JPH01220046A - Exclusive control method - Google Patents

Abstract

PURPOSE:To lighten the burden of a central processing unit concerned with exclusive control by reporting busy to a reference registration request when an object page is already registered and transmitting the interruption of busy-to- free to the central processing unit which reports the busy to the reference registration request when the registration of the page is canceled. CONSTITUTION:One exclusive controller 1 is provided for a computer system as a dedicated device to hold and control a table for the exclusive control of the page and connected to plural central processing units 2 by input/output interfaces 4. When each transaction requests reference and registration to the table for the exclusive control before a page access, when the object page is already registered, the busy is reported to the reference registration request and when the registration of the page is canceled, the interruption of the busy- to-free is generated to the central processing unit which reports the busy. Thus, it becomes unnecessary for the central processing units 2 to hold and control the table for the exclusive control and the burden of the central processing units is lightened.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is an exclusive!IJ# method comprising one or more central processing units and files and file storage devices shared by the central processing units. The present invention relates to a control method for preventing other transactions from accessing a file that is being processed by one transaction in a computer system.

[Conventional technology]

Exclusive control of shared files between multiple transactions is
Logically, it is executed as follows.

(1) An exclusive control table that is referenced before accessing a file is installed in the computer system, and files registered in the table are not accessed.

(2) If you want to process a file exclusively, register the target file in the exclusive control table above, enter the process after registration is completed, and delete the registration after the process is completed. 6. It is compared with the registered file, and if a matching file exists, the R recording is not completed.

There are the following two options as the unit of registration in the above-mentioned exclusive control table.

(i) File (it) A file device access unit (hereinafter referred to as a "page") that constitutes a file. Conventionally, the above-mentioned exclusive control table is placed on the main memory of the central processing unit, and the central processing unit was managed.

[Problem to be solved by the invention]

However, the above conventional technology has the following drawbacks.

(I) When the unit of registration in the exclusive control table is a file, the unit of exclusive control is large, so the process of matching with already registered files does not place a large load on the central processing unit, but it does require a file wait. Transactions will increase.

(II) If the unit of registration in the exclusive control table is a page, fewer transactions will have to wait for a file, but since there are many pages, matching with already registered files will place a heavy load on the central processing unit. Become.

(m) If there are multiple central processing units, it is necessary to refer to and update the exclusive control table through communication between the central processing units, resulting in an even heavier load on the central processing units.

The present invention has been made in view of the above-mentioned circumstances, and its purpose is to solve the above-mentioned drawbacks of the conventional technology, and to provide a system that can be shared by one or more central processing units and the central processing unit. In a computer system that has files and file storage devices, the load on the central processing unit related to exclusive control is reduced when the registration unit in the exclusive control table is a "page" which is the file device access unit that constitutes the file. The purpose of the present invention is to provide an exclusive control method that enables

[Means to solve the problem]

The above-mentioned object of the present invention is to provide an exclusive control method using an exclusive control table in a computer system having one or more central processing units, files and file storage devices shared by the central processing units; In addition to providing a table for each page, one exclusive control device is provided in the system as a dedicated device for holding and managing the exclusive control table, and the exclusive control device is connected to the central processing unit by an input/output interface.・Subsequently, each transaction makes a reference/registration request to the exclusive control table before accessing the page, and the reference/registration request is made to the exclusive control table.
The target page is accessed only when the registration request is completed, and at that time, the exclusive control device reports busy in response to the reference/registration request if the target page is already registered, and also When the registration is cancelled,
This is achieved by an exclusive control method characterized by notifying a busy-to-free interrupt to the central processing unit that has reported busy in response to the reference/registration request.

[Effect]

In the exclusive control method according to the present invention, one exclusive control device is provided in a computer system as a dedicated device for holding and managing a table for exclusive control of pages, and is connected to a central processing unit through an input/output interface. makes a reference/registration request to the above exclusive control table before accessing the page, and if the target page is already registered, reports the reference/registration request as busy, and
When the registration of the page is deleted, a "busy-to-free" interrupt is generated to the central processing unit that reported the busy status, so the central processing unit is required to maintain and manage the exclusive control table. This causes
This can lighten the load on the central processing unit.

〔Example〕

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

FIG. 2 is a system diagram of a computer system that is an embodiment of the present invention. As shown in FIG. It is connected to the device 3 and the single exclusive control device 1 . The file device 3 has a single or multiple central processing bags! Files shared among multiple transactions processed by i2 are stored in page units.

FIG. 3 shows a specific example of the configuration of the exclusive control device 1. The exclusive control device 1 shown in this embodiment has a memory section 13. A central processing unit interface section 12 that communicates with each central processing unit. It consists of a common control section 11 that manages exclusive control tables and performs overall control.

