JP2560620B2 - Exclusive control device with time limit - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a time-limited exclusive control device in a computer system.

[0002]

2. Description of the Related Art A time-limited exclusive control device, that is, a control device that controls an exclusive control function, which is an exclusive use of shared resources, to be allowed only within a fixed time, has conventionally been equipped with an interval timer for measuring a time interval. The time control processing function used and the exclusive control processing function provided by the system are implemented as separate processing functions.

A conventional time-limited exclusive control device will be described with reference to FIG. In FIG. 2, when the process 22 running in the central processing unit 21 uses one of the shared resources (not shown) of the system with a time limit, first, the exclusive control processing function provided by the system is used exclusively. After acquiring the right, the interval timer control unit 23 is activated to register a specific time limit for using the shared resource. The interval timer control unit 23 activates the interval timer 24 from the time of registration, monitors the time limit, and after the time limit elapses, the interrupt processing control unit 26 notifies the time arrival notification destination 27 of the time by the interval timer runout processing procedure 25. Notify arrival.

The process 22 that registers the time limit and monopolizes one of the shared resources of the system always checks whether the time limit notification destination 27 has been notified of the arrival of the time limit, and When notified, or when the exclusive use of the shared resource is completed within the time limit, the exclusive control processing function of the system is activated to perform the exclusive use right release processing.

As described above, in the conventional time-limited exclusive control device, the process is activated each time the time control processing function and the exclusive control processing function are separate processing functions.

This makes the interval timer 24, which is the only one in the system, one independent function so that many processes can be used for various purposes.
Regardless of the purpose of use, the interval timer runout processing procedure 25 must execute necessary operations common to various applications. Therefore, a time arrival notification destination 27 is provided to notify the arrival of the time limit. is there. Exclusive control is only one of its purposes.

[0007]

The above-described conventional time-limited exclusive control device includes an exclusive control process for system resources,
Since the time control process is performed as a separate process,
When a process is interrupted between these two processes due to an abnormal operation of another process operating in the system, there is a drawback that the time-limited exclusive control does not function effectively.

This will be described with reference to FIG. FIG.
6 is a flowchart showing the operation of a conventional time-limited exclusive control device. In step 31, after the system performs the exclusive use right acquisition process at the request of a certain process, the process performs the time limit setting process on the interval timer to activate the time control process (step 32). While performing the process A using the shared resources of the system (step 33), the process constantly checks whether the time limit has been reached (step 34). When the time limit is reached (YES branch of step 34) or when the process A ends within the time limit (YES branch of step 35), the process activates the exclusive use right release process of the system (step 36). ) End the time-limited exclusive control.

When the process of the process requesting the exclusive use is interrupted in the section from the time t1 to the time t2 shown in FIG. 3, the monopolized state of the system resource is never released and the system operation is hindered. That is the problem.

An object of the present invention is to provide a time limit that does not result in the monopoly state of system resources not being released indefinitely if the time limit is reached even if the process of the process requesting exclusive use is interrupted. To provide an exclusive control device.

[0011]

According to a first aspect of the present invention, there is provided a time-limited exclusive control device, wherein a process which makes the request in response to one time-limited exclusive use request of a shared resource of the system is shared resource. Process control means for deciding whether to use the shared resource as a waiting process or a usage right acquisition process for the shared resource, a plurality of interval timers provided corresponding to the shared resource, and a usage request for the usage right acquisition process. Interval timer group control means for setting an exclusive use time limit required by the usage right acquisition process in the interval timer corresponding to the shared resource and monitoring the elapsed time, and reaching an exclusive use time limit required by the usage right acquisition process. the shared resource to store the corresponding processing procedure respond to the exclusive use time limit arrival of notifications from the interval timer group control means when Select the processing procedure corresponding to the notification and is configured to include an interrupt controller to be executed by the system in preference to others.

The exclusive control device with time limit of the second invention is
In the first invention, the shared resource when the exclusive use time limit is reached
The processing procedure corresponding to the source is characterized by being a time-limited exclusive use cancellation processing procedure corresponding to the usage management of the shared resource .

[0013]

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

FIG. 1 is a block diagram showing an embodiment of the time-limited exclusive control device of the present invention.

As shown in FIG. 1, the time-limited exclusive control apparatus of the present embodiment includes a central processing unit 1, a process 2 being executed by the central processing unit 1, and a process desiring to use a shared resource. A process state control unit 3 for performing state control,
A plurality of interval timers 5 to 8, an interval timer group control unit 4 that sets a time limit on these interval timers and monitors the arrival of the time limit, and an interrupt is registered in the central processing unit 1 when the time limit is reached. Processing procedure 1
It is configured to include an interrupt processing control unit 9 that causes the central processing unit 1 to preferentially execute the corresponding processing procedure of 0 to 13 and processes 14 to 15 in a use waiting state.

FIG. 4 is a flow chart showing the operation of the process state control section 3, FIG. 5 is a flow chart showing the operation of the interval timer group control section 4, and FIG. 6 is a flow chart showing the operation of the interrupt processing control section 9.

The operation of this embodiment will be described with reference to FIGS. 1 and 4 to 6.

The process 2 operating on the central processing unit 1 of the computer system adopting the multiple programming system allocates system shared resources such as a specific management table and peripheral devices exclusively to other processes. If you want to use it with a limitation, issue a time limit exclusion request command.

At this time, an identification name for uniquely identifying the system shared resource to be exclusively used, a time limit, and a processing procedure when the time limit is reached are specified. Operatein
CPU is the only system shared resource
Rather, the right to use various peripheral devices, the use of various files
Rights, data usage rights for operating system control
There are many types, and each usage right has its own method.
Since it is managed by
The processing procedure is different. For example, operating system
The data usage right for control is locked using the semaphore function.
Since this is the release process, the release process of the semaphore is
Peripheral management table for usage rights of various peripheral devices
Since the control data value of is used after being updated,
For example, the release processing is required.
Since the processing procedure is different, share the processing procedure when the time limit is reached
It must be specified according to the resource.

As shown in FIG. 4, the process state control unit 3 receives an exclusion request instruction (YES branch of step 41).
The state of the shared resource corresponding to the identification name is checked (step 42), and when this shared resource is being used by another process (YES branch of step 43), the process that issued the exclusion request instruction is waited for as a process waiting for use. When the shared resource is set to the state (step 44) and this shared resource is not being used by another process (NO branch of step 43), an exclusive use right is given to this shared resource to uniquely identify the system shared resource targeted for exclusive use. Then, the interval timer group control unit 4 is notified of the time limit and the processing procedure when the time limit is reached (step 45).

Upon receiving this notification, the interval timer group control unit 4 searches the interval timer 5 corresponding to the identification name as shown in FIG. 5 (step 51), sets the time limit given thereto, and sets the interval time. The value of the timer 5 is subtracted as time passes (step 53). Also,
Processing procedure 1 when the time limit is reached for the interrupt processing control unit 9
0 is registered (step 54).

The process 2, which has issued the time-limited exclusion request command, has acquired the exclusive use right of the system resource, and continues the processing without waiting for the use.

The process 2 which has acquired the exclusive use right
If the time limit exclusion release command is issued by specifying the identification name before the time limit is reached, the process state control unit 3 will
In response to this command (NO in step 41),
(Branch), the state of the shared resource corresponding to the identifier is checked (step 46), and if there is a process waiting for use in this shared resource (YES branch of step 47), it is judged as the exclusive use target requested by this process waiting for use. The interval timer group control unit 4 is notified of the identification name for uniquely identifying the system shared resource, the time limit, and the processing procedure when the time limit is reached (step 48).

When there is no process waiting for use in this shared resource (NO branch of step 47), the interval timer group controller 4 is notified of the reset of the corresponding interval timer and processing procedure (step 49), and the interval timer group controller. As shown in FIG. 5, reference numeral 4 resets the corresponding interval timer in step 57, notifies the interrupt processing control unit 9 of cancellation of the corresponding processing procedure, and responds to this by interrupt processing control unit 9 As shown in FIG. 6, in step 65, the registration of this processing procedure is canceled and the processing of the time-limited exclusion cancellation command is ended.

Process 2, which has acquired the exclusive use right,
If the corresponding interval timer value continues to be decremented before the time limit exclusion release command is issued and the time limit is reached (YES branch of step 55), a time limit reaching event occurs and the interval timer group control unit 4 The interruption processing control unit 9 is notified that the time limit has been reached (step 56).

In response to the notification that the time limit has been reached (YES branch of step 61), the interrupt process control unit 9 searches for the corresponding process procedure (step 62), and the process procedure when the time limit is reached is changed. The process is preferentially executed on the central processing unit 1 to finish the process when the time limit is reached.

The process at the time of reaching the time limit can be arbitrarily selected by the process, but as an example, there is a process of issuing a time limit exclusion cancellation command and returning to step 46.

As described above, in this embodiment, by integrating the time control function and the exclusive control function, even when the process of the process requesting the exclusive use is interrupted, the time limit is reached. Can avoid the deadlock without depending on the process requesting exclusive use, and can make more effective use of system resources.

[0029]

As described above, in the time-limited exclusive control device of the present invention, by integrating the time control function and the exclusive control function, the processing of the process requesting the exclusive use is interrupted. Even when the time limit is reached, even if the time limit is reached, the monopolized state of the system resources is not released and the system resources can be used more effectively.

[Brief description of drawings]

FIG. 1 is a block diagram showing one embodiment of a time-limited exclusive control device of the present invention.

FIG. 2 is a block diagram showing an example of a conventional time-limited exclusive control device.

FIG. 3 is a flowchart showing the operation of a conventional time-limited exclusive control device.

FIG. 4 is a flowchart showing the operation of the process state control unit 3.

FIG. 5 is a flowchart showing the operation of the interval timer group control unit 4.

FIG. 6 is a flowchart showing the operation of the interrupt processing control unit 9.

[Explanation of symbols]

1, 21 Central processing unit 2, 14, 15, 22 Process 3 Process state control unit 4 Interval timer group control unit 5-8, 24 Interval timer 9 Interrupt processing control unit 10-13 Processing procedure 23 Interval timer control unit 25 Interval Timer run-out processing procedure 27-hour arrival notification destination 31-36, 41-49, 51-57, 61-65
Flow chart steps

Claims (2)

(57) [Claims] 1. A process that has made a request in response to a time-limited exclusive use request for a shared resource possessed by the system is either a process waiting for use of the shared resource or a process for acquiring a right to use the shared resource. Requesting the usage right acquisition process to the process state control means, a plurality of interval timers provided corresponding to the shared resource, and the interval timer corresponding to the shared resource requested to be used by the usage right acquisition process. An interval timer group control means for setting an exclusive use time limit and monitoring the lapse of time, and storing a processing procedure corresponding to the shared resource when the exclusive use time limit required by the usage right acquisition process is stored and storing the interval timer group. In response to the notification that the exclusive use time limit has been reached from the control means, the processing procedure corresponding to the notification is selected to give priority to others. And an interrupt control means for causing the system to execute the system. 2. A shared resource when an exclusive use time limit is reached
2. The time-limited exclusive control device according to claim 1 , wherein the corresponding processing procedure is a time-limited exclusive use cancellation processing procedure corresponding to usage management of the shared resource .