JPS6214244A - Virtual storage control system - Google Patents

Abstract

PURPOSE:To avoid the redundant load of the logical page in the paging control by providing the flag to show that the data copying processing is being executed in the garbage collection and the border register to show the copying destination area. CONSTITUTION:For the copying-type garbage collection system, a flag 20 to show that the data copying processing is being executed from one side area to other side area and a border register 21 to show the copying destination area are provided. When the logical page of the access destination is not loaded to a main storage device, the flag 20 displays that the copying processing is being executed and said access destination is located in the copying destination area displayed at the border register 21, the logical page is not loaded from the storage device and the copying destination logical page is set on the main storage device.

Description

[Detailed Description of the Invention] [Summary] This is a paging control method for a virtual storage system. When a LISP program is executed in a virtual storage system, there is a copy type garbage collection method in which two areas are provided in a logical space and used alternately.

In that case, a flag is set to indicate that the garbage collection is being copied, and if the logical page to be copied is not in the main storage during the copying process, the page area is allocated to the main storage without loading that logical page. Use it as is as a logical page. This eliminates the need to load pages to be copied and updated, reducing overhead.

[Industrial application field]

The present invention relates to a paging control method for a virtual storage system in an information processing system.

As is well known in the virtual storage system of many information processing systems, the logical space is managed by dividing it into logical pages of a certain size, and when an access request occurs, the logical page is transferred to the main memory. If the logical page does not exist in the device, a method is adopted in which the relevant logical page is loaded from an external storage device that holds a logical space to the main storage device and accessed.

In the case of write access in such a system, even if a logical page load is performed, if the valid contents of that logical page are all updated regardless of the previous contents, the previous contents will be loaded. What you do is actually a waste, so at least if it is clear in advance that such an access will be performed, it is desirable for processing efficiency to be able to take up page space on main storage without performing the load. .

[Prior art and problems to be solved by the invention] FIG. 3 is a block diagram showing an example of the configuration of an information processing system.

↑a The control device 1 includes a processing device 2, an input/output processing device 3,
The main storage device 4 is connected and access between these devices is controlled.

The processing device 2 accesses the main storage device 4 via the storage control device 1, executes the program held in the main storage device 4, and processes the data also held.

The input/output processing device 3 is connected to a storage device 5 made up of, for example, a magnetic disk storage device, and executes programs between the storage device 5 and the host device 1a 4 according to instructions from the processing device 2.
Controls the transfer of data, etc.

In the case of the virtual storage method, the contents of a logical space, which usually has a sufficiently larger area than the storage area of the device 1a, is held in the storage device 5 and managed by dividing it into logical pages of a certain size (for example, 4 kilobytes). Ru.

Those logical pages can be accessed from the processing device 2 only after being loaded into the main storage device 4.
A logical address generated from a program executed in
(address in the logical space) is converted into a real address (a storage address on the main storage device 4) at which the corresponding logical page is loaded by an address translation mechanism and a storage management program provided in the known processing device 2. access is performed.

When an access request is issued by the processing device 2, if the corresponding logical page does not exist in the main storage device 4 (this condition is referred to as an at-page fault), the required logical page is stored using known paging control by the storage management program. It is loaded from the storage device 5 to the main storage device 4.

If the logical page loaded into the main storage device 4 by the above paging control is updated with different data without referring to the previous content, only the new data becomes valid data. Then, the contents of the logical page held in the storage device 5 are transferred to the main storage device 4.
In the end, it turned out to be a complete waste of money.

Therefore, if it is determined that such processing will be performed when a page fault occurs for that logical page, paging control based on such access requests will simply involve 1 page 1i
All you have to do is make llJ1 empty and consider it as the corresponding logical page (the one loaded).

An example of a case where such a processing mode is determined from the time of a page fault is a page fault during garbage collection during execution of a LISP program or the like.

As is well known, a program written in the programming language LISP processes data that constitutes a list, and a list is data chained by pointers in a predetermined format, and in general, the list is expanded or contracted as processing progresses. In addition, as pointers are reconnected, etc., the data area in the logical space gradually becomes full of irregular empty areas, resulting in an effective area shortage.

In such a state, the process of organizing data areas and collecting free areas is called garbage collection.

In the copy type garbage collection method, which is a type of garbage collection method, as shown in Figure 4, two
Two data areas 1O111 are provided, and one data area (
For example, if garbage collection becomes necessary as a result of proceeding with the execution of the SP program using the data area 10), data 12 of the valid list distributed in the data area 10 is exemplified as data 13 in the data area 11. The results of garbage collection are obtained in the data area 11 by arranging and copying the data as shown in FIG.

After that, the LISP program is controlled to continue executing the data area 11.

In such garbage collection processing, for example, transferring one piece of data from the data area 10 to the data area 11 involves reading out the data within one logical page of the data area 10,
To the logical page of data area 11, for example, data area 11
Since the logical page is sequentially used and transferred from the first logical page, if a page fault occurs during this time, it is loaded from the storage device 5 as described above.