FIG. 4 shows an example of the configuration of the exclusive control table. As shown in the figure, each entry in the exclusive control table is composed of the following columns.

(1) First column (21): Page name (2) Second column (22): Central processing unit number that registered the page name (3) Third column (23): Since the page name was registered List of central processing unit numbers that have made reference/registration access to the page The exclusive control operation in this embodiment configured as described above will be described below with reference to the processing flowchart shown in FIG. Figure 1(a) shows the processing on the CPU side, and Figure 1(b) shows the processing on the CPU side.
) indicates processing on the exclusive control device side.

Before each transaction accesses a page, an exclusive control table to be referenced is first installed in the exclusive control device.

First, an outline of the operation will be explained based on FIG. 1(a). When each transaction accesses a page, as shown in step 41, it first accesses the exclusive control device and checks whether the target page name is registered in the exclusive control table. In the case of this example, I
The OD address is constant, and the access type includes reference/
There are two types: reference and registration. If the target page name is registered in the exclusive control table, the exclusive control device reports busy in response to the access request. If the target page name is not registered, the access request ends normally. Only when the process ends normally, the target page is accessed as shown in step 43.

When the exclusive processing of a page is completed, each transaction accesses the exclusive control device as shown in step 45 in order to delete the corresponding page name from the exclusive control table. At this time, the exclusive control device issues a busy-to-free interrupt to the central processing unit that attempts to refer to or register the page name, as will be described later. In the central processing unit where busy-to-free interrupts have increased,
As shown in step 46, the transaction that has been kept waiting is determined and its processing is executed.

Hereinafter, the details of the operation of the exclusive control device will be explained based on FIG. 1(b). When the exclusive control device receives access,
If the type is determined (step 5o), the process shown in steps 51 to 54 is performed if it is a reference/registration request, steps 55 to 59 if it is a reference request, and steps 60 to 62 if it is a deletion request.

That is, each transaction accesses the exclusive control device and registers the target page name in the exclusive control table.

At the time of registration, the exclusive control device checks the already registered page name in the exclusive control table (step 51), and if there is no matching page name (step 52),
The target page name and registered CPU number are registered in the exclusive control table, and the access is normally terminated (step 53.
54). When the registration access ends normally, exclusive processing of the page begins.

At the time of reference, if a matching page name exists (step 56), the access waiting CP is stored in the exclusive control table.
The corresponding CPU is placed in the U number queue as shown in Figure 4.
Check if the number is registered or not Step 5
7) If it is not registered, register it (Step 5)
8), return busy for access (step 5)
9). Furthermore, if the target page name exists, the reference request ends normally (step 54). When the reference access ends normally, exclusive processing of the page begins.

When each transaction finishes exclusive processing of a page, it accesses the exclusive control device, and the exclusive control device deletes the corresponding page name from the exclusive control table in step 62. At this time, the exclusive control device raises a busy-to-free interrupt as shown in step 61 to the fault processing device that attempted to refer to or register the page name. As mentioned above, when a busy-to-free interrupt occurs, the central processing unit determines the transaction that has been kept waiting, and executes the transaction.

According to the embodiment described above, the load of exclusive control can be reduced from the central processing unit.6 FIG. 5 is a diagram showing an example of the configuration of an exclusive control table used in the second embodiment of the present invention. What is the difference between the exclusive control table shown in this embodiment and the exclusive control table of the first embodiment shown in FIG.

In the central processing unit where the busy-to-free interrupt occurs, the contents are as follows in order to facilitate the process of determining the transaction that is attempting to access the available page (has been kept waiting). This is what has been changed.

(1) First column (31): Page name (2) Second column (32): Central processing unit number that registered the page name (3) Third column (33): When the page name was registered Used device address (IOD number) (4) Fourth column (34): Central processing unit number that accessed the page for reference/registration after the page name was registered, and the number used at that time FIG. 6 is a processing flowchart showing the operation of the second embodiment, and the same numbers are used for the same processing steps as in FIG. 1 shown above. Similar processing steps (those using IOD numbers) are shown with the same number appended with a.

In this embodiment, the exclusive control device can be accessed using a plurality of IOD numbers, and the IOD number is used as an identification code for each transaction. Therefore, this is shown in the first embodiment. The IOD number when reporting the busy-to-free interrupt in step 61 is:
The IOD number can be used as an identification code in the process (step 46a) of determining which transaction corresponds to the IOD number of the previous access. This IOD number is
It is always used as an input/output interface when accessing the exclusive control device and interrupting from the exclusive control device, and is characterized in that there is no need to send or receive a special identification code.

