JP2014206871A - Control method, control device, control program and recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To release a storage region in a memory assigned to forcedly ended software.SOLUTION: A control device 100 stores the identifiers of software T1 to T3 in association with memory blocks secured by the software of each of the software T1 to T3 in a storage part 101. The control device 100 specifies memory blocks M1 to M3 still secured by any software by referring to the storage part 101. Then, the control device 100 determines whether or not the software of each of the software T1 to T3 by which the specified memory blocks M1 to M3 are still secured exists among the software under execution. Then, the control device 100 releases the memory blocks still secured by the software determined not to exist among the software under execution.

Description

  The present invention relates to a control method, a control device, a control program, and a recording medium.

  2. Description of the Related Art Conventionally, there is a technique for dynamically allocating a storage area in a memory as a work area for software in order to execute processing defined by software. For example, when the malloc function is called by software, an OS (Operating System) secures a storage area in the memory, and when the free function is called by software, the storage area in the memory secured by the OS is released.

  As a related technique, for example, there is a technique for releasing a plurality of memory areas of the same user at a time. Specifically, the memory user acquires a memory area via the ID registration unit of the memory release control unit, and registers the correspondence between the ID for identifying the memory user and the address of the memory area in the ID management table. . When the memory user determines that the acquired memory is no longer needed, the memory user calls the memory release control unit of the memory release control unit to search for and release a memory area that has not been released from the memory user's ID.

  In addition, there is a technique for collecting resources that become unnecessary due to the termination of an application. For example, when the application execution device provides a resource in response to a request for providing a resource from the application, the identifier for identifying the application that requested the provision of the resource is acquired, and the provided resource and the acquired application identifier are combined. And keep it in the table. When the application is terminated, the application identifier of the terminated application is acquired, the resource corresponding to the acquired identifier is specified from the table, and the specified resource is released. In addition, there is a technique for automatically releasing a memory area by time monitoring without using a release notification from a program that has acquired the memory area.

Japanese Patent Laid-Open No. 11-120073 JP 2002-259146 A JP-A-3-271842

  However, in the above-described conventional technology, when the software is forcibly terminated, the storage area in the memory allocated to the software may not be released. For this reason, for example, the storage area in the memory that has not been released may increase, and the free area in the memory may become insufficient.

  In one aspect, the present invention aims to free storage in memory allocated to software that has been killed.

  According to one aspect of the present invention, from a storage unit that stores a software identifier in association with a use area assigned as a storage area used by software in response to an assignment request from software among storage areas in a memory. The software identifier corresponding to one of the used areas in the memory is acquired, and it is determined whether there is software identified by the acquired identifier in the running software, and the software identified by the identifier When it is determined that there is no data, a control method, a control device, a control program, and a recording medium for releasing any used area are proposed.

  According to one aspect of the present invention, there is an effect that a storage area in a memory allocated to software that has been forcibly terminated can be released.

FIG. 1 is an explanatory diagram of an example of heap memory control of the control device 100 according to the embodiment. FIG. 2 is a block diagram illustrating a hardware configuration example of the control device 100. FIG. 3 is an explanatory diagram showing an example of the data structure of the heap memory M. FIG. 4 is an explanatory diagram showing an example of the data structure of the time information management table 400. FIG. 5 is a block diagram illustrating a functional configuration example of the control device 100. FIG. 6 is an explanatory diagram showing a flow of heap memory control by the control device 100. FIG. 7 is an explanatory diagram showing the update contents of the heap memory M in the initialization process of the control device 100. FIG. 8 is an explanatory diagram showing the update contents of the heap memory M in the securing process of the control device 100. FIG. 9 is an explanatory diagram showing the update contents of the time information management table 400 in the securing process of the control device 100. FIG. 10 is an explanatory diagram showing the update contents of the heap memory M in the release process based on the release request from the software A of the control device 100. FIG. 11 is an explanatory diagram showing the update contents of the time information management table 400 in the release process based on the release request from the software A of the control device 100. FIG. 12 is an explanatory diagram showing the update contents of the heap memory M in the release process based on the determination process of the control device 100. FIG. 13 is an explanatory diagram showing a result of updating the heap memory M in FIG. FIG. 14 is an explanatory diagram showing the update contents of the time information management table 400 in the release process based on the determination process of the control device 100. FIG. 15 is an explanatory diagram showing the update result of the time information management table 400 in FIG. FIG. 16 is a sequence diagram illustrating an example of a control processing procedure of the control device 100. FIG. 17 is a flowchart illustrating an example of the initialization processing procedure of the control device 100. FIG. 18 is a flowchart illustrating an example of a securing process procedure of the control device 100. FIG. 19 is a flowchart illustrating an example of a time management processing procedure of the control device 100. FIG. 20 is a flowchart illustrating an example of the determination processing procedure of the control device 100. FIG. 21 is a flowchart illustrating an example of a release processing procedure of the control device 100.

  Exemplary embodiments of a control method, a control device, a control program, and a recording medium according to the present invention will be described below in detail with reference to the accompanying drawings.

(Example of heap memory control of the control device 100)
FIG. 1 is an explanatory diagram of an example of heap memory control of the control device 100 according to the embodiment. The control device 100 is a computer that releases a memory block in the heap memory M that has been secured by software that has already been executed.

  Here, the software is an instruction code that causes the control apparatus 100 to execute a specified process, and may be a task, a process, or a thread, for example. The software whose execution has ended may be, for example, software that has ended execution of a specified process, software that has been forcibly terminated by a kill command, or software that has been forcibly terminated due to a bug. .

  In other words, the execution-completed software is, for example, software that is not included in the running software. The running software includes, for example, waiting software waiting for time slice assignment if the control device 100 is a multitask system.

  The heap memory M is a storage area used by software, for example. The memory block is, for example, a segmented storage area in the heap memory M and has header information. The header information in the heap memory M is information indicating the attribute of the memory block, for example.

  “Securing” means, for example, allocating a memory block in the heap memory M as a storage area used by software. Release means, for example, that a memory block allocated as a storage area used by software is returned to a state where it is not allocated as a storage area used by specific software. In the following description, a memory block that is not allocated as a storage area used by specific software may be referred to as a “free memory block”.

