JP3603671B2 - Data sharing management device and data sharing management method - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a data sharing management device and a data sharing management method, in particular, an exclusive lock operation in which only a single process can use a shared resource, and a shared lock operation in which a plurality of processes can simultaneously use a shared resource. The present invention relates to a data sharing management device and a data sharing management method that execute while detecting a resource deadlock.
[0002]
[Prior art]
In a conventional data sharing management device, when a process having a data sharing management device accesses a shared resource, when a shared lock or an exclusive lock is applied, the shared resource or the exclusive lock is already locked when the lock fails. A deadlock was detected from the shared resources acquired by the process and the shared resources that the process is waiting to use. On the other hand, other conventional data sharing management devices lock reservations in advance on all shared resources to be used.
As a similar data sharing management device, there is known a device disclosed in Japanese Patent Application Laid-Open No. 1-120636.
[0003]
[Problems to be solved by the invention]
The conventional data sharing management device described above has the following problems.
The problem with the former method is that when evaluating the matching of locked shared resources, there is a problem that the processing time increases as the number of shared processes increases. The latter data sharing management device has a problem in that it is necessary to reserve all of the shared resources used by the user in advance, which complicates the processing configuration.
[0004]
Further, in the system disclosed in Japanese Patent Application Laid-Open No. 1-120636, process wait management is not performed because process group management and process wait management are not performed for deadlock detection, deadlock advance detection, and deadlock release control. Could not be implemented.
[0005]
The present invention has been made in view of the above problems, and can detect the occurrence of a deadlock without scanning a locked shared resource even when the operation of an exclusive lock or a shared lock fails. It is an object of the present invention to provide a possible data sharing management device and a data sharing management method.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, an invention according to claim 1 is a data sharing management device that accesses a shared resource when a plurality of processes operate and each process uses a page of the shared resource. process, a lock detecting means for detecting a lock by any process for the shared resources accessed manages the respective process of locking the same shared resource as a process group, locked shared resources, lock and process self In the case of a process group to which the group belongs, a shared resource state detecting means for detecting a deadlock is provided.
[0007]
In the invention according to claim 1 configured as described above, the data sharing management device accesses a shared resource when a plurality of processes operate and each process uses a page of the shared resource. When accessing, lock on shared resources. As described above, when using a shared resource in an environment where a plurality of processes operate at the same time, a deadlock may occur.
[0008]
Therefore, each process detects a lock by an arbitrary process on the shared resource accessed by the lock detection unit.
Here, if the shared resource is locked and the locked process is the process group to which it belongs, the shared resource state detecting means detects deadlock.
[0009]
That is, the process group is managed by the shared resource state detecting means, and a deadlock is detected based on whether or not the process which has locked the shared resource belongs to the process group.
[0010]
As a preferred processing method when a shared resource is locked by another process in a state of no deadlock, the invention according to claim 2 is the data sharing management according to claim 1. In the apparatus, the shared resource status detecting means may add the own process to a process group to which the process locking the shared resource belongs, if the process locking the shared resource is not the process group to which the process belongs. There is.
Further, according to a third aspect of the present invention, in the data sharing management device according to the first or second aspect, the lock is an exclusive lock or a shared lock, and the data sharing management device The configuration includes a lock type identification unit that identifies whether the type is an exclusive lock or a shared lock.
An exclusive lock is used when data is to be written to a shared resource and when it is necessary to ensure data consistency between processes. For example, when each process writes data to a shared resource, an exclusive lock is first placed on the shared resource, access to the shared resource from other processes is prohibited, and when the data is written, the exclusive lock is released. Make the shared resources accessible.
On the other hand, the shared lock indicates a state in which each process can simultaneously access a shared resource, and is used particularly in a read process in which there is no problem in data consistency.
[0011]
According to a fourth aspect of the present invention, as a preferred processing method when an exclusive lock is held on a shared resource by another process in a state where the state is not a deadlock state, the data sharing according to the third aspect is described. in the management apparatus, the shared resource state detecting means, if the process that is exclusive lock the shared resource is not a process of the process group of its own belongs, is configured so as to access to shared resources of its own process in a standby state.
[0012]
In the invention according to Claim 4 as constructed above, the shared resource state detection means, if the process that is exclusive lock the shared resource is not a process of the process group of its own belonging, access to the shared resources of its own process To the standby state. By setting the standby state, when the exclusive lock is released by the process that is in the exclusive lock state, the shared resource can be exclusively locked by the own process immediately.