FIG. 7 shows an example of the configuration of the memory unit 13 for speeding up the process of determining whether or not the reference/registration page has already been registered in steps 52 and 56 in the above-described embodiment. That is, in the above embodiment, the process of determining whether the reference/registration page name has already been registered is performed as follows:
Although it is assumed that this processing is performed using a method such as hashing or binary search, this processing often takes time, so an example is shown in which this processing is performed at high speed using hardware.

In FIG. 7, 200 is an associative memory (Content Address Memory,
CAM), and consists of a page name storage area 221 in which the page name 121 is stored and an entry valid display bit storage area 220. 201 is a CAM match signal 208
202 is a CAM access register, 203 is an address decoder, and 205 is a memory register.
204 is a RAM, and columns 2 to 4 (32
~34) storage areas 222-224. Note that 210 is a mismatch signal line that is output when there is no matching entry when searching for a match in CAM;
13 is an entry signal for requesting the registration of the CPU number and ○D number, 214 is the CPU number and ○D number that requested access.
Showing number entry signal. 206.207.2
12 is a data line.

In this embodiment, the basic procedure is the same as in each of the above-mentioned embodiments, except for step 52.5 in the above-mentioned embodiments.
The process of determining whether or not the reference/registration page has already been registered in step 6 can be performed as follows. That is, the name of the referenced/registered page is entered in the CAM access register 202, and a match search is performed in the CAM 200. Thereby, using the parallel processing capability inherent in the CAM 200, it is possible to easily perform a match search with registered page names.

〔Effect of the invention〕

As explained in detail above, according to the present invention, an exclusive control method using an exclusive control table in a computer system having one or more central processing units, files and file storage devices shared by the central processing units The exclusive control table is provided for each page, and one exclusive control device is provided in the system as a dedicated device for holding and managing the exclusive control table,
The exclusive control device is connected to the central processing unit through an input/output interface, and each transaction requests reference/registration to the exclusive control table before page access, and is processed only when the reference/registration request is completed. When accessing a page, the exclusive control device reports busy in response to a reference/registration request if the target page is already registered, and if the page is unregistered, the exclusive control device Since a busy-to-free interrupt is notified to the central processing unit that has reported busy in response to a reference/registration request, exclusive control can reduce the load on the central processing unit related to exclusive control in the computer system. This method has the remarkable effect of realizing the method.

In addition to the above exclusive control method, by using the device address used when each transaction accesses the exclusive control device as the identification code of the transaction, the page that is being accessed can be accessed exclusively by other transactions. If it is used, when the exclusive use by the other transaction is canceled, an interrupt will be generated to that effect, and the corresponding transaction can be determined using the device address of the interrupt as an identification code, and the central processing unit Another effect is that the load can be further reduced.

Furthermore, as other effects, the exclusive control device has an input/output interface connection, so it can be connected to different models and multiple central processing units, and communication between central processing units is improved in exclusive control that spans multiple central processing units. For example, it is unnecessary.

[Brief explanation of the drawing]

FIG. 1 is a processing flowchart showing an embodiment of the present invention;
FIG. 2 is a system diagram showing the computer system of the embodiment, FIG. 3 is a diagram showing a specific configuration example of the exclusive control device, and FIG.
5 is a diagram showing a configuration example of an exclusive control table, FIG. 6 is a processing flowchart showing another embodiment, and FIG. 7 is a configuration diagram showing an embodiment in which part of the processing is performed by hardware. It is. 1: exclusive control device, 2: central processing unit, 3: file device, 4: input/output interface device, 11: common control unit, 12: central processing unit interface unit, 13: memory unit, 20Q: CAM. Patent applicant Nippon Telegraph and Telephone Corporation

Claims (2)

[Claims] (1) In an exclusive control method using an exclusive control table in a computer system having one or more central processing units, files and file storage devices shared by the central processing units, the exclusive control table is The file device access unit that makes up the file (
one exclusive control device is provided in the system as a dedicated device for holding and managing the exclusive control table, and the exclusive control device is connected to the central processing unit by an input/output interface, Each transaction makes a reference/registration request to the exclusive control table before accessing the page, and accesses the target page only when the reference/registration request is completed.
The exclusive control device reports busy in response to the reference/registration request when the target page is already registered, and reports busy in response to the reference/registration request when the registration of the page is deleted. An exclusive control method characterized by notifying a central processing unit of a busy-to-free interrupt. (2) The exclusive control device can be accessed using a plurality of device addresses, and the device address is used as an identification code for each transaction, and a transaction can be referenced to the exclusive control table. Claim 1, characterized in that the device address of the busy-to-free interrupt after the registration request access is busy is used as an identification code to determine the transaction in which the reference/registration request is awaited. Exclusive control method described in section.