JP2015075871A - Exclusive control program, information processing apparatus, and exclusive control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect deadlock efficiently.SOLUTION: When a first execution entity has an exclusive access right to an information resource, a second execution entity having tried to acquire the exclusive access right determines whether the entity has acquired the exclusive access right before a predetermined timing. When it is determined that the entity has not acquired the right before the predetermined timing, each of execution entities including the first and second execution entities tries to acquire at least one of the other exclusive access rights, excluding the exclusive access right already acquired, out of the exclusive access rights already acquired by the above execution entities. It is determined whether each of the exclusive access rights acquired by the execution entities is in standby to be acquired by at least one of the execution entities. When the standby state is determined, information processing is determined to be suspended in the process of execution.

Description

  The present invention relates to an exclusive control program, an information processing apparatus, and an exclusive control method, and more particularly to an efficient deadlock detection method.

  Usually, in an operating system installed and used in an information processing apparatus such as a PC (Personal Computer), a server, or an image forming apparatus, a plurality of execution entities that execute information processing such as processes, threads, and tasks are simultaneously the same. The exclusive control function is installed to avoid accessing the information resources. Here, the information resource is an element such as data used when the execution subject executes processing, or a special memory area commonly used when the execution subject executes processing.

  With this exclusive control function, the operating system can control only a specific execution entity to access the information resource exclusively, and a plurality of execution entities can rewrite the same data at the same time. Matching can be prevented.

  In an operating system equipped with such an exclusive control function, an access occupancy right called a lock is linked in advance to an information resource to be exclusively accessed from the execution subject. In such an operating system, when each executing entity accesses the information resource, each executing entity tries to acquire the lock, and only the executing entity that can acquire the lock has the information. The resource can be accessed.

  At this time, another execution entity that could not acquire the lock waits until the execution entity that has successfully acquired the lock and has accessed the information resource completes access to the information resource and releases the lock. It will be. Thereafter, the executing entity that has completed access to the information resource releases the lock, so that another executing entity waiting to acquire the lock can acquire the lock.

  With such a lock function, in a normal operating system, only a specific execution entity accesses the information resource exclusively, thereby preventing multiple execution entities from accessing the same information resource at the same time. It is possible to prevent the inconsistency from occurring.

  Incidentally, it is known that a malfunction called deadlock occurs in an operating system equipped with such a lock function. A deadlock occurs in a series of processes in which each execution entity does not complete processing until the lock acquired by the other execution entity is released and the lock is acquired. Are waiting for the other party to release the lock, and the process stops.

  For example, the execution entity α that completes the processing by acquiring the lock b associated with the information resource B after the access to the information resource A is completed, and the information resource A after the access to the information resource B is completed. It is assumed that the execution subject β that completes the processing by acquiring the lock a linked to Executes the processing in parallel. In such a case, first, the executing entity α exclusively accesses the information resource A, and the executing entity β exclusively accesses the information resource B.

  When execution entity α and execution entity β complete access to information resource A and information resource B, respectively, they next attempt to acquire lock b and lock a, respectively, but the locks acquired by each other are released. That is, the execution subject α waits for the release of the lock b and the execution subject β waits for the release of the lock α, both of which stop processing. Such a deadlock often depends on the processing timing of each execution subject and occurs even if there is no failure in the execution subject or information resource.

  Therefore, a deadlock detection method for detecting the occurrence of a deadlock by executing a deadlock detection process described later every time the execution subject tries to acquire a lock has been disclosed (for example, see Patent Document 1). ). When detecting the occurrence of a deadlock by such a deadlock detection method, the operating system loops in a directed graph configured by indicating the lock acquisition status and the acquisition wait status by the execution subject with arrows having directions. The deadlock detection process of detecting the occurrence of a deadlock by determining whether or not is formed is executed.

  For example, when the deadlock for the execution subject α and the execution subject β is taken as an example, “the execution subject α has acquired the lock a and is waiting to acquire the lock b, and the execution subject β has the lock b. And is in a state of waiting for acquisition of lock a ”. Therefore, in such a case, a loop “execution subject α → lock a → execution subject β → lock b → execution subject α” is formed in the directed graph. Here, the arrow from the execution subject to the lock indicates that the execution subject at the arrow origin has acquired the lock at the arrow destination, and the arrow from the lock to the execution subject indicates that the execution subject at the arrow destination is the lock at the arrow origin. Represents waiting for acquisition.

  When a loop is formed in the directed graph in this way, the operating system detects that a deadlock has occurred in the deadlock detection process.

  However, in such a deadlock detection method, the operating system executes the deadlock detection process every time the execution subject tries to acquire the lock, so that there is a problem that the deadlock detection efficiency is low.

  In addition, in such a deadlock detection method, the operating system allows a large number of execution entities such as hundreds or thousands to execute processing in parallel, so that these execution entities acquire one lock. Even when trying, the deadlock detection process is executed every time the execution subject tries to acquire the lock, and thus there is a problem that the efficiency of deadlock detection is even worse.

  This problem is not limited to the operating system installed and used in the information processing apparatus, and any program that allows multiple execution entities to access the same multiple information resources. It is a problem that can occur.

  An object of the present invention is to efficiently detect a deadlock.