[0013]
According to a fifth aspect of the present invention, in the data sharing management device according to any one of the third and fourth aspects, the lock type identification unit determines that the detected lock is a shared lock for a shared resource other than the own process. When the shared resource status detection means identifies that a process other than the own process is designated as the mode change permitted process of the process group to which the own process belongs, the shared resource state detecting means is configured to detect a deadlock.
[0014]
In the invention according to claim 5 , the lock detecting means detects a lock on the shared resource, and the lock type identifying means detects the lock on the shared resource other than the own process. If the process other than the own process is designated as the mode change permission process of the process group to which the own process belongs, the shared resource state detecting means detects the deadlock.
[0015]
Further, according to a sixth aspect of the present invention, in the data sharing management device according to the fifth aspect , the shared resource state detecting means determines whether the mode change permission process of the process group to which the own process belongs is not specified. Is set as a mode change permission process, and a standby state is set.
[0016]
In the invention according to claim 6 configured as described above, the shared resource status detecting means sets the own process as the mode change permission process when the process change permission process of the process group to which the own process belongs is not specified. As a result, the own process enters a standby state for the shared resource.
[0017]
Further, according to a seventh aspect of the present invention, in the data sharing management device according to any one of the third to sixth aspects, the shared resource state detecting means acquires a shared resource locked by the own process, When the shared lock is being applied to all the shared resources and the shared lock is detected by only the own process, the exclusive lock process is released from the standby state.
[0018]
In the invention according to claim 7 configured as described above, the shared resource state detecting means acquires the locked shared resource of the own process, and performs the shared lock on all the shared resources. When the lock is detected by the own process only, the waiting state of the exclusive lock process is released.
[0019]
As described above, when a plurality of processes operate and each process uses the page of the shared resource, the method of accessing the shared resource does not necessarily need to be limited to a substantial device, and also functions as the method. That is easy to understand. For this reason, the invention according to claim 8 is a data sharing management method for accessing a shared resource when a plurality of processes operate and each process uses a page of the shared resource. A lock detection step for detecting the lock of an arbitrary shared resource by a given process, and managing each process that locks the same shared resource as a process group, while the shared resource is locked and the process to which the locking process belongs belongs. In the case of a group, a shared resource state detecting step of detecting a deadlock is provided.
In other words, there is no difference that the present invention is not necessarily limited to a substantial device and is effective as a method.
[0020]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a block diagram showing a configuration of a data sharing management program according to an embodiment of the present invention.
In the figure, a data sharing management program A is included in each process operating on a computer, and includes a page state management module 100, a lock process management module 110, a process group management module 120, an inter-process state management And a module 130.
[0021]
Each process runs on a basic program that runs on a computer, and is stored on a hard disk or a shared memory that is a predetermined divided area developed on a memory, which is a shared resource on the computer. Files and other shared resources are mutually accessible.
[0022]
In the present embodiment, the concept of “page” is used as a shared resource such as the above-described shared memory and file, and each process P applies an exclusive lock or a shared lock to the “page” to perform predetermined data processing. Think about when to do it.
[0023]
Here, the exclusive lock is used when writing data to a “page” or the like and when it is necessary to ensure data consistency between processes. For example, when each process writes data “A” to page P, first, it locks page P exclusively, prohibits other processes from accessing page P, and writes data “A”. When the writing is completed, the exclusive lock is released, and another process can access the page P.
On the other hand, the shared lock indicates a state in which each process can simultaneously access the page P, and is used particularly in a read process in which there is no problem in data consistency.
[0024]
Here, as shown in FIG. 2, the page state management module 100 includes a lock determination module 101 and a lock type determination module 102. The lock determination module 101 detects whether a page of a shared resource to be accessed is locked. When the lock determination module 102 detects a lock on the page, the lock type determination module 102 identifies the type of the lock. That is, it is determined whether the lock is an exclusive lock or a shared lock.
[0025]
As shown in FIG. 3, the lock process management module 110 includes a lock process determination module 111 and a standby process determination module 112.
The lock process determination module 111 executes a process of storing a process that has locked a page and the number thereof. Further, the standby process determination module 112 executes a process of storing a process that has failed in locking a page and is in a standby state.