As is clear from the above description, data is simply written to the logical page of the data area of the data transfer destination, and only the newly written data becomes valid data.

Therefore, although this logical page does not need to be loaded from the storage device 5, general paging control will result in unnecessary loading.

[Means for solving problems]

FIG. 1 is a block diagram showing the configuration of the present invention.

In the figure, 20 is a flag indicating that data copy processing is in progress in garbage collection, 21 is a boundary register indicating a copy destination area, 22 is a garbage collector, and 23 is a storage management program.

[For production]

The garbage collector 22 sets a flag 20 to indicate that processing is in progress at the start of processing, and also sets an address in the boundary register 21 that indicates the area to be copied by garbage collection.

When a page fault occurs and the storage management program 23 starts processing, first it is determined whether the flag 20 indicates that the process is in progress, and if the process is in progress, it is determined whether the address of the access request destination is within the area indicated by the boundary register 21.

As a result, if the access destination address is identified as the copy destination area, the storage management program 23 sets a free page area of one page in the main storage device 4 using a known method, and uses this as the requested area. Set up the address translation mechanism so that it can be accessed as a logical page.

The above configuration makes it possible to avoid redundant loading of logical pages in paging control.

〔Example〕

In FIG. 1, the garbage collector 22 and the storage management program 23 execute the same processes as the conventional garbage collection processing program and storage management program, respectively, as described above, except for performing the control described below. Garbage collection is performed using the copy type garbage collection method as described above.

In the following description, reference will be made to the process flowchart of FIG. 2 as well as FIG. 1.

When one of the data areas 10111 illustrated in FIG. 4 is being used and a large amount of free space runs out, the garbage collector 22 is called.

Garbage collector 22 performs step 30 of the process of FIG.
At step 31, the flag 20 is set to indicate the processing in progress, and at step 31, an address indicating the area to be copied by garbage collection is set in the boundary register 21.

For example, specific registers within the processing device 2 are used as the flag 20 and the boundary register 21. It is assumed that the start address and end address of the area 10 or 11 shown in FIG. 4 are set in the boundary register 21, for example.

The garbage collector 22 then proceeds to step 32 and executes garbage collection processing in the same manner as before.

When a page fault occurs in the process of step 32, control is passed to the storage management program 23. In the first step 40, the storage management program 23 determines whether the flag 20 indicates that processing is in progress, and if it does not indicate that processing is in progress, it executes normal paging control from step 41 onwards.

That is, in step 41, a free page area is taken in the main storage device 4, and in step 42, the storage device 5 is allocated to that page area.
When the load is complete, step 43 sets up the address translation mechanism to access the logical page, and then returns control to the point where garbage collector 22 left off in step 32.

If the flag 20 indicates that processing is in progress, it is determined in step 44 whether the address of the access request destination is within the copy area indicated by the boundary register 21.

As a result, if the access destination address is not in the copy destination area, the process advances to step 41 and normal paging control is executed in the same manner as described above.

If it is determined that the access destination address is the copy destination area, in step 45, 1 is stored in the main storage device 4.
After setting the free page area of the page and making it the logical page of the request, proceeding to step 43 and setting up the address translation mechanism to access this page, the garbage collector 22 returns to the break point of step 32. Return.

When the garbage collector 22 completes the process in step 32, it resets the flag 20 in step 33 and completes the garbage collection.

〔Effect of the invention〕

As is clear from the above description, according to the present invention, in a virtual memory type information processing system, redundant 0-words of logical pages are omitted in paging control, the overhead of paging control is reduced, and paging control is reduced. Since the processing time is shortened, garbage collection and the like become faster, which has a significant industrial effect of improving the processing efficiency of the information processing system.

[Brief explanation of drawings]

Fig. 1 is a block diagram of the configuration of an embodiment of the present invention, Fig. 2 is a flowchart of the processing of the present invention, Fig. 3 is a block diagram of an example configuration of an information processing system, and Fig. 4 is a block diagram of an example configuration of an information processing system.
The figure is an explanatory diagram of garbage collection. In the figure, 1 is a storage control device, 2 is a processing device, 3 is an input/output processing device, 4 is a main storage device, 5 is a storage device, 10
．． 11 is a data area, 20 is a flag, 21 is a boundary register, 22 is a garbage collector, 23 is a storage management program, 30 to 33, and 40 to 45 are processing steps.

Claims (1)

[Scope of Claims] Data in a logical space consisting of a plurality of logical pages is held in a storage device, and the required logical pages are loaded from the storage device to the main storage device and accessed when necessary. , in a given case, of two given areas in the logical space,
In an information processing system configured to alternately use the two areas by copying data held in one area to the other area, processing for copying data from the one area to the other area. A flag (20) indicating "inside" and a means (21) for displaying a copy destination area are provided, and when the logical page to be accessed is not loaded in the main storage device, the flag (20) indicates that the copy process is not executed. If the access destination is within the copy destination area displayed on the display means (21), the logical page is stored on the main storage device without being loaded from the storage device. A virtual memory control method configured to set a copy destination logical page.