  In order to solve the above problem, one of the execution entities that attempted to acquire an access exclusive right that is a right to exclusively access information resources that can be accessed in common by a plurality of execution entities that execute information processing. The execution occupancy right is acquired only by the execution entity, and when the access to the information resource from the one execution entity is completed, the access occupancy right is released by the one execution entity. An exclusive control program for controlling so that only the executing entity exclusively accesses the information resource, and after the first executing entity has acquired the right to occupy the information resource, the first executing entity The second execution entity who has attempted to acquire the access exclusive right to the information resource in a state where the user has acquired the exclusive access right to the information resource by the predetermined timing An access occupancy acquisition determination step for determining whether or not one access occupancy is acquired; and if the second execution entity has not acquired an access occupancy to the information resource by the predetermined timing. If determined, an execution entity selection processing step of selecting a plurality of execution entities including the first execution entity and the second execution entity, and access acquired by the selected execution entities Each of the plurality of execution entities tries to acquire an access occupancy right of at least one of the other access occupancy rights excluding the access occupancy right acquired by itself. An acquisition waiting state determination processing step for determining whether each of the access occupying rights that are in the waiting state for acquisition is waiting for acquisition by at least one of the plurality of execution subjects. And-up, when it is determined that the an acquisition wait state, and executes the an execution stop determination processing step of determining that stopped the processing is in the middle of execution.

  Another aspect of the present invention is an information processing apparatus, wherein the exclusive control program is installed.

  Still another aspect of the present invention provides an execution entity that has attempted to acquire an access occupancy right that is a right for exclusive access to information resources that can be accessed in common by a plurality of execution entities that execute information processing. The access exclusive right is acquired only for one execution entity, and when the access to the information resource from the one execution entity is completed, the access exclusive right is released to the one execution entity. , An exclusive control method for controlling so that only the one execution entity has exclusive access to the information resource, and after the first execution entity has acquired the right to occupy the information resource, In a state where the execution subject has acquired the access exclusive right to the information resource, the second execution entity who has attempted to acquire the access exclusive right to the information resource has received the first Determining whether or not the second occupancy right has been acquired, and if it is determined that the second execution entity has not acquired the right to occupy the information resource by the predetermined timing, A plurality of execution entities including the execution entity and the second execution entity are selected, and the access occupation right acquired by the plurality of execution entities selected is excluded from the access occupation right acquired by the plurality of execution entities. Each of the plurality of execution entities tries to acquire at least one of the other access occupancy rights, and each of the access occupancy rights acquired by the plurality of execution entities is at least one of the plurality of execution entities. Determining whether or not it is in an acquisition waiting state waiting for acquisition, and determining that the information processing is stopped during execution when it is determined that the acquisition waiting state is determined. And butterflies.

  According to the present invention, deadlock can be detected efficiently.

It is a block diagram which shows typically the hardware constitutions of the information processing apparatus which concerns on embodiment of this invention. It is a block diagram which shows typically the function structure of the information processing apparatus which concerns on embodiment of this invention. It is a figure for demonstrating the data structure of the lock | rock which concerns on embodiment of this invention. It is a figure for demonstrating the data structure of the execution main body which concerns on embodiment of this invention. It is a flowchart for demonstrating the process at the time of the operating system which concerns on embodiment of this invention performs a lock acquisition process. It is a flowchart for demonstrating the process at the time of the operating system which concerns on embodiment of this invention performs a lock acquisition process. It is a flowchart for demonstrating the process at the time of the operating system which concerns on embodiment of this invention performing a function return address registration process. It is a flowchart for demonstrating the process at the time of the operating system which concerns on embodiment of this invention performing a lock release process. It is a flowchart for demonstrating the process at the time of the operating system which concerns on embodiment of this invention performing a deadlock possibility determination process. It is a flowchart for demonstrating the process at the time of the operating system which concerns on embodiment of this invention performing a deadlock determination process. It is a figure which shows an example of the directed graph which concerns on this embodiment. It is a figure which shows an example of the combination list | wrist which concerns on this embodiment. It is a figure which shows an example of the directed graph which concerns on this embodiment. It is a flowchart for demonstrating the process at the time of the operating system which concerns on embodiment of this invention performing a debug information output process. It is a figure which shows an example of the combination list | wrist which concerns on this embodiment. It is a figure which shows an example of the directed graph which concerns on this embodiment. It is a figure which shows an example of the combination list | wrist which concerns on this embodiment. It is a figure which shows an example of the directed graph which concerns on this embodiment.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the present embodiment, an operating system that is installed and used in an information processing apparatus such as a PC (Personal Computer), a server, or an image forming apparatus will be described as an example of the exclusive control program.

  The operating system according to the present embodiment has a right to exclusively access information resources that can be accessed in common by a plurality of execution subjects executing information processing, such as processes, threads, and tasks. When the execution occupancy right is acquired only for one execution entity among the execution entities that have attempted to acquire an access occupancy right, and the access to the information resource from the one execution entity is completed, the one execution By causing the main body to release the access right, only the one execution main body is controlled to exclusively access the information resource. Here, the information resource is an element such as data used when the execution subject executes processing, or a special memory area commonly used when the execution subject executes processing.

  Specifically, in the operating system according to the present embodiment, an access occupation right called a lock is linked in advance to an information resource that should be exclusively accessed from the execution subject. In such an operating system, when each executing entity accesses the information resource, each executing entity tries to acquire the lock, and only the executing entity that can acquire the lock has the information. The resource can be accessed.

  At this time, another execution entity that could not acquire the lock waits until the execution entity that has successfully acquired the lock and has accessed the information resource completes access to the information resource and releases the lock. . Thereafter, the executing entity that has completed access to the information resource releases the lock, so that another executing entity waiting to acquire the lock can acquire the lock.

  With such a lock function, in the operating system according to the present embodiment, only a specific execution entity accesses the information resource exclusively, so that a plurality of execution entities can simultaneously access the same information resource. It is possible to avoid this, and it is possible to prevent inconsistencies caused by a plurality of execution subjects rewriting the same data at the same time.

