JPS6037931B2 - List processing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a list processing device, in particular, data having a binary list structure is connected by a cell having a left pointer pointing to subsequent data and a right pointer also pointing to subsequent data, In a list processing device having an input/output mechanism, an interpretation/execution mechanism, and a main memory management mechanism, the main memory management mechanism adopts a virtual memory system having a main memory section and an external storage section, and expands the storage area to a large extent. The present invention relates to a list processing method that efficiently uses the necessary cells when creating a list structure.

Electronic computers are widely used in fields that process numerical data, but it is expected that they will become widespread in fields that handle symbolic data in the future.

Needless to say, this will greatly contribute to the advancement of the technology called artificial intelligence. Particularly in applications such as robots, medical diagnosis, and natural language understanding, programs written in LISP, a language that can process data as symbols, have recently been rapidly developed. The LISP language has powerful functions for processing symbols and lists, and it is very easy to use because the user does not need to manage memory. ) internal processing such as garbage collection is extremely complex. An object of the present invention is to efficiently manage the memory of a LISP machine that executes the LISP language.

This LISP machine will be called a "list processing device", and the general concept of the list processing device will be explained. A list processing device executes a program by processing a list configured on main memory.

The configuration of the list processing device is shown in FIG. The program input from the terminal 1 is stored in the storage device 3 by the processing system 2.
It is converted into a list structure as shown in the J list area 4 and stored in the list area 4. When input processing is completed, processing system 2
interprets the list structure, executes it, and outputs the result to the terminal. As shown in the figure, the functions of the processing system 2 are roughly divided into three parts: (1) input/output mechanism 5, (b) interpretation/execution mechanism 6, and (m) main memory management mechanism 7. The input/output mechanism 5 works with the main memory management mechanism 7 to create lists in the list area 4 as necessary based on programs or data input from the terminal 1.

Furthermore, it has a function of outputting the execution results to the terminal 1. The interpretation/execution unit 6 executes the program based on the input/output unit 5 and the list. Main memory management mechanism 7
's main job is cell management. The storage area in the list processing device is treated as list area 4, and list area 4
is a set of cells 8. Cells in use are treated as free cells, and all free cells are connected via pointers. The interpretation/execution mechanism 6 consumes free cells more and more in the process of executing the program, but
Once used, all cells become garbage except for the cells (lists) used in the next step. Therefore garbage
Collection is required, but conventional main memory management mechanism 7
When there were no more free cells, garbage processing was activated and garbage was collected. However, as the number of cells increases, the time required to distinguish the cells from cells currently in use and find the garbage becomes very large.
FIG. 2 shows an aspect of conventional garbage processing.

In the case shown in FIG. 2, the main memory management mechanism 7
In addition, it has a bit map 9 corresponding to all cells 8 in the list area 4. In the bit map 9, one bit corresponds to one cell, and if the bit is ON, the corresponding cell is in use, and if the bit is OFF, the cell is unused. Furthermore, the main memory management mechanism 7 prepares a usage list terminal 10 for the list currently in use. When the garbage processing is started, the bit map 9 is first cleared, the cell 8 in use is searched based on the usage list terminal 10, and the corresponding bit map 9 is cleared.
Turn on the bit. In this manner, the bit map is completed when all the cells in use have been marked. An OFF bit in bit map 9 indicates that the corresponding cell is unused, and the garbage processing routine finds unused cells, creates a free list, and completes the task. Note that there is also a marking-based garbage processing method that is realized by having one marking bit in each cell. At this time it is 1
It is sufficient to read the cell once, set the bit, and write to the cell, but the task of searching for a free cell is the same as in the case shown in FIG. Such a list structure having cells in use and cells for inconvenience (free cells) is formed using the entire storage area if the storage area is within the real address space that is directly managed by the control unit.

However, as the amount of information handled increases, the main storage area alone cannot handle the processing, so it becomes necessary to adopt a virtual storage system that uses a real storage area and a virtual storage area.

An object of the present invention is to provide an efficient list processing method for managing storage areas in units of fixed blocks (hereinafter referred to as pages) when performing list processing in a processing system using a virtual storage method. do. In order to achieve the above object, the present invention utilizes a virtual memory method that controls page units in a list processing method that processes information by connecting cells, which are storage units of a storage area, with pointers and forming a list structure. , a status information indicating whether or not a page having free cells is accommodated in the real storage area is provided, and based on this information, free cells in the page in the real storage area are used preferentially.

Hereinafter, the present invention will be explained in detail with reference to Examples.

FIG. 3 is an explanatory diagram of the virtual storage system used in the present invention.

In the figure, RM is a real storage area, which is a main storage area in terms of hardware, and VM is a virtual storage area, such as an external auxiliary storage device. 41 to 50' indicate each page of the storage area, and each page has a logical address from address 0 to YYY, and a real address is attached to the page in the real storage area RM.

This virtual storage method is a well-known one, and for logical address real address conversion, page memories PM are provided for the number of pages, and each page memory 51 has a flag 62 indicating whether it is in the main storage area or not.
and the real address 53 if the page is in main storage. By managing each page using this page memory PM, pages necessary for processing the virtual storage area VM are read out to the real storage area PM as shown in the figure. FIG. 4 conceptually shows an example of a free cell list of the IJ strike processing method using the virtual memory method. 54 and 57 are pages on the memory, and 55 and 56 are pages on the external memory.

As explained earlier, when the processing system requires free cells, it forms a free list and uses cells from the list, but unlike the case where the list is formed only in the main storage area, the real storage area RM Since a free list is formed in the entire virtual storage area VM, it is necessary to form a free list within a page and to form a free list (connection) between pages. If this free list formation is connected like normal memory block linkage, during list processing, the next page or cell will only be accessed after the link (pointer) of each page or the link (pointer) of each cell is indexed. It is determined whether it is in the real storage area or the virtual storage area. When manipulating FreeCell based on the processing system's FreeCell request, there is no problem if the page that accommodates FreeCell is in the real storage area, but if it is in the virtual storage area, the page must first be read out to the real storage area. The following page control processing is required. This page control normally requires time on the order of milliseconds because the virtual storage area is an external storage area (for example, a magnetic disk). Therefore, the more pages are read between the real storage area (the internal processing time is in nanoseconds) and the virtual storage area, the lower the efficiency of list processing becomes, leading to interruptions in information processing that requires real-time processing. The disadvantage is that it becomes long. The present invention solves this drawback by using a virtual storage method and improving the efficiency of storage processing.

FIG. 5 shows a page control word according to the method of the present invention. C.W.
is a page control. This CW has several pages and is part 4.
Arranged in the order of logical page addresses of the virtual storage area VM shown in the figure, each page control word 61 has a free cell display 63 indicating the presence or absence of a free cell in the second page, and an area flag indicating whether or not the own page is in the real storage area. 62 and a pointer 64 indicating the address of the next page control word. Figure 6 is the 5th
This diagram conceptually shows the usage status of the page control words in the figure. Free cells in each page are displayed in the free cell display 63 (for example, "1"), and those page control words are displayed in the free cell display 63. Link with pointer 64.

A page control word group having free cells is formed by linking the leading and trailing ends of the page control word having free cells to a head pointer HP70 and a tail pointer TP71. Similarly, for pages consisting of cells that are in use or cells that do not form a list (garbage cells), the free cell display 63 of the page control word is not displayed (for example, "0"), and those page control words are Link with pointer 64, head pointer HP72,
By linking to tail pointer TP73, a page control word group without free cells is formed. FIG. 7 schematically shows a page corresponding to one page control word shown in FIG. 6, where 80 is a page, 81 is a head pointer of free cells within the own page, and 83 is a free cell list. be.

When a page is controlled as shown in FIG. 7 with the cell configuration shown in FIG. 7, when the processing system needs an empty cell, it indexes the page linking the free cells in a list form from the head pointer HP 70 and first pages the page. The area flag 62 of the control word CW is read and it is determined whether or not it is on the real storage area RM, and processing for pages in the real storage area is proceeded.

FIG. 8 is a concrete block diagram for realizing the list processing method of the present invention.

In the figure, 90 is an address register, 91 is an address decoder section 92, a register for extracting the area flag 62 of the page control word 61, 94 is a register for extracting a pointer (indicating the next page control word), 95 is a read register, and 96 is a register for extracting the area flag 62 of the page control word 61.
is the tail pointer 7 indicating the end address of the page control word.
1 (or 73) and compares the contents of register 94, 97 is a page replacement control unit, 10 is a readout line that reads out the contents of the pointer when a page with an empty cell is detected in the storage area, and AD is The configuration of addresses in the virtual storage system is shown, where 98 is a page address and is a value entered in the pointer 61, and 99 corresponds to an intra-page address. In other words, the address AD specifies a page using a page address, and specifies one memory area using an intra-page address. In FIG. 8, an example will be explained in which a free cell operation is performed.

First, the contents of the head pointer 70 with the free cell are set in the address register 90, and the address decoder section 91
The page control word specified by is read into the registers 92 and 94. Area flags 62, 9 of read page control word
If G.2 is "0", it is determined that the page does not exist in the real storage area wide M, and gate G.2 is "0". opens, sets the contents of the pointer 94 to the address register 9, and reads out the next page control word. If the area flag is "1", gate ○2 opens, reads out the contents of the address register 90, sets it in the register 95, and captures a free cell in the page pointed to by a control unit (not shown) via the logical line 100. do. When a page with free cells is not in the real storage area, the till pointer and the pointer 95 of the last page control word are compared in the comparison circuit 96, and when they match, the page replacement control unit moves the page from the virtual storage area to the real storage area. Read aloud. Then, the control word 61 corresponding to the page read out to the real storage area
The area flag 62 of is set to "1". On the other hand, the area flag 62 of the control word 61 corresponding to the page pushed out from the real storage to the virtual storage area is set to "0". In the above explanation, the case of taking out the listed free cells has been explained, but the same applies to the cells in use.

Next, the replacement of page control words will be explained using FIG. 9. Pointer HP when taking out free cells
Then, the page control words P, .about.P2 are indexed and free cells are extracted from the page in the real storage area.

At this time, the area flag of each page control word is checked as explained above, and if it is not on the real storage area, the corresponding page control word is linked after the last page control word indicated by the til point. FIG. 9 shows a case where the page control word P is not in the real storage area, and shows how pointers are rearranged as shown by broken lines. In addition, the processing system uses the free cells sequentially, and when there are no more free cells in the page, the corresponding page control word is removed from the page control group containing the free cell, and the free cell display flag of the control word is set to "0" and the till point of the page control group without free cells ("73" in Figure 6).
(denoted by ).

On the other hand, as cells are used, the number of page control words with free cells decreases, and the number of page control words without free cells increases. Collect inconvenient cells (garbage cells) from within the page corresponding to the first page control word of the page control word group without , create a list of free cells again, and add this page control word to the page control word group with the free list. Connect to the end.

Then, set the free cell display 7 lag of the page control word to “1”.
In the relationship between the area flag of the page control word and the virtual storage method, when reading a page to the real storage area, the page memory is rewritten with the page control word.

In other words, the real storage area of the relevant page is displayed and the real address is displayed as a third page so that the logical address can be converted to a real address.
Since it is managed by rewriting the page memory shown in the figure,
At the same time, by rewriting the area flag of the page control word, page management becomes possible even in list processing. In addition, in list processing, the number of pages in the real storage area that are in the real storage area and are in the page control word group that have free cells is counted in a register, etc., and if the count becomes less than a certain number, By replacing pages, it is possible to always secure a certain amount of pages with free cells in the real storage area.

As explained above, according to the list processing method of the present invention, when a new cell is required in a virtual storage system, a page control word group in which free cells exist is used from those in the real storage area. You can swap pages (
(Usually called t of Pa bag Fa) can be minimized,
Processing time can be reduced and the processing capacity of the processing system can be improved.

[Brief explanation of drawings]

Figure 1 is an explanatory diagram explaining the concept of the list processing device, Figure 2
FIG. 3 is an explanatory diagram illustrating garbage processing, FIG. 3 is an explanatory diagram of a virtual storage method to which the present invention is applied, and FIG. 4 is an explanatory diagram conceptually showing an example of a strike processing method using the virtual storage method. FIG. 5 is a configuration diagram of a page control word according to the list processing method of the present invention, FIG. 6 is an explanatory diagram conceptually showing the state of use of the page control word in FIG. 5, and FIG. 7 is a diagram of one page control word. FIG. 8 is a concrete block configuration diagram for realizing the list processing method of the present invention, and FIG. 9 is an explanatory diagram showing an example of controlling a page control word. PM: Real storage area, VM: Virtual storage area, PM: Page memory, CW: Page control word, HP: Head pointer,
TP: Tail pointer, 9 0: Address register, 9
2, 94: Register, 95: Issue register, 96: Comparison circuit, G,, ○2: Gate. Figure 1 Figure 2 Figure 4 Figure 5 Figure 6 Figure 7 Figure 3 Figure 8 Figure 9

Claims (1)

[Claims] 1. When using a virtual memory method on a page basis in a list processing method that processes information by forming a list structure in which cells, which are storage units of a storage area, are connected using pointers,
A list processing method characterized in that information indicating whether or not a page having free cells is accommodated in a real storage area is provided, and based on the information, free cells in pages in the real storage area are used preferentially.