-in actions of a virtual computer are carried out, the swap-out value is decided based on the size of a program group under running and the size of a real memory. Then the contents of a swapped-out real memory are swapped in. Thus the input/output frequency is decreased to a secondary medium and the system performance can be optimized.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention is applied to a virtual computer. In particular, the present invention relates to page swap control means when real memory is overloaded.

〔overview〕

The present invention provides a means for executing swap-out and swap-in of a virtual machine, which determines the swap-out amount based on the size of a running program group and the size of real memory, and swaps out the contents of the swapped-out real memory. By doing so, it is possible to reduce the number of inputs and outputs to the secondary medium and optimize system performance.

[Conventional technology]

Conventional page swap control means cannot take into account the size of a group of programs running on a computer or the size of real memory, etc., and when swapping in or out real memory, the amount is unique. It was decided.

[Problem that the invention seeks to solve]

In the conventional example, the dynamic characteristics of a program group running on a computer cannot be taken into account, and system performance cannot be optimized.

The present invention aims to eliminate such drawbacks, and aims to provide a page swap device that performs page swap out and page swap in of real memory in consideration of the dynamic characteristics of each program running on a computer. do.

[Means for solving problems]

The present invention provides a page swapping device that is connected to a computer having real memory and virtual memory and that includes a page table that associates pages of the real memory with pages of the virtual memory, in which a missing page is sent to a program in one of the computers. A page table change control means that registers the occurrence status for each entry in the page table when a fault occurs, and an implementation that calculates the number of entries in which the occurrence of a missing page fault is registered and uses this number of entries as the page swap amount. A memory swap amount determining means, a real memory swap out means for swapping out a number of pages equivalent to this page swap amount from other programs, and a swapping of the number of pages of other programs swapped out by the above real memory swap out means. The invention is characterized by comprising a means for inputting.

[Effect]

If real memory becomes overloaded while the computer is running, the contents of real memory used by other programs are swapped onto a secondary storage medium in order to provide real memory to the program that encountered the overload. When swapping out the memory, determine the swap-out amount and write out the real memory on the secondary medium. It also determines the swap-in amount when swapping in the real memory that was swapped out to the secondary medium of the program that encountered an overload from the secondary medium, and swaps the contents of real memory from the secondary medium. In.

On the other hand, the page table is controlled by determining whether or not the missing page fault occurs in a continuous space on the page table when a missing page fault occurs due to real memory overload.

〔Example〕

Hereinafter, one embodiment of the present invention will be described based on the drawings.

As shown in FIG. 1, this embodiment includes a page table change control means 1, a real memory swap-in amount determining means 2, a real memory swap-in means 3, a real memory swap-out amount determining means 4, and a real memory It consists of a swap-out means 5. Here, page table change control means 1
As shown in FIG. 2, it consists of a current page table pointer area 11 and a page table area 12 corresponding to each program.

That is, this embodiment is connected to a computer having real memory and virtual memory, and has a page table area that associates pages of this real memory with pages of this virtual memory.
12, when a missing page fault occurs in one of the programs of the above computer, the page table area 1
The page table change control means 1 registers the occurrence status for each entry in page 2, and the number of en) U in which the occurrence of the missing page fault is registered is calculated, and the actual memory swap amount is calculated using the number of en) U as the page swap amount. A determining means 4, a real memory swap out means 5 for swapping out the number of pages equivalent to this page swap amount from other programs, and a real memory swap out means 5 for swapping in the number of pages of other programs swapped out by the real memory swap out means Mk5. A real memory swap-in amount determining means 2 and a real memory swap-in means 3 are provided.

Next, a swap operation in virtual memory control of this embodiment will be explained.

When the real memory is overloaded and a missing page fault occurs while the program is running, control passes to the page table change control means 1, and checks whether the missing page faults are continuous on the page table. This is noted on the page table. Subsequently, the control is transferred to the real memory swap-out amount determining means 4, which determines the number of pages in which missing page faults occur continuously on the page table, sets it as a specific page swap amount, and real memory swap-out means 4. 5
The real memory used by other programs in the system is output to the secondary medium by that amount. Next, the real memory swap-in amount determining means 2 determines the number of pages in which missing page faults occur continuously on the page table area 12 and determines the actual real memory swap-in amount. Swap in real memory for the applicable program.

FIG. 2 shows a means for finding consecutive pages on the page table area 12. When a missing page fault occurs, the page table change control means 1 checks whether the current page table pointer points to the entry immediately before the entry in the page table area 12 where the missing page fault occurred, and indicates the previous entry. If so, turn on the consecutive bit on the previous page table entry indicating that the next page was continuously swapped in due to a Mitsujig page fault, and
The value of the current page table pointer in the current page table area 11 is set to indicate the entry in which the missing page fault has occurred this time. For example, in FIG. 2, if page table entry "4" is the entry in which the missing page fault has occurred, the consecutive bits of page table entry "3" are turned on. If the current page table pointer does not point to the immediately previous page table entry when a missing page fault occurs, nothing is done.

By controlling in this way by the page table change control means 1, the real memory swap-in amount determining means 2 and the real memory swap-out amount determining means 4 each count the entries on the page table when a missing page fault occurs. Consecutive entries are checked one after another until the consecutive bit is turned off, the number of entries is counted, and the count value is used as the swap-out amount or swap-in amount of real memory.

〔Effect of the invention〕

As explained above, the present invention performs page swap-out and page swap-in of real memory taking into account the dynamic characteristics of each program running on the system, thereby reducing the number of inputs and outputs to the secondary medium and This has the effect of optimizing performance.

[Brief explanation of the drawing]

FIG. 1 is a block configuration diagram showing the configuration of an embodiment of the present invention. FIG. 2 is an explanatory diagram showing the operation of the page table change control means shown in FIG. 1. DESCRIPTION OF SYMBOLS 1... Page table change control means, 2... Real memory swap-in amount determining means, 3... Real memory swap-in means, 4... Real memory swap-out amount determining means, 5... Real memory Swap-out means, 11... Current page table area, 12... Page table area.

Claims (1)

[Scope of Claims] 1. A page swap device coupled to a computer having real memory and virtual memory and equipped with a page table that associates pages of this real memory with pages of this virtual memory, A page table change control means (1) that registers the occurrence state for each entry in the page table when a missing page fault occurs in a program, and calculates the number of entries in which the occurrence of a missing page fault is registered, a real memory swap amount determining means (4) that takes a number as a page swap amount; a real memory swap out means (5) that swaps out a number of pages equivalent to this page swap amount from another program; means to swap in the number of pages of other programs that were swapped out by means (
2, 3) A page swap device comprising: