JPH02166536A - Method and device for controlling main storage - Google Patents

Abstract

PURPOSE:To prevent the abnormal end of a work program by recalculating the remaining idle memory capacity after complying with a memory acquiring request received from an applied work program and giving a warning to an operator in case the calculated idle memory capacity is less than the warning threshold value. CONSTITUTION:An idle memory capacity recalculation part 8 complies with a memory acquiring request received from an applied work program and recalculates the remaining idle memory capacity. A warning part 11 gives a warning to an operator directly in case the calculated memory capacity is less than the designated warning threshold value. Therefore the operator can refrain intentionally from executing the applied work program which requires a new memory area after the reception of the warning. Thus it is possible to prevent the abnormal end of a produced applied work program before it happens since the recovery is difficult to the original steady state in the case the acquisition of a necessary memory area failed.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method and apparatus for managing main memory in a computer system having a limited main memory.

BACKGROUND OF THE INVENTION In recent years, computer systems have been widely used in all information processing fields. These computer systems generally include a central processing unit (CPU), a main memory, an auxiliary memory, a display, an input device, and the like. Among these components, the main memory device is generally composed of volatile memory using semiconductor elements, etc., and has a lower size than the auxiliary memory device using non-volatile memory such as magnetic recording media. Although high-speed access is possible, hardware resources are often quite limited in terms of capacity.

In order to make effective use of such limited hardware resources, modern computer systems generally have a system program called an operating system (O8) resident thereon, which centrally manages all hardware resources and manages individual application tasks. It has full control over program execution.

This system program usually includes main memory management and functions, such as acquisition of memory area for loading application programs stored in auxiliary storage into main memory, and necessary functions for application programs when they are executed. It performs control such as acquisition of memory area to be used.

However, as described above, the capacity of the main memory is finite, so the required memory area may not always be acquired. To solve this problem, we developed a computer system that uses a virtual memory method that can make the apparent main memory capacity much larger than the actual main memory capacity by using a large-capacity auxiliary storage device. has been done. Although such virtual memory methods are widely used in relatively large computer systems, they require a high-performance central processing unit, auxiliary storage, and advanced system programs, so they are not suitable for relatively small computers such as personal computers. It is not widely used in computer systems.

FIG. 2 is a block diagram of a conventional main memory management device.

In the figure, 21 is a memory acquisition request unit that instructs acquisition of a new memory area on the main memory in response to a request from an application program. The memory acquisition request unit 21 is realized, for example, in the form of a system library that is linked with an application program in the form of a function call that takes the required memory capacity as an argument, and that starts a system program by interrupt processing. Reference numeral 22 denotes a free memory management unit that manages designation information of free memory areas on the main memory. The free memory management unit 22 is referenced by a free memory capacity calculation unit 23 and a memory acquisition unit 26, which will be described later. As the designation information of the memory area, for example, its start address is used. Reference numeral 23 denotes a free memory capacity calculation unit, which refers to the management contents of the free memory management unit 22 and calculates the current capacity of free memory on the main memory. Reference numeral 24 denotes a memory acquisition possibility determination unit, which compares the acquisition memory capacity requested by the memory acquisition request unit 21 with the free memory capacity calculated by the free memory capacity calculation unit 23, and acquires the requested capacity of memory. This is to determine whether or not it is possible. Reference numeral 26 denotes a memory acquisition failure notification unit, which notifies the requesting application program that memory acquisition has failed when the memory acquisition possibility determination unit 24 determines that memory acquisition is impossible. As the memory acquisition failure notification section 26, for example, the above-mentioned memory acquisition request section 210 is used.
There is a method to return all specific negative error codes for the function call mentioned in the example.

26 is a memory acquisition unit, and the memory acquisition possibility determination unit 2
4, when it is determined that the memory area can be acquired, the memory area is actually acquired and its designation information is sent to the memory acquisition success notification unit 27, which will be described later, as well as the free memory management unit 22.
This is to update the management contents of. Reference numeral 27 denotes a memory acquisition success notification unit, which notifies the requesting application program that memory acquisition has been successful, and returns the acquisition memory area designation information sent from the memory acquisition unit 26. As the memory acquisition success notification unit 27, for example, there is a method of returning the memory designation information together with a specific return code of a non-negative value in response to the function call mentioned in the example of the memory acquisition request unit 210 described above. In reality, various other components are required to realize functions such as releasing the memory area in use, but they are not the main focus of the present invention and will therefore be omitted.

