JPH06214809A - Computer system - Google Patents

Abstract

PURPOSE:To effectively use a CPU and resources such as memories by preventing an unrequired process from being present on a main storage. CONSTITUTION:An unrequired process detecting part 14 detects a process which satisfies a prescribed condition in the processes set in idling states, or the process with an execution file name decided in advance as the unrequired process based on information in a process table 13, and the complusory completion of the unrequired process is performed by a process managing part 11. In such a case, a compulsorily completed process is automatically deleted from the memory 21 and the process table 13. Thereby, a state where only required processes are stored in the memory 21, and no unrequited process is present on the memory can be set. Therefore, it is possible to reduce the unrequired completion operation of the process by a user and the wasteful usage of the resources by the unrequired process.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a computer system, and more particularly to a computer system whose operation is controlled by a multi-process operating system (OS).

[0002]

2. Description of the Related Art In recent years, various multi-process (or multi-task) type OSs having a process management function for executing a plurality of processes in parallel have been developed.
In a computer using this type of OS, the number of processes that can exist in the main memory of the computer is determined by the number of process entries that can be stored in the process table.

Here, the process table is an array of structures that give one entry for each process, and this process table stores information necessary when the process is executed.

In the conventional multi-process OS, when the number of processes increases and the process table becomes full, it becomes impossible to create new processes. At this time, of the processes existing in the process table,
A new process can be created by finding and terminating a process that is not currently in use or does not need to exist, that is, an unnecessary process. Here, the unnecessary process is a process that has been idle for a long period of time or a process that does not need to be executed.

For example, in a conversational process,
If a user leaves a lot of processes and doesn't know where they left their seats, most of them are idle and can be said to be unnecessary processes.

When all the entries in the process table are filled up, there is no place to store the process information, and no more processes can be created. In such a case, the conventional OS sends a message to the user that the process cannot be created. Then, the user who receives the message searches for an unnecessary process to create a new process,
To finish.

Only the owner of the unnecessary process or the system administrator can terminate the unnecessary process. Therefore, when one user has many processes in the computer, another general user (not the system administrator) who owns only one process (login shell) tries to execute a new process and the process table is displayed. Even if you get the message that there is no room, you cannot run the new process forever because there is no process that can be terminated.

The existence of a process means that there is an entry corresponding to the process table and the execution program of the process is stored in the main memory. Therefore, when the main memory is full, swapping occurs when trying to execute a process that does not exist in the main memory at that time.

Swapping is a method for realizing virtual memory. In a virtual memory system, a virtual address is assigned to a main memory and a secondary memory to provide an environment in which a user using a computer can use it without being aware of the memory capacity.

FIG. 8 shows a specific example of swapping. When there is no memory space to be allocated to a new process in the main memory, the process (process 4) existing in the main memory is written to the secondary memory in order to allocate the memory space to the new process (process 6). Free space is created in the memory space (swap out).

At this time, the entry of the swapped-out process still exists in the process table.
Then, the process (process 6) swapped out to the secondary memory is read into the main memory (swap in).

In the virtual memory system using such a swapping system, the information of the swapped-out process is held in the process table, and the swapped-out process can be swapped in and executed at any time. Is configured.

However, in reality, the processes to be swapped out also include unnecessary processes. Since such an unnecessary process is not swapped in and is not executed again, its swapping is a useless operation. if,
If such swapping does not occur, CP for that
U can be assigned to other processes, and resources such as CPU and memory can be effectively used.

As described above, in the conventional OS, the unnecessary processes increase or do not perform the work of the user, and the existence of the unnecessary processes wastes resources such as CPU and memory. was there.

[0015]

Conventionally, when the process table becomes full, the user has to search for an unnecessary process and ask the owner of the process to terminate it, or there is an unnecessary process. This caused unnecessary use of memory and swapping.