  In the operating system configured as described above, one of the gist according to the present embodiment is a lock that has been acquired by one execution entity and is waiting to be acquired by another execution entity, Executes deadlock determination processing to determine whether or not a deadlock has occurred, only for locks that have not been acquired by another execution entity even after a predetermined time has elapsed since it was acquired by one execution entity There is to do. Thereby, according to the operating system which concerns on this embodiment, it becomes possible to detect a deadlock efficiently.

  First, hardware constituting the information processing apparatus 1 in which the operating system 100 according to the present embodiment is installed will be described with reference to FIG. FIG. 1 is a block diagram schematically illustrating a hardware configuration of the information processing apparatus 1 according to the present embodiment.

  As shown in FIG. 1, the information processing apparatus 1 according to the present embodiment includes a CPU (Central Processing Unit) 10, a RAM (Random Access Memory) 20, a ROM (Read Only Memory) 30, an HDD (Hard Disk Drive) 40, and An I / F 50 is connected via a bus 80. Further, an LCD (Liquid Crystal Display) 60 and an operation unit 70 are connected to the I / F 50.

  The CPU 10 is a calculation unit and controls the operation of the information processing apparatus 1 as a whole. The RAM 20 is a volatile storage medium capable of reading and writing information at high speed, and is used as a work area when the CPU 10 processes information. The ROM 30 is a read-only nonvolatile storage medium and stores a program such as firmware. The HDD 40 is a non-volatile storage medium that can read and write information, and stores an OS (Operating System), various control programs, application programs, and the like.

  The I / F 50 connects and controls the bus 80 and various hardware and networks. The LCD 60 is a visual user interface for the user to check the state of the information processing apparatus 1. The operation unit 70 is a user interface for a user to input information to the information processing apparatus 1 such as a keyboard, a mouse, various hard buttons, and a touch panel.

  In such a hardware configuration, a program stored in a storage medium such as the ROM 30, the HDD 40, or an optical disk (not shown) is read into the RAM 20, and the software control unit is configured by the CPU 10 performing calculations according to those programs. . A functional block that realizes the functions of the information processing apparatus 1 according to the present embodiment is configured by a combination of the software control unit configured as described above and hardware.

  Next, the functional configuration of the information processing apparatus 1 according to the present embodiment will be described with reference to FIG. FIG. 2 is a block diagram schematically showing a functional configuration of the information processing apparatus 1 according to the present embodiment. As shown in FIG. 2, an operating system 100 is installed in the information processing apparatus 1 according to the present embodiment. As illustrated in FIG. 2, the information processing apparatus 1 according to the present embodiment includes a timer 200, a stack 300, an execution subject 400, an information resource 500, and a lock 600.

  The operating system 100 is installed in the information processing apparatus 1 and is subjected to arithmetic processing by a processor such as a CPU (Central Processing Unit), thereby obtaining a lock acquisition processing unit 101, a lock release processing unit 102, a deadlock possibility determination processing unit 103, The deadlock determination processing unit 104, the debug information output processing unit 105, the execution subject management unit 106, the information resource management unit 107, and the lock management unit 108 are configured.

  The lock acquisition processing unit 101 performs a lock acquisition process that is a process when an execution subject acquires a lock associated with an information resource. The lock release processing unit 102 performs a lock release process that is a process for releasing a lock acquired by the execution subject. The deadlock possibility determination processing unit 103 is a process for determining whether there is a possibility that the lock may cause a deadlock for a lock that satisfies a predetermined condition. Perform sex determination processing. Here, a lock that satisfies a predetermined condition is a lock that is acquired by a certain execution subject and has another execution subject that is waiting to be acquired.

  The deadlock determination processing unit 104 determines whether or not a deadlock has actually been caused for a lock that has been determined to possibly cause a deadlock in the deadlock possibility determination processing. A deadlock determination process, which is a process, is performed. When it is determined that the deadlock is actually caused in the deadlock determination process, the debug information output processing unit 105 displays debug information such as a process leading to the occurrence of the deadlock in the display unit such as the LCD 60 or the HDD 40. Debug information output processing that is processing when outputting to a non-volatile storage medium such as is performed.

  The execution subject management unit 106, the information resource management unit 107, and the lock management unit 108 manage the execution subject 400, the information resource 500, and the lock 600, respectively.

  The timer 200 counts the current time. The stack 300 holds a stack frame of functions called in the past. The stack 300 is realized by the register of the CPU 10 shown in FIG. The execution subject 400 is a subject that executes information processing by a processor performing operations such as processes, threads, and tasks. The information resource 500 is an element such as data used when the execution subject executes a process or a special memory area commonly used when the execution subject executes a process. The lock 600 is an access exclusive right for allowing an execution subject to access an information resource exclusively, and is associated with each information resource on a one-to-one basis.

  Next, the data structure of the lock according to the present embodiment will be described with reference to FIG. FIG. 3 is a diagram for explaining the data structure of the lock according to the present embodiment. As shown in FIG. 3, the lock according to the present embodiment includes “lock ID”, “storage destination address”, “acquirer”, “acquisition waiting list”, “acquisition status”, “acquisition time”, “attribute”. , “Function return address”. In FIG. 3, only information related to the present invention is shown, and other information is omitted.