The operation of the conventional main memory management device configured as described above will be described below.

[If the requested memory review is not larger than the free memory capacity] (1) The application program is executed by the memory acquisition request unit 21
requests acquisition of a memory area of capacity R.

(2) Next, the free memory capacity calculation unit 23 refers to the first address of the free memory area managed by the free memory management unit 22, and uses the predetermined memory capacity T of the entire system to calculate the current main memory. The amount of free memory above E
Calculate = (T - people).

(3) Next, the memory acquisition possibility determination unit 24 compares the acquired memory capacity R requested by the memory acquisition request unit 21 with the free memory capacity E calculated by the free memory capacity calculation unit 23, and determines the requested capacity. Determine whether memory is available.

In this case, since R≦E, it is determined that the memory can be acquired, and a signal Y to that effect is sent to the memory acquisition unit 2e.

(4) Next, the memory acquisition unit 26 stores the capacity R after the address person.
It acquires the memory area of and sends its starting address to the memory acquisition success notification section 27, and updates the starting address of the free memory area managed by the free memory management section 22 to (MuR).

(5) Finally, the memory acquisition success notification unit 27 returns the starting address of the acquired memory area sent from the memory acquisition unit 26 to the requesting application program along with a return value of 0 indicating that memory acquisition was successful. . (End) [When the requested memory capacity is larger than the free memory capacity] (6) The application program requests acquisition of a memory area of capacity R by the memory acquisition request unit 21.

Next, the free memory capacity calculation unit 23 refers to the first address of the free memory area managed by the free memory management unit 22, and uses the predetermined memory capacity #T of the entire system to determine the current Free memory capacity on main memory E=
Calculate (TA)2.

(8) Next, the memory acquisition possibility determination unit 24 calculates the acquisition memory capacity R requested by the memory acquisition request unit 21 and the free memory capacity E calculated by the free memory capacity calculation unit 23.
It is determined whether or not the requested capacity of memory can be obtained.

In this case, since it is R)E, it is determined that memory cannot be acquired, and a signal Ni to that effect is sent to the memory acquisition failure notification unit 2.
Send to 5.

(9) Finally, the memory acquisition failure notification unit 25Fi returns a return value (-1) indicating that memory acquisition has failed to the requesting application program. (OwaL) Problems to be Solved by the Invention In the conventional main memory management method and device, as explained in the above-mentioned specific example, the success or failure of a memory area acquisition request from an application program depends on the requesting application. Since only the program is notified, a new necessary program must be added to each application program in order to notify the operator that memory area acquisition has failed. Additionally, if some application programs fail to acquire the necessary memory area, it is difficult to restore the original steady state and the program itself must terminate abnormally. During this time, the operator cannot know the possibility of success in acquiring the memory area next time, and therefore, excessive operations by the operator often result in abnormal termination of the application program as described above. Furthermore, in order to prevent such a situation from occurring, it is necessary to add a new program to each application program that calculates the remaining memory capacity each time memory is acquired and issues a warning as necessary. Ta.

In view of the above problems that conventional main memory management methods and devices have, the present invention recalculates the remaining free memory capacity after responding to a memory acquisition request from an application program. An object of the present invention is to provide a main memory management method and apparatus that can directly issue a warning to an operator when the free memory capacity is less than a prespecified warning threshold.

Means for Solving the Problems In order to achieve the above object, the present invention provides a memory acquisition request unit that instructs acquisition of a new memory area on main memory in response to a request from an application program, and a free memory capacity calculation unit that calculates the capacity of free memory above;
A memory acquisition function that compares the acquisition memory capacity requested by the memory acquisition request unit with the free memory capacity calculated by the free memory capacity calculation unit and determines whether the requested capacity of memory can be acquired. a memory acquisition failure notification unit that notifies a requesting application program that memory acquisition has failed when memory acquisition is determined to be impossible by the memory acquisition possibility determination unit; A memory acquisition unit that actually acquires the memory area when it is determined that the acquisition possibility determination unit can acquire the memory area, and a memory acquisition unit that determines the capacity of free memory on the main memory after acquiring a new memory area by the memory acquisition unit. a free memory capacity recalculation unit that recalculates; a warning determination unit that determines whether the free memory capacity calculated by the free memory capacity recalculation unit is less than or equal to a prespecified warning threshold; and the warning A main memory management device is provided, comprising: a warning section that warns an operator that free memory capacity is low when the determination section determines that the remaining memory capacity is less than or equal to a warning threshold value.