[0026]
The process group management module 120 executes a process of storing the processes belonging to the process group that locks the page of the shared resource. Then, the inter-process standby management module 130 executes a process of referring to the standby process list and storing the process that is waiting to use the shared resource.
[0027]
Next, the operation of each of the modules 100 to 130 will be described in detail with reference to the flowcharts of FIGS. 4, 5, 6, and 7.
First, the operation at the time of executing the shared lock, which is the first operation of the present embodiment, will be described with reference to FIG.
In the figure, when the page state management module 100 of the process detects either an exclusive lock or a shared lock on the page P of the shared resource to be accessed by the lock determination module 101, the lock type determination module 102 It identifies whether the lock on page P is an exclusive lock or a shared lock. Here, when it is identified that the page P is exclusively locked (step A1), the lock process management module 110 of the process uses the lock process determination module 111 to identify the process group that holds the exclusive lock. get.
[0028]
The lock process management module 110 determines whether the acquired process group is the same as the process number of its own process. If they are the same (step A2) and the process group that has exclusively locked page P is in its own standby process list (step A3), it is determined to be deadlocked (step A4). ).
[0029]
On the other hand, if it is not in its own standby process list, its own process is added to its own standby process list that exclusively locks page P (step A7). If the process group is different from the process number, the own process is added to the process group of the process (step A6), and further, the own process is added to the waiting process list of the process that exclusively locks the page P.
[0030]
If the page P is already locked (step A8), the standby process determination module 112 acquires a process waiting for the page P. Here, when the process group of the waiting process is the same as the process number of the own process (step A9), and the own process number is included in the waiting process list of the process waiting for page P. In (Step A10), a deadlock is determined (Step A11).
[0031]
On the other hand, if the own process number is not included in the waiting process list of the process waiting for page P, the process waiting for page P is added to the waiting process list of the own process (step A12).
If the process group of the waiting process is different from the process number of the own process, the own process is added to the process group of the process (step A13). (Step A12 ).
[0032]
Next, the operation at the time of executing the exclusive lock, which is the second operation of the present embodiment, will be described with reference to FIG.
In the figure, when the lock of the page P is detected by the lock determination module 101 (step A1), a process that has already locked the page P is acquired by the lock process determination module 111. The process group of the acquired process is compared with the process number of the own process. If the process numbers are the same (step A2), the process locking the page P enters the standby process list of the own process. If there is (Step A3), a deadlock is determined (Step A4).
[0033]
If the process is not included in the standby process list, the own process is added to the standby process list of the process locking the page P (step A5).
Further, when the process number is different from the process number, the own process is added to the process group of the corresponding process (step A6), and further, the own process is added to the standby process list of the process that locks the page P.
[0034]
Next, with reference to FIG. 6, a description will be given of an operation at the time of executing the lock state switching from the shared lock to the exclusive lock, which is the third operation of the present embodiment.
In the figure, when the lock process determination module 111 detects a shared lock by a process other than the subject process (step A1), a process other than the subject process is designated as the mode change permission process in the process group to which the subject process belongs (step A2). ), A deadlock is determined (step A3).
On the other hand, if nothing is specified, the process is set to the mode change permission process and put into a standby state (step A4). If there is no other locked process, the process switches between the exclusive lock and the locked state (step A5).
[0035]
The operation at the time of executing the lock release, which is the fourth operation of the present embodiment, will be described with reference to FIG.
In the figure, the page P locked by the own process is acquired by the lock process determination module 111 (step A1). Here, if the shared lock is being performed on all the pages P (step A2), the lock process determination module 111 detects that the lock on the page P is a lock by only the own process (step A3), and To release the wait of the process waiting for the exclusive lock (step A4).
[0036]
If there is another locked process and the process is a mode change permission process (step A5), the process is switched to an exclusive lock (step A6). On the other hand, when the page P is exclusively locked, the standby state of the process in the lock standby state is released (step A7). Here, if the released process is in the standby state with the shared lock (step A8), the standby state of all other processes that are in the standby state with the shared lock is released (step A9). After that, the process list of the own process is cleared and the process group is renumbered (step A10).
[0037]
In this way, the process management module 120 manages each process that locks the page P, which is the shared resource to be accessed, as a process group, and manages the standby state of each process in the shared resource, so that the deadline before access is obtained. In addition to collecting information for detecting a lock, it is possible to detect the occurrence of a deadlock without scanning a page that is exclusively locked when an exclusive lock or a shared lock fails.
