JPH02217942A - Automatic paging system for computer system - Google Patents

Abstract

PURPOSE:To reduce overhead to an operating system(OS) by executing paging processing at the level of a hardware without generating an interruption to the OS due to page exception (address conversion exception). CONSTITUTION:An automatic paging processing part 200 executes the page-in/ page-out operation of a main storage 107 and an extended storage area 108 and the updating operation of tables 106, 109. When an page exception (address conversion exception) is generated in an address conversion process, a page paged out in the area 108 is automatically read out from the area 108 without generating a page exception interruption to the OS and then paged out in a main storage area 107. Consequently, the overhead on the OS side can be reduced and the through-put of the whole system can be improved.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to an automatic paging method for a computer system, and relates to a computer system using a virtual memory method in which multiple programs are executed on the main memory while being multiplexed using paging. relates to an automatic paging method suitable for reducing O8 overhead in a state where paging frequency is high.

[Conventional technology]

In a conventional virtual storage computer system, when a page that has been paged out to an external medium (auxiliary storage) is referenced or updated in the main memory.

The hardware reports the page exception to the operating system (O8), the O8 searches for the page from the paged-out external media, and restarts the program after the page is transferred to main memory. It is a method.

Regarding this type of paging method, please refer to Masahiko Senda's [Function and Structure of Large Operating System MVS].
Discussed on page 31 (Kinda Kagakusha).

[Problem to be solved by the invention]

In the above conventional technology, the occurrence of a page exception is handled as an interrupt.
In order to notify O8, it analyzes the cause of the interrupt, interrupts the program that caused the page exception, and
It will find out where the required page area is located on the external medium that has been paged out, and instruct the hardware to transfer that page to main memory. Further, the instructed hardware transfers the requested page to the main memory, and after the transfer is completed, O8 puts the program into the restart state again, and the execution of the program is resumed.

In this way, in the conventional technology, O8 has to interrupt processing and perform page-in processing.
There is a problem in that when paging occurs frequently, the overhead becomes enormous, and the performance of the entire system decreases accordingly.

An object of the present invention is to provide an automatic paging method that makes it possible to reduce overhead on the O8 side when a page exception occurs and improves the throughput of the entire computer system.

cam] In order to achieve the above object, the present invention provides a means for solving the problem without interrupting the page exception to the operating system when a page exception (generally an address translation exception) occurs during the address translation process. The present invention is characterized in that an automatic paging processing means is provided for automatically reading pages paged out to the extended storage area from the extended storage area and paged out to the main storage.

[For production]

The computer system is equipped with an address translation management table and a main memory management table, and the address translation management table includes:
A page-out indicator that shows whether a page in main memory is paged out to expanded storage, an address in main memory if it is paged in to main memory, and a page that is paged out to expanded storage. In this case, the address on the extended storage area is registered, and in the main memory management table, corresponding to each page on the main memory, there is a page empty indicator indicating whether the page is empty or not, and a page empty indicator indicating whether the page is empty or not. The above address is registered.

The address translation means (dynamic address translation mechanism) that translates the virtual address of the access request source into a real address refers to the address translation management table.

If the page-out indicator indicates page-out, it is determined that this is an address translation exception and automatic paging processing means is activated. The activated automatic paging processing means refers to the main memory management table, secures a free space on the main memory, and transfers the page of the extended storage area indicated by the extended storage address of the address conversion management table to the main memory. Transfer to the empty area of main memory indicated by the main memory address of the table.

(Example〕 An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows the relationship between an automatic paging processor and a dynamic address translation mechanism (DAT) according to the present invention. In FIG. 1, the Agile translation table is divided into two levels, and when converting to a virtual address, a method is adopted in which a segment table is first searched and then a page table is searched.

In FIG. 1, 100 is a control register that stores the segment table start address, and 101 is a virtual address register that stores the virtual address (logical address) of a memory access request. The virtual address is segment field 111. Page field 112. It consists of a displacement field 113. 102 is a real address register that stores the converted real address.

103 and 104 are adders. 105 and 106 are configuration requests for an address translation table used when converting to a virtual address; 105 is a segment table;
106 is a page table. Here, each entry in the page table 106 has a page out indicator (
Page exception indicator: page out indicator) 101
, a pointer (real page address) on the main storage area when it is actually paged in 162. Consists of a pointer 163 on the extended storage area when paged out. 1
07 indicates one page on the main storage area, and lO8 indicates one page on the extended storage area.

109 is a main memory management table, and each entry includes a page indicator (page empty indicator) 191 and a page pointer 192 on the main memory area.

Reference numeral 110 denotes a real address determination unit that determines whether or not there is a page exception in a real address. Reference numeral 200 denotes an automatic paging processing unit introduced according to the present invention, which executes page-in/page-out operations for the main storage area 107 and extended storage area 108, and update operations for tables 106 to 109.