  “Lock ID” is an identifier for identifying a lock. The “storage destination address” is a storage destination address of the lock. “Acquirer” is the storage destination address of the execution subject that has acquired the lock. The “acquisition waiting list” is a list of storage destination addresses of execution subjects waiting to acquire the lock as a result of attempting to acquire the lock. In the present embodiment, the “acquisition waiting list” is registered in the order in which attempts to acquire locks are made, and becomes the acquirer in the order of registration.

  The “acquisition status” is a variable indicating whether or not a lock is acquired by the execution subject. When this variable is 0, it indicates that no acquisition has been acquired from any execution subject. Indicates that there is no other execution entity that has been acquired by a certain execution entity but is waiting to be acquired. If the number is 2 or more, another execution entity that has been acquired by a certain execution entity and is waiting for acquisition. It represents that there is. “Acquisition time” represents a time when lock acquisition is confirmed in the lock acquisition processing.

  “Attribute” is a variable representing the attribute of the lock, and when this variable is 000, it represents a free lock that has not been acquired from any execution subject and has no execution subject waiting to be acquired; If it is 001, it indicates that the lock is acquired by a certain execution subject but no other execution subject is waiting for acquisition. If it is 010, it is acquired by a certain execution subject and waiting for acquisition. It represents that the other execution subject is a lock, and in the case of 011 it represents a lock that has been determined to cause a deadlock as a result of the deadlock possibility determination process, If it is 100, it indicates that it is determined that there is no possibility of causing a deadlock as a result of the deadlock possibility determination process, and if it is 101, it indicates a deadlock. As a result of the determination process, the lock is determined to have caused the deadlock. When the lock is 110, the lock has been determined not to cause the deadlock as a result of the deadlock determination process. In the case of 111, it indicates that the debug information is output as a result of the debug information output process.

  The “function return address” is a return address of a function that goes back by a predetermined step from the time when lock acquisition is confirmed.

  Next, the data structure of the execution subject according to the present embodiment will be described with reference to FIG. FIG. 4 is a diagram for explaining the data structure of the execution subject according to the present embodiment. As shown in FIG. 4, the execution subject according to the present embodiment includes an “execution subject ID”, a “storage destination address”, and an “acquired list”. In FIG. 4, only information related to the present invention is shown, and other information is omitted. The “execution subject ID” is an identifier for identifying the execution subject. The “storage destination address” is a storage destination address of the execution subject. The “acquired list” is a list of storage addresses of acquired locks.

  In the operating system 100 configured as described above, one of the gist according to the present embodiment is a lock that is acquired by one execution entity and is waiting to be acquired by another execution entity. Deadlock determination processing for determining whether or not a deadlock has been caused only for locks that have not been acquired by the other execution entity even after a predetermined time has elapsed since the acquisition by the one execution entity There is to do. Thereby, the operating system 100 according to the present embodiment can efficiently detect a deadlock.

  Next, processing when the operating system 100 according to the present embodiment executes lock acquisition processing will be described with reference to FIGS. 5 and 6 are flowcharts for explaining processing when the operating system 100 according to the present embodiment executes lock acquisition processing. 5 and 6 show an example in which a specific execution subject α acquires a lock a of an information resource A.

  As shown in FIG. 5, when the operating system 100 according to the present embodiment executes the lock acquisition process, first, when the execution subject α tries to acquire the lock a, the lock acquisition processing unit 101 By confirming “acquirer” or “acquisition status”, it is determined whether or not the lock a has already been acquired by another execution subject (S501). The lock acquisition processing unit 101 performs the lock in the determination processing of S501. If it is determined that “a” has not been acquired by another execution subject (S501 / YES), 1 is added to the “acquisition status” variable of lock a (S502).

  When 1 is added to the “acquisition status” variable, the lock acquisition processing unit 101 registers the “storage destination address” of the execution subject α in the “acquirer” of the lock a (S503), and locks by the execution subject α The acquisition of a is confirmed (S504), and the current time at that time is acquired from the timer 200 as the acquisition time of lock a by the execution subject α and registered in the “acquisition time” of lock a (S505). The determination of acquisition of the lock a by the execution subject α may be at another timing, for example, the timing at which the lock acquisition process executed for the execution subject α to acquire the lock a is completed.

  When the current acquisition time is registered in “acquisition time”, the lock acquisition processing unit 101 acquires the return address of the function from the stack 300 and registers it in the “function return address” of the lock a (S506), and at the same time “stores” the lock a. The “execution subject” waiting for acquisition of lock a is registered by registering “destination address” in the “acquired list” of execution subject α (S507) and confirming “acquisition waiting list” or “acquisition status” of lock a. It is determined whether or not there is (S508). That is, in this embodiment, the process of S506 corresponds to an execution process information acquisition process step. The function return address registration process in S506 will be described in detail later with reference to FIG.

  If the lock acquisition processing unit 101 determines in S508 that there is an execution subject waiting for acquisition of lock a (S508 / YES), whether or not the “attribute” of lock a is “010”. Is determined (S509). When the lock acquisition processing unit 101 determines that the “attribute” of the lock a is not 010 in the determination process of S509 (S509 / NO), the lock acquisition processing unit 101 updates the “attribute” of the lock a to 010 (S510). When the lock acquisition process is terminated and it is determined that the value is 010 (S509 / YES), the lock acquisition process is terminated as it is.

  If the lock acquisition processing unit 101 determines that there is no execution subject waiting for acquisition of lock a in the determination processing of S508 (S508 / NO), whether or not the “attribute” of lock a is 001. Is determined (S511). When the lock acquisition processing unit 101 determines that the “attribute” of the lock a is not 001 in the determination process of S511 (S511 / NO), the lock acquisition processing unit 101 updates the “attribute” of the lock a to 001 (S512). When the lock acquisition process is terminated and it is determined that the value is 001 (YES in S511), the lock acquisition process is terminated as it is.

