JP3083533B2 - Virtual address space management processing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Summary] Regarding a virtual address space management processing method that can dynamically set the opening size of a virtual address space, an unused segment table is not created, and real page resources are allocated. For the purpose of effective use, when creating a virtual address space, create a segment table corresponding to the minimum space size and create a virtual address space.
A region opening processing unit for re-creating a segment table according to the used region size and re-establishing the virtual address space is provided, and a virtual address space is dynamically established according to the used region size.

[Industrial applications]

TECHNICAL FIELD The present invention relates to a virtual address space management processing method that can dynamically set an opening size of a virtual address space.

In recent years, as the size of programs has increased, logical address expansion functions have been supported, and the size of the virtual address space of the system has been dramatically expanded. In addition, the number of operation spaces is increasing due to an increase in workstation terminals and the like. As a result, the actual memory required for the segment table used for the address translation is increasing.

However, in a conventional computer, a real page for a segment table needs to be allocated from a limited real memory resource of, for example, 16 MB or less. Therefore, in order to promote the expansion of logical addresses and the number of spaces, there is a need for a technology that effectively uses limited real memory resources of 16 MB or less.

[Conventional technology]

 FIG. 4 shows an example of the prior art.

In a computer system adopting virtual storage control, correspondence between a logical address and a real address is established by a segment table and a page table.

In such a computer system, the opening size of the virtual address space has conventionally been a fixed value depending on the system. This value is the maximum value of the logical address of the system.

The size of the virtual address space is determined by the size of the segment table. In the space generation process, a segment table is created with the maximum value of the logical space (virtual address space), and the segment table of the region portion is reset every time a region called a region is allocated to a job or the like. The unused and pre-opening regions are set to the segment invalid state.

FIG. 4 shows an outline of processing from generation to erasure of a conventional virtual address space.

The space generation processing unit 20 creates a segment table,
Open a virtual address space. The size of the segment table is initialized according to the maximum value of the logical space of the system. In particular, the region is initialized as an invalid state.

The region opening processing unit 21 initializes a segment table of a region portion (a basic region and an extended region).

The region closing processing unit 22 returns the segment table of the region to an invalid state. Region opening processing section 21
The processing of the region closing processing unit 22 is performed for each execution unit in the computer system such as a job step.

The space end processing unit 23 returns all the segment tables and closes the space.

The space generation processing unit 20 operates when a subsystem is started by a START command or when a terminal logs on, and the space end processing unit 23 operates when a STOP command is input or a terminal logs off. However, for the initiator space and the like, space generation processing is performed when the system is started, and the space is deleted when the system is stopped.

[Problems to be solved by the invention]

In general, even in the case of a small / medium-sized computer system, even if the logical address extension function is introduced, few jobs use the extended region up to the maximum value of the system logical address (for example, 128 MB, 256 MB or 2 GB).

Therefore, if a segment table is created for all the generated spaces up to the maximum value of the logical space of the system, the following problem occurs.

(1) Unnecessary real memory is used for the segment table, and available real memory resources are reduced.

(2) The setting processing of the segment table for the unused area is required, and the processing performance is reduced by that much.

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems, enables the setting of a virtual address space opening size dynamically, prevents the creation of an unused segment table, and enables effective use of real page resources. It is intended to be.

[Means for solving the problem]

 FIG. 1 is a diagram illustrating the principle of the present invention.

In FIG. 1, reference numeral 10 denotes a data processing device including a CPU and a memory, reference numeral 11 denotes a space generation processing unit that generates a virtual address space, reference numeral 12 denotes a region opening processing unit that opens a region used by a user program or the like, and reference numeral 13 denotes a region. , A space end processing unit 14 for erasing the virtual address space, and 15 a segment table used for address conversion.

When generating a virtual address space, the space generation processing unit 11
Segment table 15 corresponding to minimum space size
(A) is created, and processing for opening a virtual address space is performed. That is, the segment table 15 (a) of only the common area part (basic part) of the basic area and the extended area is created and initialized.

When opening a region, the region opening processing unit 12
Segment table 15 according to used region size
(B) is recreated, and the virtual address space is reopened.
That is, the size of the logical space is selected according to the size of the necessary extended region, and the segment table 15 is selected.
(B) is reinitialized. Here, the segment table 15 (b) of the basic region and the extended region portion
Is also initialized.

The region closing processing unit 13 recreates the segment table 15 (b) composed of the basic part and the extended part into the segment table 15 (c) of only the basic part, and returns the virtual address space to the minimum space size. Reopen. That is, the segment table 15 (c) is reinitialized to the same state as immediately after the space generation processing. If there is no next job step or the like, the re-establishment of this space may be omitted.

The space end processing unit 14 returns the real memory for the segment table 15 (d) and closes the virtual address space.