The operation of FIG. 1 is as follows. When the virtual address of a memory access request is set in the virtual address register 101, the adder 103 adds the segment table start address of the control register 100 and the segment field 111 of the virtual address to obtain the entry address of the segment table 105. Then, add this page table address and the page field of the virtual address in the adder 104 to obtain the entry address of the page table 106. The real address determination unit 110 that reads the contents of the corresponding entry takes in the contents of the entry read from the page table 106, and if the page out indicator 161 does not indicate a page exception, determines that the real page address 162 is valid. The real page address is stored in the upper part of the real address register 102.

At this time, the displacement field 113 of the virtual address register 101 is stored in the lower part of the real address register 102. The main memory is accessed by the real address in the real address register 102.

The operation when the above page exception does not occur is the same as before.

If the page out indicator 161 of the entry read from the page table 106 indicates a page exception, the real address determination unit 110 activates the automatic paging processing unit 200. In response to this concern, the automatic paging processing unit 200 first performs the following steps.

Page indicator 191 of main memory management table 109
Allocates an empty page 107 in the main storage area and stores the pointer 16 of the entry read from the page table 106.
The page 108 in the extended storage area indicated by 3 is transferred to the page 107 in the main storage area (page-in). The automatic paging processing unit 200 updates the page out indicator 161 and real page address 126 of the corresponding entry in the page table 106, and also updates the main memory management table 1.
The corresponding page indicator 191 in 09 is updated. The operation path of this automatic paging processing section 200 is shown by a broken line in FIG.

After that, when the address translation operation is performed again, the page out indicator 161 of the corresponding entry in the page table 106 has been updated.

A page exception does not occur and a real address is obtained in the real address register IO2. Note that the real page address is determined as a page pointer in the main memory management table 109 during the paging operation by the automatic paging processing unit 200, so if this is used, restarting the address translation operation can be omitted.

Next, the operation of the automatic paging processing section 200 will be described in detail.

Figure 2 is a page table (address conversion management table)
, which shows the relationship between the main storage management table, main storage, and extended storage. The main memory 300 has 30 evenly spaced pages.
It is divided into multiple parts called 1. Extended storage area 400 is also managed by page 401.

On the other hand, each of a plurality of programs that are multiplexed and executed within the computer is stored in a page 301 on the upper memory 300.
In the same way, all addresses in virtual space are divided and managed in page units.

Of the pages in this virtual space, the page table 106 manages pages that are paged in to the main memory, and also manages pages in the virtual space that are paged out to the extended storage area. . page table 10
6, when a program is accessed for the first time, a table for that page is prepared along with a segment table.

This page table 106 corresponds to each entry.

Page out indicator (page exception indicator)
161 and main memory 3 when actually paged in
Pointer (real address) 162 on 00, pointer 163 on extended storage area 400 if paged out
have. Page out indicator 161 is II
At O11, the page exists on the main memory 300 (page-in), and the page address of the main memory 300 at this time is indicated by the pointer 162. At this time, the extended storage area pointer 163 has been cleared. Conversely, when the page out indicator 161 is "1", the corresponding page exists on the extended storage area 400. The pointer 163 indicates the page address on the extended storage area 400 at this time. Note that if the entry area of the pointer 162 is set to one and the page out indicator 161 is "0", the main memory pointer 16
2, and extended storage pointer 16 when ll I II.
3 may be registered respectively.

The main memory 300 itself is managed by a main memory management table 109. Each entry in this main memory management table 109 has a one-to-one correspondence with a page on the main memory 300, and a page indicator 191 indicates whether the page is empty or in use. It has a pointer (real page address) 192 on the main memory 300 of the page. The page indicator 191 is 110'' when the page is completely empty on the main memory 300, and is "1" otherwise.

FIG. 3 is a diagram illustrating page-in processing by the automatic page processing unit 200 when a page exception occurs, and FIG. 4 is a flowchart of the processing.

When the real address determination unit 110 in FIG. 1 detects the occurrence of a page exception during the address conversion process, the automatic page processing unit 110
Start 00. The page exception is the page table 106
Page out indicator 16 for the corresponding entry in
The automatic paging processing unit 200, activated by the real address determination unit 110, determines whether 1 indicates 1'' (step 201).
The page 401 that has been paged out is obtained from the extended storage pointer 163 of the corresponding entry in the page table 106 (step 202).

Next, the storage management table 109 is searched to obtain the main storage pointer (main storage page address) 192 whose page indicator 191 is "0"', and the main storage 309 is
Allocate an empty page 302 at the top (step 203), and then move from page 401 of extended storage area 400 to main memory 300.
Transfer one page to the empty page 302 (Step 2
04), at this time, page 401 of extended memory 1Ii400
The address of page 302 of main memory 300 is indicated by pointer 162 of page table 106, and the address of page 302 of main memory 300 is indicated by pointer 192 of main memory management table 109. When the page transfer is completed, the page indicator 191 of the corresponding entry in the main memory management table 109 is set to '1'', and the main memory pointer (real page address) 192 is set to the main memory pointer 162 of the corresponding entry in the page table 106. and page out indicator 161
is set to 110'' (step 205), and the expanded storage pointer 16 of the corresponding entry in the page table 106 is set to 110'' (step 205).
3 is cleared. Finally, the dynamic address translation mechanism (D
AT) is started again (step 206).