  In the example of FIG. 1, the control device 100 has a heap memory M. In addition, the control device 100 executes software T1 to T3. Further, in the control device 100, the memory blocks M1 to M3 in the heap memory M are secured by software T1 to T3, respectively. In addition, the control device 100 includes a storage unit 101 that stores the software identifiers of the software T1 to T3 in association with the memory blocks secured by the software T1 to T3.

  Here, an example of the operation in which the control device 100 releases the memory block assured by the software T3 will be described by taking as an example a case where the software T3 being executed is forcibly terminated due to a bug.

  In FIG. 1, (1) the control device 100 refers to the storage unit 101 and identifies the memory blocks M1 to M3 that are secured by any software. (2) The control device 100 determines whether or not each of the software T1 to T3 with the specified memory blocks M1 to M3 remaining is in the software being executed. (3) The control device 100 releases the memory block that has been secured by the software that is determined not to be in the running software. In the following description, a memory block secured by software that is determined not to be in the running software may be referred to as an “abnormal memory block”.

  In the example of FIG. 1, specifically, the control device 100 refers to the storage unit 101 and identifies the software T1 with the memory block M1 secured. Next, the control device 100 determines whether or not the identified software T1 is in the software being executed. Then, the control device 100 determines that the software T1 is in the software being executed, and does not release the memory block M1 that has been secured by the software T1.

  Specifically, the control device 100 refers to the storage unit 101 and identifies the software T3 with the memory block M3 secured. Next, the control device 100 determines whether or not the identified software T3 is in the software being executed. Then, the control device 100 determines that the software T3 is not in the software being executed, and releases the memory block M3 that has been secured by the software T3.

  As a result, the control device 100 can release the memory block secured by the already executed software. Therefore, the control device 100 can prevent a memory block that has been secured by software that has already been executed from increasing and a memory block of the heap memory M from being insufficient (depleted). The shortage of memory blocks means that there is no memory block in the heap memory M having a size to be allocated to software.

  In other words, the control device 100 can prevent a memory leak. As a result, the control device 100 can prevent the memory block in the heap memory M to be allocated to software from being insufficient, and can execute the software normally.

  On the other hand, the control device 100 does not release the memory block that is secured by the running software. Therefore, the control device 100 can prevent a problem occurring in the software being executed by releasing the memory block used by the software being executed. As a result, the control device 100 can execute the software normally.

  In the example of FIG. 1, the control device 100 is a multitask method, but is not limited thereto. For example, the control device 100 may be a single task method.

(Hardware configuration example of control device 100)
FIG. 2 is a block diagram illustrating a hardware configuration example of the control device 100. In FIG. 2, the control device 100 includes a CPU (Central Processing Unit) 201, a ROM (Read Only Memory) 202, a RAM (Random Access Memory) 203, a magnetic disk drive (Hard Disk Drive) 204, and a magnetic disk 205. An optical disk drive 206, an optical disk 207, a display 208, an interface (I / F: Interface) 209, a keyboard 210, a mouse 211, a scanner 212, and a printer 213. Each component is connected by a bus 200.

  Here, the CPU 201 governs overall control of the control device 100. The ROM 202 stores a program such as a boot program. The RAM 203 is used as a work area for the CPU 201. The RAM 203 becomes, for example, a heap memory M. The magnetic disk drive 204 controls reading / writing of data with respect to the magnetic disk 205 according to the control of the CPU 201. The magnetic disk 205 stores data written under the control of the magnetic disk drive 204.

  The optical disk drive 206 controls reading / writing of data with respect to the optical disk 207 according to the control of the CPU 201. The optical disk 207 stores data written under the control of the optical disk drive 206, or causes the computer to read data stored on the optical disk 207.

  The display 208 displays data such as a document, an image, and function information as well as a cursor, an icon, or a tool box. As this display 208, for example, a liquid crystal display, a plasma display, or the like can be adopted.

  The I / F 209 is connected to a network 214 such as a LAN (Local Area Network), a WAN (Wide Area Network), and the Internet through a communication line, and is connected to other devices via the network 214. The I / F 209 controls an internal interface with the network 214 and controls data input / output from an external device. For example, a modem or a LAN adapter may be employed as the I / F 209.

  The keyboard 210 includes keys for inputting characters, numbers, various instructions, and the like, and inputs data. Moreover, a touch panel type input pad or a numeric keypad may be used. The mouse 211 performs cursor movement, range selection, window movement, size change, and the like. A trackball or a joystick may be used as long as they have the same function as a pointing device.

  The scanner 212 optically reads an image and takes in the image data into the control device 100. The scanner 212 may have an OCR (Optical Character Reader) function. The printer 213 prints image data and document data. As the printer 213, for example, a laser printer or an ink jet printer can be adopted. Note that at least one of the optical disk drive 206, the optical disk 207, the display 208, the keyboard 210, the mouse 211, the scanner 212, and the printer 213 may be omitted.

(Example of data structure of heap memory M)
FIG. 3 is an explanatory diagram showing an example of the data structure of the heap memory M.

  As shown in FIG. 3, the heap memory M includes a heap memory header 301 that stores management information of the entire heap memory M, a memory block that is allocated to software, and a memory block header 302 that stores management information of the memory block. Including.

  The heap memory header 301 has fields of size, magic, occupied, myid, next, and prev, and stores management information of the entire heap memory M by setting information in each field.

  In size, the number of bytes in the header is stored. In magic, a magic number is stored. The magic number is an identifier for identifying the format of the heap memory M, for example. Occupied stores information indicating whether or not the heap memory M is in use. In myid, an identifier unique to the heap memory header is stored. In next, a pointer to a memory block header that stores management information of the first memory block among the plurality of memory blocks is stored. The prev stores a pointer to a memory block header that stores management information of the memory block at the end of the plurality of memory blocks.

  The memory block header 302 has fields of “size”, “magic”, “occupied”, “myid”, “next”, and “prev”, and stores management information of the memory block by setting information in each field.