  On the other hand, when the lock acquisition processing unit 101 determines in the determination process of S501 that the lock a has already been acquired by another execution subject (S501 / NO), first, as shown in FIG. The “storage address” of α is registered in the “acquisition waiting list” of lock a (S601), and it is determined whether or not the “attribute” of lock a is 010.

  If the lock acquisition processing unit 101 determines that the “attribute” of the lock a is not 010 (S602 / NO), the lock acquisition processing unit 101 updates the “attribute” of the lock a to 010 (S603), and then the lock release processing unit 102 (S604), if it is determined to be 010 (S602 / YES), the lock release processing unit 102 waits for the lock release process of the lock a to end (S604 / YES). S604). Note that the lock release processing in S604 will be described in detail later with reference to FIG.

  As a result of the lock release processing, the lock acquisition processing unit 101 notifies the execution subject waiting for acquisition of the lock a from the lock release processing unit 102 that notifies the lock release processing unit 102 that the order of acquisition of the lock a has come. Then, it is determined whether the acquisition notification is for the execution subject α (S605).

  If the lock acquisition processing unit 101 determines that the acquisition notification of lock a is not for the execution subject α in the determination processing of S605 (S605 / NO), the other execution entity notified of the acquisition notification of lock a A lock acquisition process for acquiring lock a is executed (S606). Note that the lock acquisition process executed in S606 is the same as the processes in S503 to S512.

  The lock acquisition processing unit 101 waits for the lock release processing of the lock a by the lock release processing unit 102 to end again when the execution of the lock acquisition process for the other execution subject to acquire the lock a is completed ( S604) When the acquisition notification of lock a is notified from the lock release processing unit 102 to the execution subject waiting for acquisition of lock a, it is determined whether or not the acquisition notification is for the execution subject α (S604). S605).

  When the lock acquisition processing unit 101 determines in the determination process of S605 that the acquisition notification of the lock a is to the execution subject α (S605 / YES), the “acquisition address” of the execution subject α is “acquired” of the lock a. The process is deleted from the “waiting list” (S607), and the same processing as the processing after S503 is performed again. In this way, the operating system 100 according to the present embodiment ends the lock acquisition process.

  Next, processing when the operating system 100 according to the present embodiment executes the function return address registration processing will be described with reference to FIG. FIG. 7 is a flowchart for explaining processing when the operating system 100 according to the present embodiment executes function return address registration processing. FIG. 7 shows an example in which the return address of a function is registered in the “function return address” of lock b of an information resource B.

  As shown in FIG. 7, when the operating system 100 according to the present embodiment executes the function return address registration process, first, the lock acquisition processing unit 101 sets the stack frame stacked at the top of the stack 300. Access (S701), obtain the return address of the function included in the stack frame (S702), and register it in the “function return address” of lock b (S703).

  Then, the lock acquisition processing unit 101 accesses the stack frame indicated by the return address of the function acquired one step before (S704), acquires the return address of the function included in the stack frame (S705), After registering in the “function return address” of lock b (S706), it is determined whether or not it has been traced back by a predetermined step (S707).

  If the lock acquisition processing unit 101 determines in the determination process of S707 that the predetermined step is not traced back (S707 / NO), the lock acquisition processing unit 101 performs the same process as the process after S704 again and determines that the predetermined step is traced back. If so (S707 / YES), the function return address registration process is terminated.

  Next, processing when the operating system 100 according to the present embodiment executes the lock release processing will be described with reference to FIG. FIG. 8 is a flowchart for explaining processing when the operating system 100 according to the present embodiment executes lock release processing. FIG. 8 shows an example in which a specific execution subject β releases a lock b of a certain information resource B.

  As shown in FIG. 8, when the operating system 100 according to the present embodiment executes the lock release process, first, when the execution subject β tries to release the lock b, the lock release processing unit 102 1 is subtracted from the variable “acquisition status” (S801). When 1 is subtracted from the “acquisition status” variable, the lock release processing unit 102 clears “acquirer”, “acquisition time”, and “debug information” of lock b (S802, S803, S804) and “acquirement” The storage address of lock b is deleted from the “completed list” (S805), and it is determined whether or not “attribute” of lock b is 000 (S806).

  When the lock release processing unit 102 determines that the “attribute” of lock b is not 000 in the determination process of S806 (S806 / NO), the lock release processing unit 102 updates the “attribute” of lock b to 000 (S807). By checking the “acquisition waiting list” or “acquisition status” of lock b, it is determined whether there is an execution subject waiting for acquisition of lock b (S808). (S806 / YES), as it is, by checking the “acquisition waiting list” or “acquisition status” of lock b, it is determined whether there is an execution subject waiting for acquisition of lock b (S808).

  If the lock release processing unit 102 determines that there is an execution subject waiting for acquisition of lock b in the determination processing of S808 (S808 / YES), it notifies that the order of acquisition of lock b has come. The acquisition notification to be performed is notified to the first execution subject in the “acquisition waiting list” of lock b (S809). When it is determined that there is no execution subject waiting for acquisition of lock b after completing the lock release processing. (S808 / NO), the lock release process is terminated as it is.

  Next, processing when the operating system 100 according to the present embodiment performs deadlock possibility determination processing will be described with reference to FIG. FIG. 9 is a flowchart for explaining processing when the operating system 100 according to the present embodiment performs deadlock possibility determination processing.