The present invention has been made in view of the above circumstances, and provides a computer system in which unnecessary processes do not exist in the main memory and resources such as a CPU and a memory can be effectively used. With the goal.

[0017]

Means and Actions for Solving the Problems
In a computer system that can process multiple processes in parallel, a process table that holds information about multiple processes and the information in this process table are referenced to detect unnecessary processes that meet a specified condition from idle processes. The first feature of the present invention is to include an unnecessary process detecting unit for executing the unnecessary process and a forced ending unit for forcibly ending the unnecessary process detected by the unnecessary process detecting unit and deleting the unnecessary process from the main memory.

In this computer system, a process satisfying a predetermined condition among idle processes is detected as an unnecessary process based on the information in the process table, and the unnecessary process is forcibly terminated. In this case, the killed process is automatically deleted from the main memory. Therefore, only the necessary process is stored in the main memory, and the unnecessary process does not exist. Therefore, it is possible to reduce unnecessary process termination operations by the user and waste of resources by unnecessary processes.

Further, according to the present invention, in a computer system whose operation is controlled by a multi-process type operating system, a process table holding information of the plurality of processes, storing and deleting the process in a main memory, and a main memory. A memory management unit that executes a process move between the secondary storage and the secondary storage; a process management unit that controls execution and termination of the process; a process that refers to the process table and has no child process among idle processes; Alternatively, an idle process and an unnecessary process detecting unit that detects a process in an idle state as a child process of the process as an unnecessary process and instructs the process management unit to forcibly terminate the unnecessary process are provided. There are two characteristics.

In this computer system, according to the parent-child relationship of processes, not only one process but also
A plurality of related processes can be detected as unnecessary processes, and control can be performed so that the number of processes existing in the main memory becomes smaller.

[0021]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows the configuration of a computer system according to an embodiment of the present invention. The operation of this computer system is controlled by a multi-process type operating system, and in the figure, the parts particularly related to process management among the functions provided by the operating system are extracted and shown. .

The process management unit 11, the memory management unit 12,
Process table 13 and unnecessary process detector 14
Is included in the kernel of a multi-process operating system, and these are stored in the system area on the main memory and manage each process existing in the user space on the main memory. Here for simplicity,
A user space on the main memory in which various processes exist is shown as a memory 21.

The process management unit 11 executes a process.
It is for controlling termination, and CPU is assigned to a process to be executed, an entry in the process table 13 is operated, and it is checked whether or not a condition for activating the unnecessary process detection unit 14 is satisfied. . The memory management unit 12 stores the process in the memory 21 or performs swapping when there is a process having no place to store the process in the memory 21.

The process table 13 is an array of structures for storing process information. The process table 13 stores information such as process status, process parent-child relationship, idle time, and the like.

The unnecessary process detector 14 searches for an unnecessary process from all the processes existing in the process table 13. FIG. 2 shows some fields of the process table.

As shown in FIG. 2, the process table 13 includes a process identifier, a process state, a parent process name, and a process identifier for each of all generated processes (here, process 1 to process 9). Information such as child process name, execution file name, addle time, and pointer to memory is managed. Next, the forced termination operation of the unnecessary process in the embodiment of FIG. 1 will be described.

The example here is an example in which the forced termination operation is activated on the condition that the entry of the process table 13 is full out of several possible conditions.

The process management unit 11 uses the process table 1
When it is detected that there is no space in the process entry by referring to 3, a signal is sent to the unnecessary process detection unit 14.
Then, the unnecessary process detection unit 14 that has received the signal
Refers to the process information in the process table 13,
Find unwanted processes.

If there is an unnecessary process, a signal is sent to the process management section 11 so as to forcibly terminate the unnecessary process. Upon receiving the signal, the process management unit 11 sends a signal to the memory management unit 12 to release the memory area of the unnecessary process,
The entry of the unnecessary process is deleted from the process table 13. Then, the memory management unit 12 releases the memory area 21 used by the unnecessary process. Less than,
A method of implementing the unnecessary process detection unit 14 will be described.
There are the following three methods for realizing the unnecessary process detecting unit 14. The first method focuses on the parent-child relationship of processes. First, a process tree showing a parent-child relationship will be described with reference to FIG.

A process tree is a process in which circles (nodes) represent processes and branches connect the process parents and children. The parent-child relationship of a process means that a process can create a new process during its execution, so that the currently executing process is a parent and the created process is a child. In the process tree of FIG. 3, there is only one process that has no parent, and the other processes have only one parent process. Now, let's return to the first implementation method. FIG. 4 shows an algorithm of this realizing method.

Upon receiving the signal from the process management unit 11, the unnecessary process detection unit 14 first empties an unnecessary process list (not shown) (step S11), and then refers to the idle time field of the process table 13 to set an idle time. The process with the longest time is searched (step S12). Then, the process status field of the process table 13 is referenced to check whether the process is currently idle (step S13).

When not in the idle state, the unnecessary process detection unit 14 sends a signal to the process management unit 11 to forcibly terminate the process in the unnecessary process list (step S16). However, at this time, the unnecessary process list remains empty and no process is registered there. Therefore, forced termination processing is not performed.

On the other hand, if it is determined in step S13 that the process is idle, the process is stored in the unnecessary process list (step S14). Next, the field of the child process of the process table 13 is referred to, and it is checked whether or not the process has a child process (step S15).

If there is no child process, the unnecessary process detection unit 14 sends a signal to the process management unit 11 to forcibly terminate the process in the unnecessary process list (step S16). At this time, since the process is registered in the unnecessary process list, the forced termination process of the process is executed.

When the child process has a child process, the process state field corresponding to the child process in the process table 13 is referred to, and it is checked whether or not the child process is in the idle state (step S17). When the child process is in the idle state, the child process name is stored in the unnecessary process list (step S1).
4). Then, by referring to the child process field of the process table 13, it is checked whether or not the process has a child process (step S15).

If there is no child process, the unnecessary process detection unit 14 sends a signal to the process management unit 11 to forcibly terminate the process in the unnecessary process list (step S16).

At this time, since two processes are registered in the unnecessary process list, the forced termination process of those processes is executed. On the other hand, when it has a child process, the process of step S17 is performed.

As described above, in the first method, the states of all the processes existing in the process table 13 except the process having no parent process (process 1 in FIG. 3) are compared with the process states in the process table 13 and idle states. Look at the time field to find out and idle
A process (process 3 in FIG. 2) having the longest idle time is obtained from among the processes in 1), and the process is stored as an unnecessary process in the unnecessary process list.

Furthermore, a child process (see FIG. 2) is added to this process.
If there is a process 4) or a grandchild process, the state of those descendant processes is similarly checked. If all the descendant processes are idle, these descendant processes are also stored in the unnecessary process list, and a signal is sent to the process management unit 11 to forcibly terminate the process in the unnecessary process list. If any of the descendant processes is not idle, the process will not be killed.
In the state of FIG. 2, processes 3 and 4 are the processes that are killed first when the first method is applied. Next, with reference to the flowchart of FIG. 5, a second method of realizing the unnecessary process detection unit 14 will be described.

When receiving the signal from the process management unit 11, the unnecessary process detection unit 14 first refers to the field of the child process of the process table 13 of FIG. 2 and refers to the child processes 4, 5, 6, 8, and 9. The state of the process having no process is checked by referring to the state field of the process table, and the idle time of the process in the idle state (process 4, 5, 8, 9 in FIG. 2) is equal to or longer than a certain time (for example, 60 minutes). Is checked (steps S21 and S22).

If the idle time is longer than a certain time, a signal is sent to the process management unit 11 so as to forcibly terminate the process as an unnecessary process (step S23). In this case, the first process to be killed is process 4. Next, a third method of realizing the unnecessary process detection unit 14 will be described with reference to the flowchart of FIG.

When receiving the signal from the process management unit 11, the unnecessary process detection unit 14 first prepares a list (forced termination possible list, see FIG. 7) in which execution file names of processes that can be forcibly terminated are stored. The execution file names of all processes existing in the table 13 are checked by referring to the execution file name field of the process table 13, and the processes whose execution file names are included in the forcible termination list are stored in the unnecessary process list (step S31). ~ S33).

Then, a signal is sent to the process management section 11 to forcibly terminate the processes in the unnecessary process list. In this case, the process to be forcibly terminated first is process 9.

As described above, in this embodiment, based on the information in the process table 13, the unnecessary process detection unit 14 performs the process satisfying a predetermined condition among the processes in the idle state or the predetermined execution. The process having the file name is detected as an unnecessary process, and the unnecessary process is forcibly terminated by the process management unit 11.

In this case, the forcibly terminated process is automatically deleted from the memory 21 and the process table 13. Therefore, only the necessary process is stored in the memory 21, and the unnecessary process does not exist. Therefore, it is possible to reduce unnecessary process termination operations by the user and waste of resources by unnecessary processes.

[0047]

As described above, according to the present invention, since the OS detects and forcibly terminates the unnecessary process, the unnecessary operation of the user to terminate the unnecessary process and the wasteful use of the CPU and the memory by the unnecessary process are avoided. It is possible to reduce.

[Brief description of drawings]

FIG. 1 is a block diagram showing the configuration of a computer system according to an embodiment of the present invention.

FIG. 2 is a diagram showing an example of a process table provided in the computer system of the embodiment.

FIG. 3 is a diagram showing an example of a structure of a process tree in the computer system of the embodiment.

FIG. 4 is a flowchart showing a first operation example of an unnecessary process detection unit in the computer system of the same embodiment.

FIG. 5 is a flowchart showing a second operation example of the unnecessary process detection unit in the computer system of the same embodiment.

FIG. 6 is a flowchart showing a third operation example of the unnecessary process detection unit in the computer system of the same embodiment.

FIG. 7 is a diagram showing an example of a forced termination possible list in the computer system of the embodiment.

FIG. 8 is a diagram for explaining a conventional swapping operation.

[Explanation of symbols]

11 ... Process management unit, 12 ... Memory management unit, 13 ... Process table, 14 ... Unnecessary process detection unit, 21 ... Memory, 22 ... Secondary storage.

Claims (4)

[Claims] 1. In a computer system capable of processing a plurality of processes in parallel, a process table holding information of a plurality of processes, and by referring to the information of the process table, a predetermined condition is selected from among idle processes. A computer comprising: an unnecessary process detecting means for detecting an unnecessary process to be satisfied; and a forced ending means for forcibly ending the unnecessary process detected by the unnecessary process detecting means and deleting the unnecessary process from the main memory. system. 2. In a computer system whose operation is controlled by a multi-process operating system, a process table holding information of the plurality of processes, storing and deleting processes in a main memory, and a main memory and a secondary memory. Memory management means for performing process movement between processes, process management means for controlling execution and termination of processes, and a process that refers to the process table and has no child process among idle processes or idle processes A process and its child processes that are idle are detected as unnecessary processes,
A computer system comprising: an unnecessary process detecting means for instructing the process managing means to forcibly terminate the unnecessary process. 3. A computer system whose operation is controlled by a multi-process operating system, a process table holding information of the plurality of processes, storing and deleting of processes in a main memory, and a main memory and a secondary memory. Memory management means for executing process movement between processes, process management means for controlling execution and termination of processes, and a process having a predetermined execution file name by referring to the process table is detected as an unnecessary process,
A computer system comprising: an unnecessary process detecting means for instructing the process managing means to forcibly terminate the unnecessary process. 4. The computer system according to claim 1, wherein the unnecessary process detection means is activated when there is no free area in the process table.