  The number of bytes of the memory block is stored in size. In magic, a magic number is stored. Occupied stores information indicating whether or not the memory block is in use. In myid, an identifier of the software that secures the memory block is stored. The software identifier is, for example, a task ID or process ID, data obtained by combining task ID and time information indicating the time when the task secures a memory block, or a hash value obtained by substituting the combined data into a hash function It is. Next stores a pointer to a memory block header that stores management information of the memory block that is one behind among the plurality of memory blocks. The prev stores a pointer to a memory block header that stores management information of the memory block immediately preceding among the plurality of memory blocks.

(Example of data structure of time information management table 400)
FIG. 4 is an explanatory diagram showing an example of the data structure of the time information management table 400.

  As shown in FIG. 4, the time information management table 400 includes a time field. In time, time information indicating the latest time when the software secures the memory block is stored. The point-in-time information indicating the point in time is, for example, a hash value obtained by substituting the date into a hash function.

  In the example of FIG. 4, the number from the beginning of the record of the time information management table 400 corresponds to the identifier of the software. In other words, the first record from the beginning corresponds to the software identifier “1” and stores time point information indicating the latest time point when the software identified by the software identifier “1” secures the memory block. Therefore, the time information management table 400 has records for the maximum identifier value.

  As described above, the control device 100 stores time information indicating the latest time when the software secures the memory block in association with the software identifier. As a result, when the identifier of software that has already been executed is reused, the control device 100 can cope with the case where a memory block is secured by a plurality of software having the same identifier.

  For example, when the first memory block is secured by the first software identified by a certain identifier, the control device 100 indicates the first time when the first memory block is secured in the first memory block. Are stored in association with each other. Furthermore, the control device 100 stores a certain identifier and first time point information in association with each other.

  Further, it is assumed that the control apparatus 100 allocates an identifier to the second software after the first software is forcibly terminated. Then, when the second memory block is secured by the second software identified by a certain identifier, the control device 100 indicates the second time point when the second memory block is secured in the second memory block. 2 point-in-time information is stored in association with each other. Furthermore, the control device 100 stores a certain identifier in association with the second time point information.

  Here, the control device 100 determines whether or not the first memory block is an abnormal memory block. The control device 100 determines whether or not the first time point information corresponding to the first memory block is the latest time point information among the first time point information and the second time point information corresponding to a certain identifier. judge.

  As a result, the control device 100 determines that the software that secures the first memory block is not the second software to which an identifier is currently allocated but the software to which an identifier has been allocated in the past. To do. Therefore, the control apparatus 100 can determine that the first memory block is an abnormal memory block, assuming that the software that has secured the first memory block has already been executed.

  Here, the control device 100 stores both the first time point information and the second time point information in association with a certain identifier, but the present invention is not limited to this. For example, the control device 100 may store the latest time point information in association with a certain identifier. Thereby, the control apparatus 100 can reduce the size of the storage area used for storing the time point information.

(Functional configuration example of the control device 100)
Next, a functional configuration example of the control device 100 will be described with reference to FIG.

  FIG. 5 is a block diagram illustrating a functional configuration example of the control device 100. The control device 100 includes a storage unit 101, an execution unit 501, an update unit 502, a timing unit 503, an acquisition unit 504, a determination unit 505, and a control unit 506.

  The storage unit 101, the execution unit 501, the update unit 502, the timing unit 503, the acquisition unit 504, the determination unit 505, and the control unit 506 are, for example, the ROM 202, the RAM 203, and the magnetic disk 205 illustrated in FIG. The function is realized by causing the CPU 201 to execute a program stored in a storage device such as the optical disk 207 or by the I / F 209.

  The storage unit 101 stores an identifier of software in association with a use area allocated as a storage area used by software in response to an allocation request from software among storage areas in the memory. The storage unit 101 stores, for example, a software identifier in association with a memory block using a myid field of a memory block header. The storage unit 101 correlates with the use area assigned as the storage area used by the software in response to the assignment request from the software, and indicates the time point when the use area is assigned as the storage area used by the software. Information may be stored.

  In addition, the storage unit 101 stores an identifier of software and time information indicating a time point when a use area is allocated as a storage area used by software in response to an assignment request from the software. For example, using the time information management table 400, the storage unit 101 stores a software identifier and time information indicating the time when the software indicated by the software identifier secures a memory block in association with each other.

  The execution unit 501 executes an OS and software. For example, the execution unit 501 issues an initialization request for the heap memory M by executing the OS. Further, the execution unit 501 issues a memory block reservation request by executing software and executing a malloc function, for example. The execution unit 501 issues a memory block release request by executing software and executing a free function, for example. The execution result is stored in a storage area such as the RAM 203, the magnetic disk 205, and the optical disk 207, for example. Thereby, the execution part 501 can generate triggers, such as a securing process and a release process.

  The update unit 502 updates the heap memory M. For example, the update unit 502 detects an initialization request issued by the execution unit 501 and executes initialization processing of the heap memory M to initialize the heap memory M. In addition, for example, the update unit 502 detects a heap memory M allocation request issued by the execution unit 501, executes a heap memory M allocation process, and stores memory blocks in the heap memory M via the OS. Assign to software. In addition, for example, the update unit 502 detects a release request for the heap memory M issued by the execution unit 501, executes a release process for the heap memory M, and sets a memory block in the heap memory M via the OS. release.

  In addition, when there is an allocation request from software, the update unit 502 stores an identifier of the software in the storage unit 101 in association with the use area requested for allocation. For example, the update unit 502 detects a heap memory M reservation request issued by the execution unit 501 and allocates a memory block to the software executed by the execution unit 501 and issued the reservation request. The update unit 502 stores the software identifier in the myid field of the memory block header. Further, the update unit 502 may store a software identifier and time information indicating the time when the software secures the memory block in the myid field of the memory block header.

  Further, when there is an allocation request from software, the update unit 502 determines whether or not time information corresponding to the identifier of the software is stored in the storage unit 101. And if the update part 502 is memorize | stored, it will memorize | store the time information which shows the time point which allocated the use area | region as a storage area which software uses according to an allocation request instead of the said time point information. For example, the update unit 502 detects a heap memory M securing request issued by the execution unit 501, and the time corresponding to the identifier of the software executed by the executing unit 501 and issued the securing request in the time information management table 400 Update the information to the latest point-in-time information.