[Action]

In the present invention, there is provided a means for selecting the size of the virtual address space for each space and creating the segment table 15 at the time of opening a region. That is, the virtual address space is dynamically established according to the used region size. As a result, it is not necessary to create an unnecessary segment table.

〔Example〕

FIG. 2 is a configuration diagram of a virtual address space for explaining one embodiment of the present invention, and FIG. 3 shows a processing flow of a region opening processing unit according to one embodiment of the present invention.

In the following example, it is assumed that the size of one segment is 64 KB. Segment table 15 has a maximum of 4 pages (16384B)
Since the size of one entry is 4B, the maximum size of the virtual address space is 256 MB. Note that the internal configuration of the segment table 15 is well known and will not be described.

As shown in Fig. 2 (a), the virtual address space is 16M
It consists of a basic area up to B and an extended area of 16 MB or more.

The virtual address space has a configuration in which the extended region portion is located at the highest level so that the established size can be determined for each virtual address space based on the opened size of the extended region. With this arrangement, the required size of the virtual address space can be determined from the last address of the extended region.

Due to the difference in the size of each space, the size of the segment table 15 also differs as shown in FIG. The hardware address translation mechanism can handle segment tables 15 of different sizes, because the segment table length of each space is set in the first control register (CR1) when the space is switched.

Opening of the virtual address space is performed not only at the time of space generation processing, but also at the time of opening and closing a region. In addition, the opening size of the space is dynamically determined according to the opening size of the region. Note that opening a space means obtaining a segment table area and creating a segment table.

As a result, up to 64 MB of virtual address space can be handled with a segment table 15 of 4096 B size, up to 128 MB of virtual address space can be handled with a segment table 15 of 8192 B size, and up to 256 MB of virtual address space. , 16384B in size.

The space generation processing unit 11 shown in FIG. 1 initializes the segment table 15 with the space size (64 MB) of only the common area between the basic area and the extended area. Note that the basic region and part of the extended region are initialized in an invalid state. In the first control register, a segment length of “3F” is set in hexadecimal.

The region opening processing unit 12 shown in FIG. 1 performs a process as shown in FIG. Hereinafter, description will be made in accordance with the processing shown in FIG.

First, the final address is obtained from the requested extended region size.

The required virtual address space size can be determined from the obtained final address. Therefore, the optimal space size is 6
It determines whether it is 4 MB or less, 128 MB or less, or larger than 128 MB. If the size is 64 MB or less, the process shifts to a process. If the size is 128 MB or less, the process shifts to a process. If the size is larger than 128 MB to 256 MB, the process shifts to a process.

When the space size is larger than 64 MB and smaller than 128 MB, the segment table memory for two pages is acquired, replaced with the segment table at the time of opening the space, and the 128 MB segment table is reinitialized. First
Set "7F" for the segment length of the control register.

When the space size is larger than 128 MB and up to 256 MB, the segment table memory for four pages is acquired, replaced with the segment table at the time of opening the space, and the segment table for 256 MB is reinitialized. First
Set "FF" to the segment length of the control register.

Set the segment table for the region. More specifically, a page table for the region in the basic area and the extended area is acquired, and the page table in that part is initialized to a page invalid state. Then, the entry of the segment table in the region portion is validated.

Although the above embodiment is an example in which the segment size is 64 KB, the present invention can be similarly implemented when the segment size is 1 MB. In this case, for example, as shown in FIG.
The following two types are available from 1GB to 2GB, and either space size is dynamically selected. 1GB virtual address space
In the following cases, the required segment table size is 4096
B, and when the virtual address space is larger, the required segment table size is 8192B.

〔The invention's effect〕

As described above, according to the present invention, the size of each space can be set according to the opening size of the extended region, so that the system can be operated with the minimum necessary number of actual pages for the segment table. Therefore, for example, 16
It can effectively use limited real page resources of less than MB, which greatly contributes to reducing the real memory load of the system and increasing the number of spaces. Further, since the segment table of the unused area is not created, the processing performance related to the setting of the segment table in the space generation process and the region opening process is improved.

[Brief description of the drawings]

FIG. 1 is a diagram for explaining the principle of the present invention, FIG. 2 is a configuration diagram of a virtual address space for explaining an embodiment of the present invention, and FIG. Processing flow, FIG. 4 shows an example of the prior art. In the figure, 10 is a data processing device, 11 is a space generation processing unit, 12 is a region opening processing unit, 13 is a region closing processing unit, 14 is a space processing end unit, and 15 is a segment table.

Claims (1)

(57) [Claims] In a virtual address space management processing method in a computer system which manages a virtual address space by a segment table (15), when a virtual address space is generated, a segment table corresponding to a minimum space size is created, and a virtual address space is created. A space generation processing unit (11) for opening a space, and a region opening processing unit (12) for re-creating a segment table according to a used region size and opening a virtual address space when opening a region; A virtual address space management processing method characterized in that a virtual address space is dynamically opened according to a used region size.