  As shown in FIG. 9, when the operating system 100 according to the present embodiment performs the deadlock possibility determination process, first, the deadlock possibility determination processing unit 103 locks the lock whose “attribute” is 010. One is selected from 600 (S901). Hereinafter, the lock selected here is referred to as a lock c.

  When one lock is selected, the deadlock possibility determination processing unit 103 acquires the current time from the timer 200 (S902), and calculates the difference between the current time acquired in S902 and the “acquired time” of the lock c. (S903), it is determined whether or not the difference is equal to or longer than a predetermined time (S904). That is, in the present embodiment, the process of S904 corresponds to an access occupation right acquisition determination processing step. Note that the current time acquisition process in S902 may be performed before the process in S901.

  When the deadlock possibility determination processing unit 103 determines that the difference is equal to or longer than the predetermined time in the determination processing of S904 (S904 / YES), the deadlock possibility determination processing unit 103 determines that the lock c may cause a deadlock ( In S905), the “attribute” of the lock c is updated to 011 (S906). On the other hand, if the deadlock possibility determination processing unit 103 determines that the difference is not greater than or equal to the predetermined time in the determination processing of S904 (S904 / NO), the deadlock possibility determination processing unit 103 determines that the lock c may not cause a deadlock. (S907), the “attribute” of lock c is updated to 100 (S908).

  When the “attribute” of the lock c is updated, the deadlock possibility determination processing unit 103 determines whether there is a lock whose “attribute” is 010 (S909). When the deadlock possibility determination processing unit 103 determines that there is a lock whose “attribute” is 010 in the determination processing of S909 (S909 / YES), the deadlock possibility determination processing unit 103 performs the same processing as the processing after S901.

  On the other hand, if the deadlock possibility determination processing unit 103 determines that there is no lock of 010 in the determination processing of S908 (S909 / NO), all the locks whose “attribute” is 100 are selected from the lock 600. Then, those “attributes” are updated to 010 (S910), the deadlock determination processing unit 104 is notified that the deadlock possibility determination process is completed (S911), and the deadlock possibility determination process is terminated. .

  Here, the reason why the deadlock possibility determination processing unit 103 performs the “attribute” update processing in S910 will be described. Although it is determined that there is no possibility of causing a deadlock in the deadlock possibility determination process, the deadlock possibility determination process is executed again for the lock after a certain amount of time has passed. In this case, in the determination process of S904, it may be determined that the difference is equal to or longer than a predetermined time (S904 / YES).

  That is, in the deadlock possibility determination process, even if it is determined that there is no possibility of causing a deadlock, the deadlock possibility determination process is executed again after a certain amount of time has passed. It remains possible to determine that it may be causing the lock. This is because such a lock is not excluded from the deadlock possibility determination process to be executed again.

  Next, processing when the operating system 100 according to the present embodiment performs deadlock determination processing will be described with reference to FIG. FIG. 10 is a flowchart for explaining processing when the operating system 100 according to the present embodiment performs deadlock determination processing.

  As shown in FIG. 10, when the operating system 100 according to the present embodiment performs the deadlock determination process, the deadlock determination processing unit 104 first determines the deadlock possibility determination from the deadlock possibility determination processing unit 103. When notified that the processing is completed (S1001), one lock whose attribute is 011 is selected from the lock 600 (S1002). Hereinafter, the lock selected here is referred to as a lock d.

  The process of S1002 is one of the gist of the present embodiment. That is, the gist of the operating system 100 according to the present embodiment is to perform a deadlock determination process described below for only a lock whose “attribute” is 011. Thereby, according to the operating system 100 which concerns on this embodiment, it becomes possible to detect a deadlock efficiently.

  The deadlock determination processing unit 104 creates a combination list of the lock d selected in S1002 (S1003). That is, in the present embodiment, the processing of S1002 and S1003 corresponds to an execution subject selection processing step. Here, the combination list of the lock d is an execution subject ID (hereinafter referred to as “execution subject δ”) of an execution subject whose storage destination address is registered in the “acquisition waiting list” of the lock d, and the execution subject δ. The lock ID of the lock whose storage destination address is registered in the “acquired list” (hereinafter referred to as “lock e”) and the execution subject whose storage destination address is registered in the “acquisition waiting list” of lock e The execution subject ID (hereinafter referred to as “execution subject ε”), the lock ID of the lock whose storage destination address is registered in the “acquired list” of the execution subject ε (hereinafter referred to as “lock f”), and Is a list registered for each combination in that order.

  Here, a specific configuration of the combination list according to the present embodiment will be described with reference to FIGS. 11 and 12. FIG. 11 is a diagram illustrating an example of a directed graph according to the present embodiment. FIG. 12 is a diagram showing an example of the combination list according to the present embodiment. Here, the directed graph is a graph configured by indicating the lock acquisition status and the acquisition wait status by the execution subject with arrows having directionality, and the arrow from the execution subject to the lock is the source of the arrow. The execution subject indicates that the arrow-destination lock has been acquired, and the arrow from the lock to the execution subject indicates that the arrow-destination execution subject is waiting to acquire the arrow-source lock. When the directed graph starting from the lock d is as shown in FIG. 11, the combination graph of the lock d is as shown in FIG.

  The deadlock determination processing unit 104 selects one combination for which the selected flag is not set from the combination list of lock d created in S1003 (S1004), sets a selected flag for the combination (S1005), and sets the lock d. And whether or not the lock f in the combination selected in S1004 is the same (S1006). That is, in the present embodiment, the process of S1006 corresponds to an acquisition standby state determination process step.