Operation The main memory management device of the present invention has the above-described configuration, so that when an application program requests acquisition of a memory area by the memory acquisition request unit, the free memory capacity calculation unit calculates the current capacity of free memory on the main memory, Next, the memory acquisition possibility determining unit compares the requested memory capacity to be acquired and the free memory capacity to determine whether the requested capacity of memory can be acquired, and it is determined that the memory cannot be acquired. In this case, the memory acquisition failure notification unit notifies the requesting application program that memory acquisition has failed, and if it is determined that the requested amount of memory can be acquired, the memory acquisition unit After acquiring the requested memory area, the memory capacity recalculation unit recalculates the free memory capacity on the main memory, and the warning judgment unit determines that the free memory capacity is less than the prespecified warning threshold. If it is determined that the amount of memory is below the warning threshold, the warning unit can issue a warning to the operator that free memory capacity is low.

Embodiment One embodiment of the main memory management device of the present invention will be described below with reference to all the drawings.

FIG. 1 is a block diagram of a main memory management device in an embodiment of the present invention. In the figure, 1 is a memory acquisition request unit;
This command instructs acquisition of a new memory area on main memory in response to a request from an application program. The memory acquisition request unit 1 is realized, for example, in the form of a system library that is linked with an application program in the form of a function call that takes the required memory capacity as an argument, and starts a system program by interrupt processing. Reference numeral 2 denotes a free memory management unit that manages designation information of free memory areas on the main memory. For example, the starting address is used as the designation information of the memory area. Free memory management section 2
are the free memory capacity calculation unit 3 and the memory acquisition unit 6, which will be described later.
．． It is referred to by the free memory capacity outside calculation unit 8. Reference numeral 3 denotes a free memory capacity calculation unit which refers to the management contents of the free memory management unit 2 and calculates the current free memory capacity on the main memory. Reference numeral 4 denotes a memory acquisition possibility determination unit, which compares the acquisition memory capacity requested by the memory acquisition request unit 1 with the free memory capacity calculated by the free memory capacity calculation unit 3, and acquires the requested capacity of memory. This is to determine whether or not it is possible. 6 is the memory acquisition failure notification section.

When the memory acquisition possibility determining unit 4 determines that v can not be acquired, the requesting application program is notified that memory acquisition has failed. As the memory acquisition failure notification unit 6, for example, there is a method of returning a specific negative error code in response to the function call mentioned in the example of the memory acquisition requesting unit 1 described above. Reference numeral e denotes a memory acquisition unit, which actually acquires the memory area when it is determined that the memory area can be acquired by the memory acquisition possibility determining unit 4, and sends its designation information to the memory acquisition success notification unit 7, which will be described later. This is to update the management contents of the free memory management section 2. A is a memory acquisition success notification unit that notifies the requesting application program that memory acquisition has been successful, and also returns the acquisition memory area designation information sent from the memory acquisition unit 6. be. As the memory acquisition success notification unit 7, for example, there is a method of returning the memory designation information together with a specific return code of a non-negative value in response to the function call mentioned in the example of the memory acquisition request unit 10 described above. Reference numeral 8 denotes a free memory capacity external calculation unit, which refers to the management contents of the free memory management unit 2 and recalculates the free memory capacity on the main memory after acquiring a new memory area by the memory acquisition unit 6. It is something to do. 9 is the warning threshold storage unit.

It stores a threshold value for determining whether or not to issue a warning that free memory capacity is low. The warning threshold storage unit 9 is referred to by a warning determination unit 10, which will be described later. 1o is a warning determination unit that determines whether the free memory capacity calculated by the free memory capacity outside calculation unit 8 is less than or equal to the warning threshold value stored in the warning threshold storage unit 9; It is. Reference numeral 11 denotes a warning unit, which warns the operator that free memory capacity is low when the warning determination unit 10 determines that the amount is below the warning threshold. The warning unit 11 may be one that displays visual information on a display device, or one that uses auditory information such as a buzzer or sound. In reality, various other components are required to realize functions such as releasing the memory area in use, but these are not the main focus of the present invention and will therefore be omitted.