  Also, when there is a use area release request assigned as a storage area used by software from the software, the update unit 502 deletes the software identifier corresponding to the use area specified from the release request from the storage unit 101. . The update unit 502 detects, for example, a release request for the heap memory M issued by the execution unit 501, and is executed by the execution unit 501 and issues a release request from the memory block header of the memory block requested for release. Delete the identifier.

  In addition, when there is a use area update request from the determination unit 505 described later, the update unit 502 may delete the software identifier corresponding to the use area specified from the update request from the storage unit 101. For example, the update unit 502 detects an update request for the heap memory M from the determination unit 505, and deletes the software identifier from the memory block header of the memory block requested to be updated. Accordingly, the update unit 502 can update the heap memory header, the heap memory M, the memory block header, and the time information management table to the latest state.

  The timer unit 503 issues a determination request at regular intervals. Thereby, the time measuring part 503 can generate the trigger of a determination process. When the acquisition unit 504 detects a determination request from the timing unit 503, detects a securing request from the execution unit 501, detects a release request from the execution unit 501, or detects an update request from the determination unit 505 The following processing is executed.

  The acquisition unit 504 acquires from the storage unit 101 the software identifier corresponding to one of the used areas in the memory. For example, the acquisition unit 504 acquires a software identifier from the myid field of the memory block header of one of the memory blocks. Further, the acquisition unit 504 may acquire time point information indicating the time point when any of the used areas is allocated from the storage unit 101. For example, the acquisition unit 504 may acquire time information indicating the time when the software secures the memory block together with the software identifier from the myid field of the memory block header of any of the memory blocks. The acquired data is stored in a storage area such as the RAM 203, the magnetic disk 205, and the optical disk 207, for example. Thereby, the acquisition unit 504 can acquire data used for the determination process by the determination unit 505.

  The determination unit 505 determines whether there is software identified by the acquired identifier in the software being executed. For example, the determination unit 505 detects the software state using the acquired software identifier, and when the software is in the idle state, there is no software identified by the acquired identifier in the running software. Is determined.

  If the determination unit 505 determines that there is software identified by the acquired identifier, the storage unit 101 is referred to and the acquired time point information matches the latest time point information corresponding to the acquired identifier. It may be determined whether or not. For example, when the determination unit 505 determines that there is software identified by the acquired identifier, the acquired time point information matches the latest time point information corresponding to the acquired identifier with reference to the time information management table 400. It may be determined whether or not to do so.

  If the determination unit 505 determines that there is no software identified by the identifier, and determines that the acquired time point information does not match the latest time point information, the determination unit 505 issues a release request and an update request for any of the used areas. Issue. The determination result is stored in a storage area such as the RAM 203, the magnetic disk 205, and the optical disk 207, for example. Thereby, the determination unit 505 can determine whether or not the memory block is an abnormal memory block.

  When the control unit 506 determines that there is no software identified by the identifier, the control unit 506 releases any used area. In addition, when it is determined that the acquired time point information does not match the latest time point information, the control unit 506 may release any used area. For example, the control unit 506 detects a release request from the determination unit 505 and releases the memory block requested to be released. Further, the control unit 506 may detect an allocation request from software and allocate a use area to the software. As a result, the control unit 506 can release the memory block secured by the software that has already been executed.

(Specific example of heap memory control by the control device 100)
Next, a specific example of heap memory control by the control device 100 will be described with reference to FIGS.

  FIG. 6 is an explanatory diagram showing a flow of heap memory control by the control device 100. As illustrated in FIG. 6, the control device 100 executes software A, software B, a control program, and an OS.

  In the example of FIG. 6, the OS issues a determination request at regular time intervals. Further, the control program detects a determination request issued from the OS, and executes the processes of the acquisition unit 504, the determination unit 505, and the control unit 506 described above.

  (1) The software A is executed in response to an operation from a user of the control device 100, for example. Here, the software A executes a malloc function and secures a memory block via the OS. At this time, the control program stores the identifier of the software A in the myid field of the memory block header of the secured memory block.

  (2) Software B is executed after software A is interrupted and switched from software A. The control program detects a determination request issued from the OS, interrupts the software B, and is executed after switching from the software B.

  When the control program ends, the software B is switched from the control program and executed. Here, the software B executes a malloc function and secures a memory block via the OS. At this time, the control program stores the identifier of the software B in the myid field of the memory block header of the secured memory block.

  (3) Software A is executed after software B is interrupted and switched from software B. Further, the control program detects a determination request issued from the OS, interrupts the software A, and is executed after switching from the software A.

  When the control program ends, the software A is switched from the control program and executed. Software A executes the free function and releases the memory block via the OS. At this time, the control program deletes the identifier of software A from the myid field of the memory block header of the released memory block. Assume that software A has finished executing.

  Software B is switched from software A and executed because software A has finished executing. Here, it is assumed that software B is forcibly terminated due to a bug. For this reason, the memory block remains secured by the software B.

  (4) The control program is executed by detecting a determination request issued from the OS. The control program acquires the identifier of the software from the myid field of the memory block header of the memory block assured by the software.

  Next, the control program determines whether there is software B identified by the acquired identifier in the software being executed. Here, since there is no software B in the software being executed, the control program determines that the memory block is an abnormal memory block and releases the memory block.

  Thereby, the control program can release the memory block that has been secured by the software that has already been executed. Therefore, the control program can prevent a memory block that has been secured by software that has already been executed from increasing and a memory block of the heap memory M from becoming insufficient. As a result, the control program can prevent the memory block in the heap memory M to be allocated to the software from being insufficient, and can execute the software normally.

  FIG. 7 is an explanatory diagram showing the update contents of the heap memory M in the initialization process of the control device 100. In FIG. 7, the control device 100 initializes the heap memory M. Here, FIG. 7 corresponds to the initial state of FIG.

  As shown in FIG. 7, the control device 100 creates a heap memory header 701, treats the heap memory M as one memory block, and creates a memory block header 702 at the head.

  The control device 100 sets 10000 bytes indicating the size of the memory block in the size field of the created memory block header 702. Here, the size of the memory block is, for example, a result of subtracting the size of the memory block header 702 from 10000 bytes indicating the size of the heap memory M. However, in the following description, for the sake of simplicity, the size of the memory block header 702 is treated as 0 bytes.