  When the deadlock determination processing unit 104 determines that the lock d and the lock f are the same in the determination processing in S1006 (S1006 / YES), a deadlock occurs in the combination selected in S1004, and the lock d It is determined that (= lock f) is causing a deadlock (S1007), and the “attribute” of lock d (= lock f) is updated to 101 (S1008). That is, in this embodiment, the process of S1007 corresponds to an execution stop determination process step.

  Here, FIG. 13 shows a directed graph when it is determined that a deadlock has occurred in the combination selected in S1004 (S1006 / YES). FIG. 13 is a diagram illustrating an example of a directed graph according to the present embodiment. As shown in FIG. 13, when a deadlock occurs, a loop is formed in the directed graph. This means that the process of determining whether or not a deadlock has occurred (S1006) corresponds to the process of determining whether or not a loop is formed in the directed graph.

  On the other hand, if the deadlock determination processing unit 104 determines that the lock d and the lock f are not the same in the determination process of S1006 (S1007 / NO), a deadlock occurs in the combination selected in S1004. Otherwise, it is determined that lock d has not caused a deadlock (S1009), and it is determined whether all combinations have been selected from the combination list of lock d (S1010).

  When the deadlock determination processing unit 104 determines that not all combinations have been selected from the combination list of lock d in the determination processing of S1010 (S1010 / NO), the deadlock determination processing unit 104 performs the same processing as the processing after S1004. If it is determined that all combinations have been selected from the combination list of lock d (S1010 / NO), the “attribute” of lock d is updated to 110 (S1011).

  When the “attribute” of the lock d is updated, the deadlock determination processing unit 104 determines whether or not the lock 600 has a lock whose “attribute” is 011 (S1012). When the deadlock determination processing unit 104 determines that there is a lock whose “attribute” is 011 in the determination processing of S1012 (S1012 / YES), the deadlock determination processing unit 104 performs the same processing as the processing from S1002 onward. If it is determined that there is no lock whose attribute is 011 (S1012 / NO), the debug information output processing unit 105 is notified that the deadlock detection process is completed (S1013), and the deadlock determination process is terminated.

  As described above, the operating system 100 according to the present embodiment is a lock that has been acquired by one execution entity and is waiting to be acquired by another execution entity in the deadlock determination process. It is one of the gist to determine whether or not a deadlock has been caused only for the lock that has not been acquired by the other execution entity even after a predetermined time has elapsed since it was acquired by the execution entity. Thereby, according to the operating system 100 which concerns on this embodiment, it becomes possible to detect a deadlock efficiently.

  Next, processing when the operating system 100 according to the present embodiment performs debug information output processing will be described with reference to FIG. FIG. 14 is a flowchart for explaining processing when the operating system 100 according to the present embodiment performs debug information output processing.

  As shown in FIG. 14, when the operating system 100 according to the present embodiment performs the debug information output process, the debug information output process unit 105 first completes the deadlock determination process from the deadlock determination process unit 104. When this is notified (S1401), one lock whose "attribute" is 101 is selected from the lock 600 (S1402). Hereinafter, the lock selected here is referred to as a lock k.

  The debug information output processing unit 105 stores the “storage destination address”, “acquirer”, “acquisition time”, and “function return address” (hereinafter collectively referred to as “debug information”) of the lock k selected in S1402. Is output to a display unit such as the LCD 60 or to a non-volatile storage medium such as the HDD 40 (S1403). That is, in the present embodiment, the process of S1403 corresponds to an execution process information output process step.

  A series of processes of S1402 and S1403 is one of other gist in the present embodiment. That is, the operating system 100 according to the present embodiment has one of the other gist that automatically outputs a process that has fallen into a deadlock when a deadlock occurs. As a result, according to the operating system 100 according to the present embodiment, the user can easily analyze the cause of the deadlock and can always retrieve the information at the time of the deadlock. , You can easily debug anytime and anywhere.

  The debug information output processing unit 105 updates the “attribute” of the lock k to 111 (S1404), and determines whether or not the lock 600 has a lock whose “attribute” is 101 (S1405). If the debug information output processing unit 105 determines in the determination process of S1405 that the lock 600 has a lock whose “attribute” is 101 (S1405 / YES), the debug information output processing unit 105 performs the same process as the process after S1403. If it is determined that there is no lock of “attribute” 101 (S1405 / NO), the debug information output process is terminated as it is.

  As described above, one of the gist according to the present embodiment is a lock that has been acquired by one execution subject and is waiting to be acquired by another execution subject in the deadlock determination process. In other words, it is determined whether or not a deadlock is caused only for a lock that has not been acquired by the other execution entity even after a predetermined time has elapsed since it was acquired by the one execution entity. Thereby, according to the operating system 100 which concerns on this embodiment, it becomes possible to detect a deadlock efficiently.

  In this embodiment, the operating system installed and used in the information processing apparatus has been described as an example. However, the present invention is not limited to this, and a program that allows multiple execution entities to access the same multiple information resources. Any program can be applied.

  In this embodiment, as described in FIGS. 10 to 13, there are two execution entities and two locks, such as “execution entity δ → lock e → execution entity ε → lock f”. An example of creating such a combination list and determining whether or not a loop is formed in the directed graph at that time has been described. In addition, as shown in FIG. 15, a combination list composed of three execution subjects and three locks may be created, and it may be configured to determine whether or not a loop is formed in the directed graph at that time. good. FIG. 14 is a diagram showing an example of the combination list according to the present embodiment.