The entire operation of the main memory management device of this embodiment configured as described above will be explained below.

[When the requested memory capacity is not larger than the free memory capacity and the difference is greater than the warning threshold] (1) The application program requests the memory acquisition request unit 1 to acquire all of the memory area of capacity R.

(2) Next, the free memory capacity calculation unit 3 refers to the start address of the free memory area managed by the free memory management unit 2, and calculates the predetermined memory capacity T of the entire system.
Using current free space on main memory - memory capacity E = (T
-A) Calculate i.

(3) Next, the memory acquisition possibility determining unit 4 compares the acquired memory capacity R requested by the memory acquisition requesting unit 1 with the free memory capacity E calculated by the free memory capacity calculating unit 3, and calculates the requested capacity. Determine whether memory is available. In this case, since R≦E, it is determined that the memory can be acquired, and a signal Y to that effect is sent to the memory acquisition unit 6.
Send to.

(4) Next, the memory acquisition unit 6 acquires a memory area of capacity R after the addressee and sends the first address to the memory acquisition success notification unit 7, and also free memory managed by the free memory management unit 2. Click the first address of the area
=(M+R).

(6) Next, the memory acquisition success notification unit 7 returns the start address of the acquired memory area sent from the memory acquisition unit 6 to the requesting application program along with a return value of 0 indicating that memory acquisition was successful. .

(6) Next, the free memory capacity recalculation unit 8Fi refers to the start address of the free memory area managed by the free memory management unit 2, and uses the predetermined memory capacity T of the entire system to create a new memory capacity. After acquiring the memory area, '=(T-mu°) is recalculated as the free memory capacity on the main memory.

(η Finally, the warning determination unit 1o determines whether the recalculated free memory capacity X° is less than or equal to the warning threshold S stored in the warning threshold storage unit 9. In this case, K
') Since it is S, it is determined that no warning is necessary, and the process ends. (End) [If the requested memory capacity is not larger than the free memory capacity and the difference is not greater than the warning threshold (8) The application program uses the memory acquisition request unit 1 to acquire a memory area of capacity R. request.

(9) In response to the above operation, the main memory management device of this embodiment performs the operations (2) to (6) above.

(1o) Next, the warning determination unit 10Fj: determines whether the recalculated free memory capacity X” is less than or equal to the warning threshold value S stored in the warning threshold storage unit 9. In this case , X°≦S, it is determined that a warning is necessary, and a signal Y to that effect is sent to the warning unit 11.

(11) Finally, the warning unit 11 issues a warning to the operator by outputting a message on the display device to the effect that the free memory capacity is low. (End) [When the requested memory capacity is larger than the free memory capacity] (12) The application program requests acquisition of a memory area of capacity H by the memory acquisition request unit 1.

(13) In response to the above operation, the main memory management device of this embodiment performs the operation (2) above.

(14) Next, the memory acquisition possibility determining unit 4 compares the acquired memory capacity R requested by the memory acquisition request unit 1 with the free memory capacity X calculated by the free memory capacity calculation unit 3, and calculates the requested capacity. Determine whether memory is available. In this case, since R>E, it is determined that memory cannot be acquired, and a signal Nt to that effect is sent to the memory acquisition failure notification unit 6.

(15) Finally, the memory acquisition failure notification unit 6 returns a return value (-1) indicating that memory acquisition has failed to the requesting application program. (End) As mentioned above, in the main memory management device of this embodiment, the remaining free memory capacity is recalculated after responding to a memory acquisition request from an application program, and the calculated free memory capacity is specified in advance. If the value is less than the specified warning threshold, the operator is directly warned, so that the operator can consciously refrain from running application programs that require new memory space after receiving this warning. If possible, it is possible to prevent the application program from abnormally terminating because it is difficult to restore the original steady state when acquisition of the necessary memory area fails. Furthermore, since this warning is sent directly to the operator from the main memory management unit, there is no need for each application program to add a program to notify the operator, reducing the burden on the application program. It becomes possible.