  The control device 100 sets 0 indicating that it is unused in the occupied field of the created memory block header 702. The control device 100 sets 0x0 indicating that it is an empty memory block not yet assigned to software in the myid field of the created memory block header 702.

  The control device 100 sets the start address of the heap memory header 701 in the next field of the created memory block header 702. The control device 100 sets the head address of the heap memory header 701 in the prev field of the created memory block header 702.

  The control device 100 stores the top address of the created memory block header 702 in the next of the heap memory header 701. The control device 100 stores the top address of the created memory block header 702 in the prev of the heap memory header 701. Thereby, the control apparatus 100 can initialize the heap memory M.

  FIG. 8 is an explanatory diagram showing the update contents of the heap memory M in the securing process of the control device 100. In FIG. 8, the control device 100 allocates a 100-byte memory block to the software A. Here, the heap memory M shown in FIG. 8 corresponds to the state in which the memory block is allocated to the software A in (1) of FIG.

  As shown in FIG. 8, the control device 100 allocates a 100-byte storage area following the first memory block header 702 to the software A as a memory block, and creates a memory block header 801 at the beginning of the remaining 9900-byte memory block. To do.

  The control device 100 sets 100 bytes indicating the size of the storage area of the memory block allocated to the software A in the size field of the top memory block header 702. The control device 100 sets 1 indicating that it is in use in the occupied field of the top memory block header 702.

  The control device 100 sets 0x00010303 indicating the identifier of the software A and the time when the memory block is allocated to the software A in the myid field of the top memory block header 702.

  The control device 100 sets the top address of the created memory block header 801 in the next field of the top memory block header 702. The control device 100 sets the head address of the heap memory header 701 in the prev field of the head memory block header 702.

  The control device 100 sets 9900 bytes indicating the size of the memory block in the size field of the created memory block header 801. The control device 100 sets 0 indicating that it is unused in the occupied field of the created memory block header 801. The control device 100 sets 0x0 indicating that it is an empty memory block not yet assigned to software in the myid field of the created memory block header 801.

  The control device 100 sets the start address of the heap memory header 701 in the next field of the created memory block header 801. The control device 100 sets the start address of the memory block header 702 in the prev field of the created memory block header 801. The control device 100 updates prev of the heap memory header 701 to the top address of the created memory block header 801. Thereby, the control apparatus 100 can allocate a memory block to the software A. As a result, the control device 100 can execute the software A using the memory block as a work area used for the processing of the software A.

  FIG. 9 is an explanatory diagram showing the update contents of the time information management table 400 in the securing process of the control device 100. In FIG. 9, the control device 100 updates the time information management table 400 when a 100-byte memory block is allocated to the software A. Here, FIG. 9 corresponds to a case where the time information management table 400 is updated when a memory block is allocated to the software A in (1) of FIG.

  Since the identifier of software A is 1, the control device 100 stores time information 0x0303 indicating the time when the memory block is allocated to the software A in the first record of the time information management table 400. Thereby, the control device 100 can store time information indicating the latest time when the memory block is allocated to the software A in association with the software A.

  Also, assume that the control device 100 allocates a 100-byte memory block to the software B and updates the time information management table 400 in the same manner as in FIGS. 8 and 9. Here, as in FIGS. 8 and 9, allocating a 100-byte memory block to software B corresponds to the case of allocating a memory block to software B in (2) of FIG. Thereby, the control apparatus 100 can allocate a memory block to the software B. As a result, the control device 100 can execute the software B using the memory block as a work area used for the processing of the software B. Further, the control device 100 can store time information indicating the latest time when the memory block is allocated to the software B in association with the software B.

  FIG. 10 is an explanatory diagram showing the update contents of the heap memory M in the release process based on the release request from the software A of the control device 100. In FIG. 10, the control device 100 releases the memory block assigned to the software A. Here, FIG. 10 corresponds to the case where the memory block allocated to the software A in (3) of FIG. 6 is released.

  As shown in FIG. 10, the control device 100 releases the memory block assigned to the 100-byte software A following the first memory block header 702.

  Here, the control device 100 refers to the prev field of the memory block header 702 and determines whether or not the memory block header preceding the memory block header 702 is in use. When determining that the preceding memory block header is not in use, the control device 100 couples the memory block header 702 to the preceding memory block header.

  Also, the control device 100 refers to the next field of the memory block header 702 and determines whether or not the memory block header behind the memory block header 702 is in use. When the control device 100 determines that the rear memory block header is not in use, the control device 100 couples the rear memory block header to the memory block header 702. In the example of FIG. 10, the control device 100 does not combine the memory block header 801 because the memory block header 801 behind the memory block header 702 is in use.

  The control device 100 sets 100 bytes in the size field of the top memory block header 702. The control device 100 sets 0 indicating that it is unused in the occupied field of the top memory block header 702. The control device 100 deletes 0x00010303 indicating the identifier of the software A and the time when the memory block is allocated to the software A from the myid field of the top memory block header 702. Thereby, the control apparatus 100 can increase an empty memory block in the heap memory M, and can prevent the heap memory M from running out.

  FIG. 11 is an explanatory diagram showing the update contents of the time information management table 400 in the release process based on the release request from the software A of the control device 100. In FIG. 11, the control device 100 updates the time information management table 400 when releasing the memory block allocated to the software A. Here, FIG. 11 corresponds to the case where the time information management table 400 is updated when the memory block allocated to the software A in (3) of FIG. 6 is released. Since the identifier of the software A is 1, the control apparatus 100 initializes the first record of the time information management table 400 and stores 0x0000. Thereby, the control apparatus 100 can update the time information management table 400.

  FIG. 12 is an explanatory diagram showing the update contents of the heap memory M in the release process based on the determination process of the control device 100. In FIG. 12, the control device 100 releases the memory block allocated to the software B. Here, FIG. 12 corresponds to the case where the memory block allocated to the software B in (4) of FIG. 6 is released.

  As shown in FIG. 12, the control device 100 sequentially acquires the contents of the myid field of the memory block header. For example, the control device 100 acquires the contents of the myid field of the memory block header 801, and acquires the identifier of the software B in the acquired contents and the time information indicating the time when the memory block is allocated to the software B. To do.

  Next, using the acquired identifier of software B, control device 100 determines whether software B is present in the software being executed. Here, since there is no software B in the software being executed, the control device 100 releases the memory block allocated to the software B. The processing for releasing the memory block is the same as the processing shown in FIG.

  In addition, when the software B is included in the software being executed, the control device 100 matches the time point indicated by the acquired time point information with the time point indicated by the time point information of the second record of the time information management table 400. It is determined whether or not to do. Here, if the time points do not match, the control device 100 releases the memory block allocated to the software B. The processing for releasing the memory block is the same as the processing shown in FIG.

  On the other hand, when the time point indicated by the acquired time point information matches the time point indicated by the time point information of the second record of the time information management table 400, the control device 100 does not release the memory block allocated to the software B. .

  FIG. 13 is an explanatory diagram showing a result of updating the heap memory M in FIG. The control device 100 updates the heap memory M as shown in FIG. 13 by executing the processing of FIG. As a result, the control device 100 can release the memory block secured by the already executed software. Therefore, the control device 100 can prevent a memory block that has been secured by software that has already been executed from increasing and a memory block of the heap memory M from becoming insufficient. As a result, the control device 100 can prevent the memory block in the heap memory M to be allocated to software from being insufficient, and can execute the software normally.

  On the other hand, the control device 100 does not release the memory block that is secured by the running software. Therefore, the control device 100 can prevent a problem occurring in the software being executed by releasing the memory block used by the software being executed. As a result, the control device 100 can execute the software normally.

  FIG. 14 is an explanatory diagram showing the update contents of the time information management table 400 in the release process based on the determination process of the control device 100. In FIG. 14, the control device 100 updates the time information management table 400 when releasing the memory block allocated to the software B. Here, FIG. 14 corresponds to the case where the time information management table 400 is updated when the memory block assigned to the software B in (4) of FIG. 6 is released. Since the identifier of software B is 1, the control device 100 initializes the second record of the time information management table 400 and stores 0x0000.

  FIG. 15 is an explanatory diagram showing the update result of the time information management table 400 in FIG. The control device 100 updates the time information management table 400 as shown in FIG. 15 by executing the processing of FIG. Thereby, the control apparatus 100 can update the time information management table 400.

(Example of control processing procedure of control device 100)
Next, an example of a control processing procedure of the control device 100 will be described with reference to FIG.

  FIG. 16 is a sequence diagram illustrating an example of a control processing procedure of the control device 100. In FIG. 16, the execution unit 501 reads the OS, executes the OS, and activates the control device 100 (step S1601). Next, the execution unit 501 transmits an initialization process request to the update unit 502 (step S1602). The update unit 502 detects the initialization process request and executes the initialization process (step S1603). Here, when the updating unit 502 ends the initialization process, the updating unit 502 transmits a response to the execution unit 501.

  The execution unit 501 executes the software (step S1604). The execution unit 501 transmits a reservation request to the update unit 502 and the control unit 506 by executing the malloc function in the software (step S1605). The update unit 502 and the control unit 506 execute a securing process (step S1606). Here, the update unit 502 and the control unit 506 transmit a response to the execution unit 501 when the securing process is completed.

  Here, it is assumed that the software executed by the execution unit 501 is forcibly terminated. The timer unit 503 executes time management processing (step S1607). When the time measuring unit 503 executes the time management process, the update unit 502, the acquisition unit 504, the determination unit 505, and the control unit 506 transmit a determination request.

  When the update unit 502, the acquisition unit 504, the determination unit 505, and the control unit 506 detect the determination request, the update unit 502, the acquisition unit 504, the determination unit 505, and the control unit 506 execute determination processing (step S1608). Here, the update unit 502, the acquisition unit 504, the determination unit 505, and the control unit 506 transmit a response to the time measuring unit 503 when the determination process is completed.

  As a result, the control device 100 can release the memory block secured by the already executed software. Therefore, the control device 100 can prevent a memory block that has been secured by software that has already been executed from increasing and a memory block of the heap memory M from becoming insufficient. As a result, the control device 100 can prevent the memory block in the heap memory M to be allocated to software from being insufficient, and can execute the software normally.

  On the other hand, the control device 100 does not release the memory block that is secured by the running software. Therefore, the control device 100 can prevent a problem occurring in the software being executed by releasing the memory block used by the software being executed. As a result, the control device 100 can execute the software normally.

(Example of initialization processing procedure of control device 100)
Next, an example of an initialization process procedure of the control device 100 will be described with reference to FIG.

  FIG. 17 is a flowchart illustrating an example of the initialization processing procedure of the control device 100. In FIG. 17, the control device 100 acquires the head address of the heap memory M (step S1701). Next, the control device 100 creates a memory block header and sets information in each field of the memory block header based on the acquired head address (step S1702). The control device 100 creates a memory block header and sets information in each field of the memory block header (step S1703). Thereby, the control apparatus 100 can initialize the heap memory M.

(Example of secure processing procedure of control device 100)
Next, an example of the securing process procedure of the control device 100 will be described with reference to FIG.

  FIG. 18 is a flowchart illustrating an example of a securing process procedure of the control device 100. In FIG. 18, the control device 100 determines whether or not all memory blocks have been selected (step S1801). Here, when all the memory blocks are not selected (step S1801: No), the control device 100 refers to the heap memory header and the memory block header and selects a memory block (step S1802).

  Next, the control device 100 determines whether or not the selected memory block is unused and is not less than the size requested to be secured (step S1803). Here, if the control device 100 is not unused or is smaller than the size requested to be secured (step S1803: No), the control device 100 returns to the process of step S1801.

  On the other hand, if it is unused and is not less than the size requested for securing (step S1803: Yes), the control device 100 obtains the identifier of the software that issued the securing request and the time information indicating the secured time. The included data is generated (step S1804). Next, the control device 100 adds an address of the requested size to the start address of the selected memory block, and sets the area after the added address as an empty memory block (step S1805).

  Then, the control device 100 updates the heap memory header and the memory block header (step S1806). Next, the size of the secured memory block is set in the size field of the memory block header of the selected memory block, and 1 indicating in use is set in the occupied field (step S1807).

  Then, the control device 100 sets the generated data in the myid field of the memory block header of the selected memory block (step S1808). Next, the control device 100 sets time information indicating the secured time in the time information management table 400 (step S1809).