[0038]
【The invention's effect】
As described above, the present invention manages each process that locks a shared resource in a process management device as a process group, and manages the standby state of each process in a shared resource to detect a deadlock before accessing. Gather information to do. Further, it is possible to provide a data sharing management device capable of detecting occurrence of a deadlock without scanning a shared resource locked exclusively when an exclusive lock or a shared lock fails.
According to the second aspect of the present invention, when the accessed shared resource is not a deadlock, by setting the standby state, the exclusive lock can be immediately acquired when the exclusive lock by another process is released. Will be possible.
Further, according to the third aspect of the present invention, it is possible to detect a deadlock by specifying a mode change permission process.
[0039]
Furthermore, according to the invention of claim 4, it is possible to set the mode change permission process in the standby state according to the specified mode.
Further, according to the invention according to claim 5, it is possible to release the waiting state of the process waiting for the exclusive lock.
Further, according to the invention of claim 6, each process that locks the shared resource in the process management device is managed as a process group, and the standby state of each process in the shared resource is managed, so that the deadline before access is obtained. Gather information to detect locks. Further, it is possible to provide a data sharing management method capable of detecting occurrence of a deadlock without scanning a shared resource locked exclusively when an exclusive lock or a shared lock fails.
[Brief description of the drawings]
FIG. 1 is a block diagram of a data sharing management module included in each process according to an embodiment of the present invention.
FIG. 2 is a block diagram illustrating a configuration of a page state management module.
FIG. 3 is a block diagram showing a configuration of a lock process management module.
FIG. 4 is a flowchart showing an operation at the time of executing a shared lock, which is a first operation of the embodiment.
FIG. 5 is a flowchart showing an operation at the time of executing an exclusive lock, which is a second operation of the embodiment.
FIG. 6 is a flowchart illustrating an operation at the time of executing a lock state switch from a shared lock to an exclusive lock, which is a third operation according to the embodiment.
FIG. 7 is a flowchart showing an operation at the time of executing lock release, which is a fourth operation of the embodiment.
[Explanation of symbols]
100 lock state management module 110 lock process management module 120 process group management module 130 inter-process management module

Claims (8)

A data sharing management device that accesses a shared resource when a plurality of processes operate and each process uses a page of the shared resource,
Each process includes: a lock detecting unit that detects a lock on an accessed shared resource by an arbitrary process;
A process for managing each process that locks the same shared resource as a process group, and a shared resource state detecting means for detecting a deadlock when the shared resource is locked and the locking process is a process group to which the process belongs. A data sharing management device. The data sharing management device according to claim 1,
The shared resource state detecting means adds the own process to the process group to which the process locking the shared resource belongs, when the process locking the shared resource is not the process group to which the process belongs. Data sharing management device. In the data sharing management device according to claim 1 or 2,
The lock is an exclusive lock or a shared lock,
The data sharing management device, wherein the data sharing management device includes a lock type identification unit that identifies whether the detected lock type is an exclusive lock or a shared lock. The data sharing management device according to claim 3 ,
The shared resource state detecting means, if the process that is exclusive lock the shared resource is not a process group of its own belonging, data sharing management apparatus characterized by access to shared resources of its own process in a standby state. In the data sharing management device according to claim 3 or 4 ,
When the lock type identifying means identifies that the detected lock is a shared lock for a shared resource other than the own process, the shared resource state detecting means sets the own process as a mode change permission process of the process group to which the own process belongs. A data sharing management device, wherein a deadlock is detected when a process other than is specified. The data sharing management device according to claim 5 ,
The data sharing management device, wherein the shared resource state detection means sets the own process as a mode change permission process and sets a standby state when there is no designation as a mode change permission process of a process group to which the own process belongs. In the data sharing management device according to any one of claims 3 to 6 ,
The shared resource state detecting means acquires a shared resource locked by the own process, and detects that the shared lock is being applied to all the shared resources and that the shared lock is exclusively performed by the own process. A data sharing management device, which releases the standby state of the process. A data sharing management method for accessing a shared resource when a plurality of processes operate and each process uses a page of the shared resource,
Each process includes a lock detection step of detecting a lock on the accessed shared resource by an arbitrary process;
A process for managing each process that locks the same shared resource as a process group, and a shared resource state detecting step for detecting a deadlock when the shared resource is locked and the locked process is a process group to which the process belongs. A data sharing management method.

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