In addition, in this embodiment, we assume that the main memory is acquired in order from the beginning and that the memory area in use is not released. However, by repeatedly acquiring and releasing the memory area, It goes without saying that the main memory management method of the present invention can be applied even in situations where free memory areas on the main memory exist discretely by focusing on the largest continuous free memory area among them.

Furthermore, although this example assumes a computer system using a real memory method, the present invention can also be applied to a computer system using a virtual memory method by considering the sum of the main memory capacity and the backup auxiliary memory capacity as the main memory capacity. The main memory management method of the invention is applicable. Although the warning threshold value is also assumed to be a constant in this embodiment, it is also possible to dynamically change the warning start time by adding a means for changing the storage contents of the warning threshold storage section 9. Furthermore, by making it possible to set warning thresholds at multiple levels, it is also possible to issue warnings with different levels. Similarly, regarding notification of memory acquisition failure, not only information indicating that memory acquisition has failed is sent to the requesting application program, but also the operator is directly notified visually and audibly. It is also possible.

Effects of the Invention In the main memory management method and device of the present invention, the remaining free memory capacity is recalculated after responding to a memory acquisition request from an application program, and the calculated free memory capacity is specified in advance. If it is below the warning threshold, the operator is directly warned, so the operator can consciously refrain from running application programs that require new memory space after this warning. Abnormal termination can be prevented, and since this warning is sent directly to the operator from the main memory management device, there is no need for each application program to add a program to notify the operator. It has a great practical effect since it is possible to reduce the burden on applied business programs.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram of a main memory management device according to an embodiment of the present invention;
FIG. 2 is a block diagram of a conventional main memory management device. 1...Memory acquisition request unit, 3...Free memory capacity calculation unit, 4...Memory acquisition possibility determination unit, 6...Memory acquisition failure notification Part, 6...
...Memory acquisition part. 8... Free memory capacity recalculation unit, 1o...
- Warning determination section, 11... Warning section. Name of agent: Patent attorney Shigetaka Awano and one other person Figure 2

Claims (2)

[Claims] (1) a memory acquisition request step for instructing the acquisition of a new memory area on the main memory in response to a request from an application program; a free memory capacity calculation step for calculating the current free memory capacity on the main memory; memory acquisition possibility, which compares the acquisition memory capacity requested in the memory acquisition request stage with the free memory capacity calculated in the free memory capacity calculation stage and determines whether the requested capacity of memory can be acquired; a memory acquisition failure notification step for notifying the requesting application program that memory acquisition has failed if memory acquisition is determined to be impossible in the memory acquisition possibility determination step; A memory acquisition step in which the memory area is actually acquired if it is determined that the memory area can be acquired in the possibility determination step; and a memory acquisition step in which the free memory capacity on the main memory is restored after acquiring a new memory area in the memory acquisition step. a step of recalculating the free memory capacity; a warning determination step of determining whether the free memory capacity calculated in the step of recalculating the free memory capacity is less than or equal to a predetermined warning threshold; and the warning determination step. 1. A main memory management method comprising: a warning means for warning an operator that free memory capacity is low when it is determined that the remaining free memory capacity is below a warning threshold. (2) a memory acquisition request unit that instructs acquisition of a new memory area on the main memory in response to a request from an application program; a free memory capacity calculation unit that calculates the current capacity of free memory on the main memory; memory acquisition possibility, which compares the acquisition memory capacity requested by the memory acquisition request unit with the free memory capacity calculated by the free memory capacity calculation unit and determines whether the requested capacity of memory can be acquired; a determination unit; a memory acquisition failure notification unit that notifies a requesting application program that memory acquisition has failed when memory acquisition is determined to be impossible by the memory acquisition possibility determination unit; A memory acquisition unit that actually acquires the memory area when it is determined that the memory area can be acquired by the possibility determination unit, and a memory acquisition unit that regenerates the capacity of free memory on the main memory after acquiring a new memory area by the memory acquisition unit. a free memory capacity recalculation unit that calculates the free memory capacity; a warning determination unit that determines whether the free memory capacity calculated by the free memory capacity recalculation unit is less than or equal to a prespecified warning threshold; and the warning determination unit. 1. A main memory management device comprising: a warning unit that warns an operator that free memory capacity is low when the unit determines that the remaining memory capacity is below a warning threshold.