  Next, the control device 100 transmits a pointer to the start address of the selected memory block to the execution unit 501 (step S1810). Then, the control device 100 ends the securing process.

  If all the memory blocks are selected in step S1801 (step S1801: Yes), the control device 100 transmits a NULL pointer to the execution unit 501 assuming that the memory block could not be secured (step S1811). Then, the control device 100 ends the securing process. Thereby, the control apparatus 100 can allocate a memory block to software. As a result, the control device 100 can execute the software using the memory block as a work area used for software processing.

(Example of time management processing procedure of the control device 100)
Next, an example of a time management processing procedure of the control device 100 will be described with reference to FIG.

  FIG. 19 is a flowchart illustrating an example of a time management processing procedure of the control device 100. In FIG. 19, the control device 100 determines whether or not a predetermined time has elapsed (step S1901). If the predetermined time has not elapsed (step S1901: No), the control device 100 ends the time management process.

  On the other hand, when the predetermined time has elapsed (step S1901: Yes), the control device 100 issues a determination request (step S1902). Next, the control unit 506 starts counting a predetermined time from the beginning (step S1903). Then, the control unit 506 ends the time management process. Thereby, the control apparatus 100 can issue a determination request at regular time intervals.

(Example of determination processing procedure of control device 100)
Next, an example of the determination processing procedure of the control device 100 will be described with reference to FIG.

  FIG. 20 is a flowchart illustrating an example of the determination processing procedure of the control device 100. In FIG. 20, the control device 100 determines whether or not all memory blocks have been selected (step S2001). Here, when all the memory blocks are not selected (step S2001: No), the control device 100 refers to the heap memory header and the memory block header and selects a memory block (step S2002).

  Next, the control device 100 determines whether or not the selected memory block is in use (step S2003). Here, when the control apparatus 100 is not in use (step S2003: No), the control apparatus 100 returns to the process of step S2001.

  On the other hand, if it is in use (step S2003: Yes), the control device 100 determines the identifier of the software that secured the selected memory block from the myid field of the memory block header of the selected memory block, and the secured time point. The data including the time point information shown is acquired (step S2004). Next, the control device 100 acquires time point information indicating the latest time point when the software identified by the software identifier included in the acquired data secures the memory block from the time information management table 400 (step S2005).

  Then, the control device 100 determines whether or not the time indicated by the time information included in the acquired data matches the latest time indicated by the time information indicating the latest acquired time (step S2006). Here, when it does not correspond (step S2006: No), the control apparatus 100 returns to the process of step S2001.

  On the other hand, when it corresponds (step S2006: Yes), the control apparatus 100 specifies the state of software from the identifier of software (step S2007). Next, the control device 100 determines whether or not the software state is an idle state (step S2008). Here, when it is not an idle state (step S2008: No), the control apparatus 100 returns to the process of step S2001. On the other hand, when it is an idle state (step S2008: Yes), the control apparatus 100 performs a release process (step S2009), and returns to the process of step S2001.

  If all the memory blocks are selected in step S2001 (step S2001: Yes), the control device 100 ends the determination process assuming that there is no memory block to be released. Thereby, the control apparatus 100 can determine whether the memory block allocated to software is an abnormal memory block.

(Example of release processing procedure of control device 100)
Next, an example of a release process procedure of the control device 100 will be described with reference to FIG.

  FIG. 21 is a flowchart illustrating an example of a release processing procedure of the control device 100. In FIG. 21, the control device 100 determines whether or not the memory block preceding the selected memory block is unused (step S2101). Here, when the control apparatus 100 is not unused (step S2101: No), it transfers to the process of step S2103.

  On the other hand, when it is unused (step S2101: Yes), the control device 100 combines the selected memory block with the memory block preceding the selected memory block (step S2102).

  Next, the control device 100 determines whether or not the memory block behind the selected memory block is unused (step S2103). Here, when the control apparatus 100 is not unused (step S2103: No), it transfers to the process of step S2105.

  On the other hand, when unused (step S2103: Yes), the control device 100 couples the memory block behind the selected memory block to the selected memory block (step S2104).

  Next, the control device 100 sets information in the memory block header of the selected memory block or the combined memory block, and sets it as an unused memory block (step S2105). Then, the control device 100 clears the contents of the selected memory block or the combined memory block (step S2106). Next, the control device 100 sets information in the heap memory header (step S2107). Then, the control device 100 ends the release process. Thereby, the control apparatus 100 can release the abnormal memory block.

  As described above, according to the control device 100, if the memory block secured in the software is not included in the software being executed, it can be determined that the memory block is an abnormal memory block. As a result, the control device 100 can release the memory block secured by the already executed software.

  Therefore, the control device 100 can prevent a memory block that has been secured by software that has already been executed from increasing and a memory block of the heap memory M from becoming insufficient. As a result, the control device 100 can prevent the memory block in the heap memory M to be allocated to software from being insufficient, and can execute the software normally. Moreover, the control apparatus 100 can collect the empty memory blocks in the heap memory M, and can improve the efficiency of searching for the memory blocks in use.

  Here, for example, it is conceivable to automatically release the memory block when a predetermined time has elapsed since the start of software execution. However, in this case, if the software is still being executed when the predetermined time has elapsed, the memory block being used by the software may be released and the software may malfunction. On the other hand, the control device 100 does not release the memory block that is secured by the running software. Therefore, the control device 100 can prevent a problem occurring in the software being executed by releasing the memory block used by the software being executed. As a result, the control device 100 can execute the software normally.

  Further, according to the control device 100, the time information indicating the time when the memory block is secured is stored in association with the memory block, and the software identifier is associated with the time information indicating the latest time when the software secures the memory block. It can be memorized. As a result, the control device 100 determines whether or not the time when the memory block is secured coincides with the latest time when the software secures the memory block, and determines whether or not the software identifier is reused. be able to. Therefore, the control device 100 can reduce the amount of data used for the software identifier.

  The control method described in this embodiment can be realized by executing a program prepared in advance on a computer such as a personal computer or a workstation. This control program is recorded on a computer-readable recording medium such as a hard disk, a flexible disk, a CD-ROM, an MO, and a DVD, and is executed by being read from the recording medium by the computer. The control program may be distributed via a network such as the Internet.

  The following additional notes are disclosed with respect to the embodiment described above.

(Supplementary note 1)
One of the storage areas in the memory from the storage unit that stores the identifier of the software in association with the use area allocated as the storage area used by the software in response to an allocation request from the software in the storage area in the memory Get the software identifier corresponding to the used area of
It is determined whether there is software identified by the acquired identifier among the software being executed,
When it is determined that there is no software identified by the identifier, the one of the used areas is released.
A control method characterized by executing processing.

(Appendix 2) The computer
When there is a request for releasing a use area allocated as a storage area used by the software from the software, a process of deleting the identifier of the software corresponding to the use area specified from the release request is executed from the storage unit The control method according to supplementary note 1, wherein:

(Supplementary Note 3) The storage unit is used as an identifier of the software and a storage area used by the software in association with a use area assigned as a storage area used by the software in response to an allocation request from the software. Storing time point information indicating a time point when the area is allocated,
The process to obtain is
From the storage unit, obtain an identifier of software corresponding to any one of the used areas, and time information indicating a time when any of the used areas are allocated,
The determination process is as follows:
When it is determined whether there is software identified by the acquired identifier among the software being executed, and when it is determined that there is software identified by the acquired identifier, the software identifier and the software With reference to the second storage unit that stores the time point information indicating the time point when the use area is assigned as the storage area used by the software in response to the assignment request from the second storage unit, the acquired time point information is It is determined whether or not it matches the latest point-in-time information corresponding to the acquired identifier,
The releasing process is
The control method according to appendix 1 or 2, wherein when the acquired time point information is determined not to match the latest time point information, any one of the used areas is released.

(Appendix 4) The computer
When there is an allocation request from the software, if the time information corresponding to the identifier of the software is stored in the second storage unit, the software responds to the allocation request instead of the time information. The control method according to appendix 3, wherein a process of storing time point information indicating a time point when the use area is allocated as the storage area to be used is executed.

(Supplementary Note 5) A storage unit that stores an identifier of the software in association with a use area assigned as a storage area used by the software in response to an assignment request from software among storage areas in the memory;
An acquisition unit that acquires an identifier of software corresponding to any use area in the memory from the storage unit;
A determination unit that determines whether there is software identified by the identifier acquired by the acquisition unit in the software being executed;
When it is determined by the determination unit that there is no software identified by the identifier, a control unit that releases any of the used areas;
A control device comprising:

(Appendix 6)
One of the storage areas in the memory from the storage unit that stores the identifier of the software in association with the use area allocated as the storage area used by the software in response to an allocation request from the software in the storage area in the memory Get the software identifier corresponding to the used area of
It is determined whether there is software identified by the acquired identifier among the software being executed,
When it is determined that there is no software identified by the identifier, the one of the used areas is released.
A control program characterized by causing a process to be executed.

(Appendix 7)
One of the storage areas in the memory from the storage unit that stores the identifier of the software in association with the use area allocated as the storage area used by the software in response to an allocation request from the software in the storage area in the memory Get the software identifier corresponding to the used area of
It is determined whether there is software identified by the acquired identifier among the software being executed,
When it is determined that there is no software identified by the identifier, the one of the used areas is released.
A computer-readable recording medium having recorded thereon a control program characterized by executing the processing.

DESCRIPTION OF SYMBOLS 100 Control apparatus 501 Execution part 502 Update part 503 Time measuring part 504 Acquisition part 505 Determination part 506 Control part

Claims (6)

Computer
One of the storage areas in the memory from the storage unit that stores the identifier of the software in association with the use area allocated as the storage area used by the software in response to an allocation request from the software in the storage area in the memory Get the software identifier corresponding to the used area of
It is determined whether there is software identified by the acquired identifier among the software being executed,
When it is determined that there is no software identified by the identifier, the one of the used areas is released.
A control method characterized by executing processing. The computer is
When there is a request for releasing a use area allocated as a storage area used by the software from the software, a process of deleting the identifier of the software corresponding to the use area specified from the release request is executed from the storage unit The control method according to claim 1, wherein: In response to an allocation request from the software, the storage unit allocates the software identifier and the use area as the storage area used by the software in association with the use area assigned as the storage area used by the software. Time point information indicating the time point,
The process to obtain is
From the storage unit, obtain an identifier of software corresponding to any one of the used areas, and time information indicating a time when any of the used areas are allocated,
The determination process is as follows:
When it is determined whether there is software identified by the acquired identifier among the software being executed, and when it is determined that there is software identified by the acquired identifier, the software identifier and the software With reference to the second storage unit that stores the time point information indicating the time point when the use area is assigned as the storage area used by the software in response to the assignment request from the second storage unit, the acquired time point information is It is determined whether or not it matches the latest point-in-time information corresponding to the acquired identifier,
The releasing process is
3. The control method according to claim 1, wherein, when it is determined that the acquired time point information does not match the latest time point information, the one of the used areas is released. A storage unit for storing an identifier of the software in association with a use area assigned as a storage area used by the software in response to an assignment request from software among storage areas in the memory;
An acquisition unit that acquires an identifier of software corresponding to any use area in the memory from the storage unit;
A determination unit that determines whether there is software identified by the identifier acquired by the acquisition unit in the software being executed;
When it is determined by the determination unit that there is no software identified by the identifier, a control unit that releases any of the used areas;
A control device comprising: On the computer,
One of the storage areas in the memory from the storage unit that stores the identifier of the software in association with the use area allocated as the storage area used by the software in response to an allocation request from the software in the storage area in the memory Get the software identifier corresponding to the used area of
It is determined whether there is software identified by the acquired identifier among the software being executed,
When it is determined that there is no software identified by the identifier, the one of the used areas is released.
A control program characterized by causing a process to be executed. On the computer,
One of the storage areas in the memory from the storage unit that stores the identifier of the software in association with the use area allocated as the storage area used by the software in response to an allocation request from the software in the storage area in the memory Get the software identifier corresponding to the used area of
It is determined whether there is software identified by the acquired identifier among the software being executed,
When it is determined that there is no software identified by the identifier, the one of the used areas is released.
A computer-readable recording medium having recorded thereon a control program characterized by executing the processing.

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