  In the case of such a configuration, as shown in FIG. 15, in the combination list, in addition to the execution subject δ, lock e, execution subject ε, and lock f described in FIG. The execution subject ID of the execution subject whose storage address is registered (hereinafter referred to as “execution subject λ”) and the lock ID of the lock registered in the “acquired list” of the execution subject λ (hereinafter referred to as “lock”). g ”) are registered in that order. In such a configuration, when a deadlock occurs, for example, the lock g and the lock d described in FIG. 10 are the same, and a loop as shown in FIG. 16 is formed in the directed graph. FIG. 16 is a diagram illustrating an example of the directed graph according to the present embodiment.

  In addition, as shown in FIG. 17, a combination list that is combined with more execution subjects and locks is created, and it is configured to determine whether or not a loop is formed in the directed graph at that time. May be. FIG. 17 is a diagram showing an example of the combination list according to the present embodiment.

  In the case of such a configuration, the combination list is as shown in FIG. 17, and when a deadlock occurs in such a combination list, for example, a loop as shown in FIG. 17 is formed in the directed graph. FIG. 18 is a diagram illustrating an example of a directed graph according to the present embodiment.

  Note that when a loop is formed in a directed graph of two or more execution subjects and locks, the combination subject shown in FIG. 17 is taken as an example, execution subject δ, execution subject ε, execution subject. ,..., execution subject μ,..., lock e, lock f, lock g,..., lock m,. The execution subject δ, the execution subject ε, the execution subject λ,..., The execution subject μ,..., And the execution subject ν each attempt to acquire at least one of the locks other than the acquired lock. , Lock e, lock f, lock g,..., Lock m,..., Lock n are execution subject δ, execution subject ε, execution subject λ,. Waiting for acquisition by at least one of the subjects ν Is Ki.

1 Information processing device 10 CPU
20 RAM
30 ROM
40 HDD
50 I / F
60 LCD
DESCRIPTION OF SYMBOLS 70 Operation part 80 Bus 100 Operating system 101 Lock acquisition process part 102 Lock release process part 103 Deadlock possibility determination process part 104 Deadlock determination process part 105 Debug information output process part 106 Execution subject management part 107 Information resource management part 108 Lock management unit 200 Timer 300 Stack 400 Execution entity 500 Information resource 600 Lock

JP-A-01-140250

Claims (6)

Only for one execution entity among the execution entities that have attempted to acquire an access occupancy right that is a right for exclusive access to information resources that can be accessed in common by a plurality of execution entities executing information processing When an access occupancy right is acquired and access to the information resource from the one execution entity is completed, the one execution entity releases the access occupancy right so that only the one execution entity makes the information resource An exclusive control program for controlling to access exclusively
After the first execution entity acquires the access exclusive right to the information resource, the access exclusive right to the information resource is acquired in the state where the first execution entity has acquired the access exclusive right to the information resource. An access occupancy right acquisition determination processing step for determining whether or not the second execution subject who has attempted acquisition acquires the first access occupancy right by a predetermined timing;
A plurality including the first execution entity and the second execution entity when it is determined that the second execution entity has not acquired the right to occupy the information resource by the predetermined timing. An execution subject selection processing step of selecting an execution subject of
Acquisition of at least one of the other access occupancy rights excluding the access occupancy right acquired among the access occupancy rights acquired by the plurality of selected execution entities, An acquisition in which each execution entity tries to determine whether each of the access occupancy rights acquired by the plurality of execution entities is in an acquisition waiting state waiting for acquisition by at least one of the plurality of execution entities A standby state determination processing step;
An execution stop determination processing step for determining that the information processing is stopped in the middle of execution when it is determined that the state is waiting for acquisition;
The exclusive control program characterized by executing. The execution subject selection processing step includes the first execution subject and the second execution subject when it is determined that the second execution subject has not acquired the access exclusive right to the information resource by the predetermined timing. Execute a step of selecting a second execution subject,
In the acquisition waiting state processing step, the information resource that the selected first execution entity attempted to acquire the access exclusive right is the information resource that the selected second execution entity has acquired the access exclusive right. The exclusive control program according to claim 1, wherein a step of determining whether or not the same is executed is executed.   Acquire execution process information to acquire information about the execution process of information processing executed until the execution entity acquires the access exclusive right to the information resource when the execution entity acquires the access exclusive right to the information resource. The exclusive control program according to claim 1 or 2, wherein a processing step is executed.   The execution process information output processing step for outputting information on the acquired execution process of the information processing is executed when it is determined that the information processing is stopped in the middle of execution. The exclusive control program described.   5. An information processing apparatus in which the exclusive control program according to claim 1 is installed. Only for one execution entity among the execution entities that have attempted to acquire an access occupancy right that is a right for exclusive access to information resources that can be accessed in common by a plurality of execution entities executing information processing When an access occupancy right is acquired and access to the information resource from the one execution entity is completed, the one execution entity releases the access occupancy right so that only the one execution entity makes the information resource An exclusive control method for controlling to access exclusively
Acquiring access right to the information resource in a state where the first execution body has acquired the access right to the information resource after the first executing body has acquired the right to access to the information resource. Determining whether the second execution subject who tried to acquire the first access occupancy right by a predetermined timing;
A plurality including the first execution entity and the second execution entity when it is determined that the second execution entity has not acquired the right to occupy the information resource by the predetermined timing. Select the execution subject of
Acquisition of at least one of the other access occupancy rights excluding the access occupancy right acquired among the access occupancy rights acquired by the plurality of selected execution entities, Each execution entity tries and determines whether each of the access occupancy rights acquired by the plurality of execution entities is in an acquisition wait state waiting for acquisition by at least one of the plurality of execution entities,
An exclusive control method comprising: determining that the information processing is stopped during execution when it is determined that the state is waiting for acquisition.