When the address conversion is restarted by the above processing, the page exception is not detected because the page out indicator 161 of the corresponding entry in the page table 106 is "0", and the main memory pointer 162 is stored as a real address in the real address register 100. , and the page 302 paged into the main memory 300 will be accessed.

FIG. 5 is a page-out processing flow by the automatic paging processing unit 200. Page out is performed when a two-page exception occurs and there is no empty page on the main memory 300, or when there is an unnecessary page. First, a desired page to be paged into the main memory 300 is transferred to an arbitrary empty page on the expanded storage area 400 (
Step 211), Next, set the expanded storage pointer 162 at the end of the corresponding entry 1 in the page table 106. Step 212), page out indicator 16
1 to II 1 ++ (step 213).

Finally, regarding the main memory management table 109, the main memory 3
The page indicator 191 of the entry corresponding to the page paged out from 00 is set to it O++ (step 214).

As described above, in this embodiment, it is possible to continue processing without notifying the O8 of a page exception interrupt that occurs during program processing.

〔Effect of the invention〕

As is clear from the above description, one aspect of the present invention is as follows.

Since paging processing is performed at the hardware level without generating interrupts to O8 due to page exceptions (generally address translation exceptions), which have traditionally been essential in virtual memory computer systems, the overhead for O8 is significantly reduced. It is possible to improve the throughput of the entire system. This effect becomes particularly noticeable when the multiplicity of the system increases (when the system is extremely crowded).

[Brief explanation of the drawing]

Fig. 1 is a diagram showing the relationship between the automatic paging processing unit and the dynamic address translation mechanism according to the present invention, Fig. 2 is a diagram showing the relationship between each management table, main memory, and extended storage area, and Fig. 3 is a diagram showing the relationship between the automatic paging processing unit and the dynamic address translation mechanism according to the present invention. 4 and 5 are diagrams explaining the page-in processing of the automatic paging processing section,
It is a flowchart of page out processing. 100...Control register. 101...Virtual address register. 1, 02...Real address register, 103.104...Adder, 105...Segment table. 106... Page table, 161... Page out indicator. 162...Main storage pointer, 163...Extended storage pointer, 109...Main memory management table, 191...Page indicator, 192...Main storage pointer, 110...Real address determination Department. 200... Automatic paging processing section, 300... Main memory, 400... Extended storage area. Figure 2 Figure 1 'HBZ, 3-cho-cho-+!し [2222; 2222 [222222222] f71″
Figure 3 Figure 4 Figure 5

Claims (4)

[Claims] (1) In a computer system that uses a virtual memory method and performs page-in/page-out page movement between main memory and extended storage as necessary, the virtual address issued by the main memory access requester is converted into a real address. When the address translation means detects an address translation exception, it automatically converts the page that has been paged out to the extended storage area without causing an interrupt for the address translation exception to the operating system. An automatic paging method for a computer system, comprising: automatic paging processing means for reading from the extended storage area and paging into main memory. (2) The computer system includes an address conversion management table and a main memory management table, and the address conversion management table includes a page-out indicator that indicates whether a page in the main memory has been paged out to the extended storage area, and a page-out indicator that indicates whether a page in the main memory has been paged out to the extended storage area The main memory management table corresponds to each page in main memory. and a page empty indicator indicating whether the page is empty.
The address conversion means has an address on the main memory of the page, and when converting the virtual address of the access request source into a real address, refers to the address conversion management table and if the page out indicator is set. , determines that it is an address translation exception and starts the automatic paging processing means, and when the automatic paging processing means receives the activation,
The above main memory management table is referenced to secure a free area on the main memory, and the page of the extended storage area indicated by the extended memory address of the above address conversion management table is transferred to the main memory indicated by the main memory address of the above main memory management table. 2. The automatic paging method for a computer system according to claim 1, wherein the paging is transferred to an empty area of the computer system. (3) When the automatic paging processing means transfers the page paged out to the extended storage area to the main memory, the automatic paging processing means updates the page empty indicator corresponding to the page in the main memory management table to "in use", and also updates the page empty indicator corresponding to the page in the main memory management table to 3. The automatic paging method for a computer system according to claim 2, wherein the page-out indicator of the corresponding entry in the conversion management table is reset, and the paged address on the main memory is set. (4) When the automatic paging processing means pages out the page paged in to the main memory to the extended storage area,
Update the page empty indicator for the corresponding page in the main memory management table to empty, set the page out indicator for the corresponding entry in the address conversion management table, and set the paged out address on the expanded storage area. An automatic paging method for a computer system according to claim 2, characterized in that: