JP6354609B2 - Information processing apparatus and memory management program - Google Patents

Description

  The present invention relates to an information processing apparatus that arranges data on a memory and a memory management program that operates on the information processing apparatus.

  Conventionally, an efficient memory management method has been demanded. For example, in order to minimize fragmentation of free memory, the database arithmetic processing apparatus disclosed in Patent Document 1 uses data stored in the memory as actual processing data and 2 of parameters necessary for the processing. Classified into types.

  In order to prevent these data from being mixed in the memory, one is arranged from the higher address and the other is arranged from the lower address. In this way, memory fragmentation is reduced by dividing memory areas for data having different characteristics (such as reserved periods) on the memory.

  Further, for example, in the technique disclosed in Patent Document 2, in response to a request for securing a memory smaller than a predetermined size, a memory space used by searching for a free area from a low address to a high address in the memory space is used. In response to a request for securing a large memory of a predetermined size, the memory space is searched from the high address to the low address direction to secure the memory to be used. This suppresses memory fragmentation.

  The techniques disclosed in Patent Document 3 and Patent Document 4 are the same in that the search direction of the empty area is changed according to the required memory size.

Japanese Patent Laid-Open No. 5-324431 JP 2000-047933 A JP 2005-157714 A JP 2005-316839 A

  However, the database processing device disclosed in Patent Document 1 performs limited processing such as sorting on limited data such as actual processing data and parameters necessary for processing in the database, There was no versatility.

  In addition, it takes time and effort to modify the source code of a program that uses memory in order to obtain the effect of reducing the fragmentation of memory in a general information processing device that uses memory. There was a problem. In other words, if the source code to be modified cannot be obtained, the technique of Patent Document 1 could not be made versatile.

In addition, each of the techniques of the above-mentioned patent documents requires processing for determining the search direction of a free area before securing the requested memory, and this processing is an overhead for securing the memory.
In view of the circumstances as described above, an object of the present invention is to provide an information processing apparatus capable of reducing the overhead for appropriately securing a memory by suppressing memory fragmentation and a memory management program that operates in the information processing apparatus. is there.

  In order to achieve the above object, an information processing apparatus according to an aspect of the present invention is capable of switching between a memory used as a work area of a program and a first mode and a second mode. It is necessary to detect a resident program resident in the memory in the mode, store identification information of the resident program in the memory as resident program information, and switch the method for securing the work area in the second mode. And determining whether the request source program that requested the securement of the work area is the resident program by comparing the identification information of the request source program with the resident program information, and Securing the work area of the determined request source program, among the highest address and lowest address of the memory, Starting with either one of them as a starting point, securing the work area of the request source program determined to be other than the resident program is opposite to the starting point of the highest address and the lowest address of the memory And a control unit that starts from the side as a starting point. Therefore, it is possible to reduce the overhead for securing memory appropriately by suppressing memory fragmentation.

  In order to achieve the above object, the information processing apparatus according to an aspect of the present invention further includes a time measuring unit that measures an elapsed time since the information processing apparatus is activated, and the control unit secures the work area. It may be configured to determine whether it is necessary to switch the method based on the elapsed time.

  In order to achieve the above object, in the information processing apparatus according to an aspect of the present invention, the memory includes a resident counter that counts when the request source program is the resident program, and the request source program is other than the resident program. A non-resident counter that counts the case where the request source program is the resident program, the control unit increments the resident counter, clears the non-resident counter, and the request source program If the program is not a resident program, the non-resident counter or the non-resident counter value indicates whether the resident counter needs to be cleared, the non-resident counter is incremented, and the work area allocation method needs to be switched. Judgment based on whether or not But good.

  In order to achieve the above object, a memory management program according to an embodiment of the present invention detects a resident program residing in a memory used as a work area of the program in the first mode and makes the identification information of the resident program resident. Whether it is stored in the memory as program information and in the second mode, and when the method for securing the work area needs to be switched, whether the request source program that requested the work area is the resident program or not Determining the identification information of the request source program and the resident program information, and securing the work area of the request source program that is determined to be the resident program, the highest address of the memory and the lowest It starts with one of the unit addresses as the starting point and is determined to be other than the resident program. Has been to secure the working area of the requesting program, among the highest address and the lowest address of the memory, to execute a procedure to enter the opposite side of the starting point as the starting point to the computer.

  As described above, according to the present invention, it is possible to reduce the overhead for appropriately securing the memory while suppressing the memory fragmentation.

1 is a configuration diagram when a general computer is used as the information processing apparatus 10. FIG. The work areas of the resident program (R1, R2, R3) and the non-resident program (N1, N2) are divided into a high address side and a low address side and are arranged on the RAM 13 FIG. FIG. 3 is a diagram showing a state in which a work area R4 for a resident program is further secured from the state of FIG. It is a flowchart for demonstrating the flow of a process in resident program detection mode. It is a flowchart for demonstrating the outline of the process in normal mode. It is a flowchart for demonstrating the specific example of the process in normal mode. It is a block diagram of information processing apparatus 10 '. It is a flowchart for demonstrating the specific example of the process in normal mode.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

<First Embodiment>
[Overview]
First, an outline of the present embodiment will be described. In this embodiment, a general computer, particularly a PC (Personal Computer) is mainly assumed as the information processing apparatus. However, the present invention is not limited thereto, and may be a control unit incorporated in an image forming apparatus (MFP, Multifunction Peripheral), for example.

  The information processing apparatus according to the present embodiment classifies programs executed on the information processing apparatus into two types, resident programs and non-resident programs, and secures a work area required by the program in the memory for each type. Dividing the location reduces memory fragmentation. In this specification, “reserving a memory” indicates “reserving a work area on a memory”.

  In addition, for each type of program, a process to divide the location to be secured in memory only when necessary so that the process of allocating the work area required by the program in memory is not excessive overhead. Is what you do.

  In the resident program, the work area secured in the memory is used for a long time from the start to the end of the information processing device, whereas in the non-resident program, the program is ended after the program is explicitly started by the user. The work area secured in the memory is used only for a short time until the start.

  That is, there is a difference between a resident program and a non-resident program in which a work area secured on a memory is used for a long time or a short time. In this embodiment, paying attention to this difference, work areas that are released in a short time between work areas that are used for a long time by securing work areas in different areas in the memory between resident programs and non-resident programs. Fragmentation due to the region being sandwiched is reduced.

  Furthermore, the overall overhead for securing the memory is reduced by performing a process for reducing fragmentation only when necessary.

  In the present embodiment, the non-resident program is premised on releasing the work area secured and used on the memory when the program is terminated by a user instruction or the like.

  In the information processing apparatus of this embodiment, first, a resident program is detected in the resident program detection mode (first mode), and a list of resident programs (resident program information) is created. Then, after finishing the resident program detection mode, the information processing apparatus is changed to the normal mode (second mode).

  In normal mode, when it is necessary to divide the work area to be secured in the memory according to the type of program, the information processing device follows the created list and the work area secured by the resident program in the memory and the non-resident program in the memory. By dividing the work area to be secured, the overhead in securing the memory is reduced while the fragmentation of the work area on the memory is reduced.

  The transition from the resident program detection mode to the normal mode may be performed by restarting the information processing apparatus after changing the mode setting of the information processing apparatus according to an explicit instruction from the user.

  The outline of the present embodiment has been described above.

[About resident programs]
Here, the resident program will be described.

  A resident program is a program that is always executed while the information processing apparatus is in operation, and is automatically started even if the user does not explicitly give an instruction to start the program.

  For example, in the case of a PC running Windows (registered trademark) as an OS (Operating System), icons of some resident programs are displayed in a task tray displayed as a part of a GUI (Graphical User Interface) on the display screen. .

  Examples of the resident program include anti-virus software and a messenger for exchanging messages via a network.

  The resident program has been described above.

[How to detect resident programs]
Here, some specific examples of the resident program detection method performed by the information processing apparatus of the present embodiment will be described.

(Method 1)
Judged from the CPU load fluctuation rate. The information processing apparatus is started and the user is not given an instruction to explicitly start the program, and is left as it is. Then, the fluctuation rate of the load of the CPU on which the program is executed is monitored for a certain period, and when the fluctuation rate in the period is kept below a specific value, it is determined that the operating state of the information processing apparatus is stable. Then, it is determined that the program operating at that time is a resident program.

(Method 2)
Judged from CPU load. The information processing apparatus is started and the user is not given an instruction to explicitly start the program, and is left as it is. Then, the load of the CPU on which the program is executed is monitored for a certain period, and when the load during the period is kept below a specific value, it is determined that the operating state of the information processing apparatus is stable. Then, it is determined that the program operating at that time is a resident program.

(Method 3)
This is determined from the OS setting of the information processing apparatus. A list of programs set to be automatically started when the information processing apparatus is started is acquired from the automatic start setting file of the OS.

  Heretofore, some specific examples of the resident program detection method performed by the information processing apparatus of the present embodiment have been described.

[Configuration of Information Processing Apparatus 10]
Next, the configuration of the information processing apparatus 10 will be described. FIG. 1 is a configuration diagram when a general computer is used as the information processing apparatus 10.

  As shown in FIG. 1, an information processing apparatus 10 includes a CPU (Central Processing Unit) 11 (control unit), a ROM (Read Only Memory) 12, a RAM (Random Access Memory) 13 (memory), an operation input unit 14, a network. An interface unit 15, a display unit 16, a storage unit 17, and a time measuring unit 19 are provided, and these blocks are connected via a bus 18. Unless otherwise specified, the term “memory” in the description of this embodiment refers to the RAM 13.

  The ROM 12 fixedly stores a plurality of programs and data such as firmware for executing various processes. The RAM 13 is used as a work area for the CPU 11 and temporarily holds the OS, various applications being executed, and various data being processed.

  The storage unit 17 is, for example, an HDD (Hard Disk Drive), a flash memory, or other nonvolatile memory. In addition to the OS, various applications, and various data, the storage unit 17 stores resident program information 17a described later.

  The network interface unit 15 is connected to a network for exchanging information with other systems, and exchanges information with other systems.

  The CPU 11 expands a program corresponding to an instruction given from the operation input unit 14 among the plurality of programs stored in the ROM 12 or the storage unit 17 in the RAM 13, and the display unit 16 and the storage unit according to the expanded program. 17 is appropriately controlled.

  Further, when the information processing apparatus 10 is in the resident program detection mode, the CPU 11 detects a resident program and stores the detection result as a list of identifiers of the resident program as resident program information in the storage unit 17. Here, the identifier is a program name, a program ID, or the like.

  The operation input unit 14 is, for example, a pointing device such as a mouse, a keyboard, a touch panel, and other operation devices.

  The display unit 16 is, for example, a liquid crystal display, an EL (Electro-Luminescence) display, a plasma display, a CRT (Cathode Ray Tube) display, or the like. The display unit 16 may be built in the information processing apparatus 10 or may be externally connected.

  The timer unit 19 measures an elapsed time after the information processing apparatus 10 is activated. The timer unit 19 may be realized as specific hardware, or realized by using a timer that is usually provided as hardware in a general computer and a program that counts elapsed time from startup. May be.

  The configuration of the information processing apparatus 10 has been described above.

[Method of dividing work area on RAM 13]
Here, a method of dividing the work area secured on the RAM 13 in response to a work area securing request from the program into a resident program and a non-resident program will be briefly described.

  Note that the work area in this embodiment is an area in which instruction codes necessary for executing a program, data necessary for processing, and the like are placed.

  In the present invention, the work area on the RAM 13 may be divided by any method. In the present embodiment, a method of dividing the work area by applying the technique disclosed in Patent Document 1 will be described.

  First, in FIG. 2, the work area is divided into a high-order address side and a low-order address side in the RAM 13 for the resident program (R1, R2, R3) and the non-resident program (N1, N2). Shows the state of placement.

  In FIG. 2, the work areas R1, R2, and R3 of the resident program are arranged from the highest address (one start point) of the memory address of the RAM 13, and from the lowest address (opposite start point) of the memory address. Work areas N1 and N2 for non-resident programs are arranged.

  Then, there are empty areas F1, F2, F3, F4, and F5 that are not secured as work areas, and their positions are determined from empty area chains RC1 and RC2 that indicate the position of the empty area in order from the higher address, and from the lower address. It is represented by empty area chains NC1 and NC2 that represent the positions of the empty areas in order.

  The free area F3 is located between the work area secured from the higher address and the work area secured from the lower address, and is at the position pointed to by both of the free area chains RC2 and NC2.

  Next, FIG. 3 shows a state where a work area R4 for the resident program is secured from the state shown in FIG.

  In FIG. 3, a work area R4 for a resident program is secured on the higher address side of the free area F3 shown in FIG. Then, instead of the empty area chains RC2 and NC2 indicating the empty area F3, the empty area chains RC2 ′ and NC2 ′ are in a state indicating the new empty area F3 ′.

  As described above, when the RAM 13 is used in two types, if the work area is secured from both sides (the highest address and the lowest address) of the address of the RAM 13, the inside of the RAM 13 is efficiently used. I can do it.

  However, the present invention is not limited to this, and the RAM 13 can be divided into three or more types. The case where the work area is used is divided into three or more types according to the length of the period, instead of dividing the period in which the work area is used into two types for the resident program and the non-resident program. It is.

  The method for dividing the work area secured on the RAM 13 in response to the work area securing request from the program into the resident program and the non-resident program has been briefly described above.

[Processing flow]
Here, the flow of processing in the information processing apparatus 10 according to the present embodiment will be described. The explanation is divided into a resident program detection mode and a normal mode.

  First, the flow of processing in the resident program detection mode will be described. FIG. 4 is a flowchart for explaining the flow of processing in the resident program detection mode.

  First, the information processing apparatus 10 is activated in the resident program detection mode (step S10). The activation may be performed by a user instruction or automatically by a timer or the like.

  Next, the CPU 11 detects a resident program after the information processing apparatus 10 is in a stable state. Then, identification information of all detected resident programs is acquired as resident program information 17a (step S11). The method for detecting the resident program is as described above.

  Finally, the CPU 11 stores the resident program information 17a acquired in the previous step in the storage unit 17 (step S12).

  The above is the flow of processing in the resident program detection mode.

  Next, the flow of processing in the normal mode will be described. In the following description, after explaining the outline of the point that is the point of the present invention, a specific example along the outline will be described. FIG. 5 is a flowchart for explaining an outline of processing in the normal mode.

  First, the CPU 11 determines whether it is necessary to change the method for securing the memory by distinguishing the type of program (step S20).

  When it is necessary to change the method for securing the memory (Y in step S20), the CPU 11 determines the memory securing method, that is, the free memory from the lower address depending on the type of program, that is, the resident program or the non-resident program. Whether to secure or switch from the higher address (step S21).

  When there is no need to change the method for securing the memory (N in step S20), the CPU 11 does not determine the type of program or switches the memory securing method according to the determination result, and for example, a specific memory securing method, for example, Memory is uniformly secured using a method of securing free memory from lower addresses (step S22).

  Heretofore, an outline has been given of the parts that are the points of the present invention.

  Next, a specific example along the outline will be described. FIG. 6 is a flowchart for explaining a specific example of processing in the normal mode.

  First, suppose that a program requests memory allocation.

  Next, the CPU 11 refers to the time measuring unit 19 and determines whether or not a specific time has elapsed since the information processing apparatus 10 was activated (step S30). Note that step S30 corresponds to step S20 outlined.

  When the specific time has not yet elapsed (N in Step S30), the CPU 11 next acquires the resident program information 17a from the storage unit 17 (Step S31).

  Next, the CPU 11 determines whether or not the request source program that requested the work area is a resident program by comparing the acquired resident program information 17a with the identification information of the request source program (step S32). ).

  When the request source program is a resident program (Y in step S32), the CPU 11 searches for a free area (free memory) by tracing the free area chains RC1 and RC2 from the highest address in the memory space (step S33).

  When the request source program is not a resident program (N in Step S32), the CPU 11 searches for an empty area (an empty memory) by tracing the empty area chains NC1 and NC2 from the lowest address of the memory space (Step S34).

  Finally, the CPU 11 secures a work area of a necessary size in the free area obtained as a search result (step S35).

  When it is determined in step S30 that the specific time has elapsed (Y in step S30), the CPU 11 traces the empty area chains NC1 and NC2 from the lowest address of the memory space, for example, to thereby check the empty area (empty area). (Memory) is searched (step S36), and a work area of a necessary size is secured in the free area obtained as a search result (step S35).

  The above is the flow of processing in the normal mode.

  Note that the specific time described above is preferably a time when it is estimated that all the resident programs executed when the information processing apparatus 10 is started have been started.

  For example, when the information processing apparatus 10 is a control unit of the image forming apparatus, when the activation of the image forming apparatus is completed and the user can use the image forming apparatus, the image forming apparatus is displayed on the display panel of the image forming apparatus. A message is displayed indicating that it is ready.

  Therefore, based on the fact that a program that displays a message on the display panel indicating that the information processing apparatus 10 has entered a ready state is executed instead of determining completion of activation of the information processing apparatus 10 due to the elapse of a specific time, It may be determined that there is no need to change the method of securing the memory.

  In the above description, it is assumed that when a specific time has elapsed, the start of the resident program is completed, and a program that requests memory after the specific time has elapsed will be a non-resident program.

  Also, in the above explanation, when it is determined that there is no need to change the method of allocating memory, an empty memory is searched from the lowest memory address, but conversely, the search is started from the highest memory address. May be.

  The point here is to suppress memory fragmentation. As long as the same type of program (here non-resident program) can allocate memory continuously, the memory is allocated from the lowest memory address. It does not matter whether it is reserved from the highest memory address.

  The flow of processing in the information processing apparatus 10 according to the present embodiment has been described above.

  The first embodiment has been described above.

<Second Embodiment>
Next, a second embodiment will be described. The difference from the first embodiment is that in the first embodiment, the elapsed time from the start of the information processing apparatus 10 is used to determine whether it is necessary to change the method of securing the memory. In contrast, the second embodiment uses a counter that counts whether the program that requested the memory is a resident program or a non-resident program.

[Configuration of Information Processing Apparatus 10 ′]
First, the configuration of the information processing apparatus 10 ′ will be described. FIG. 7 is a configuration diagram of the information processing apparatus 10 ′. Here, only parts different from the information processing apparatus 10 of the first embodiment will be described.

  The information processing apparatus 10 ′ includes a CPU 11 (control unit), ROM 12, RAM 13 (memory), operation input unit 14, network interface unit 15, display unit 16, and storage unit 17 ′. Connected through.

  In addition to the resident program information 17a, a resident counter 17b and a non-resident counter 17c described later are stored in the storage unit 17 ′.

  The configuration of the information processing apparatus 10 ′ has been described above.

[Processing flow]
Next, the flow of processing in the information processing apparatus 10 ′ will be described. The information sled apparatus 10 ′ also has a resident program detection mode and a normal mode, similar to the information processing apparatus 10, but the outline of the process flow in the resident program detection mode and the process flow in the normal mode are the same. Description will be omitted, and only specific examples in the normal mode will be described.

  FIG. 8 is a flowchart for explaining a specific example of processing in the normal mode.

  Although not shown in the flowchart, it is assumed that the resident counter 17b and the non-resident counter 17c are cleared when the information processing apparatus 10 ′ is activated in the normal mode.

  First, suppose that a program requests memory allocation.

  Next, the CPU 11 determines whether or not the value of the resident counter 17b or the non-resident counter 17c exceeds a specific value (step S40). Note that step S40 corresponds to step S20 outlined.

  If none of the counters exceeds the specific value (N in Step S40), the CPU 11 next acquires the resident program information 17a from the storage unit 17 (Step S41).

  Next, the CPU 11 determines whether or not the request source program that requested the work area is a resident program by comparing the acquired resident program information 17a with the identification information of the request source program (step S42). ).

  When the request source program is a resident program (Y in Step S42), the CPU 11 searches for a free area (free memory) by following the free area chains RC1 and RC2 from the highest address in the memory space (Step S43).

  Next, the CPU 11 increments the resident counter 17b (step S44).

  Next, the CPU 11 clears the non-resident counter 17c (step S45).

  If the request source program is not a resident program in step S42 (N in step S42), the CPU 11 searches the empty area (empty memory) by tracing the empty area chains NC1 and NC2 from the lowest address of the memory space (step S42). S46).

  Next, the CPU 11 increments the non-resident counter 17c (step S47).

Next, the CPU 11 clears the resident counter 17b (step S48).

  Finally, the CPU 11 secures a work area of a necessary size in the free area obtained as a search result (step S49).

  In step S40, if the value of any counter exceeds a specific value (Y in step S40), the CPU 11 traces the empty area chains NC1 and NC2 from the lowest address of the memory space, for example, An area (free memory) is searched (step S50), and a work area of a necessary size is secured in the free area obtained as a search result (step S49).

  The above is the flow of processing in the normal mode.

  Note that the above processing is based on the premise that it is necessary to switch the memory allocation method in order to suppress memory fragmentation in situations where work area requests are made alternately between resident and non-resident programs. Yes.

  Also, for example, if it is determined that the work area request by the non-resident program has been made to some extent because the value of the non-resident counter exceeds a specific value, the activation of the resident program is completed. Assuming that the next work area request is also from a non-resident program. For this reason, the memory allocation method is not switched depending on the type of program, thereby reducing the overhead during memory allocation.

  The second embodiment has been described above.

[Additional notes]
In addition, the present technology is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the present technology.

10, 10 '... Information processing device 11 ... CPU
12… ROM
13 ... RAM
DESCRIPTION OF SYMBOLS 14 ... Operation input part 15 ... Network interface part 16 ... Display part 17, 17 '... Memory | storage part 17a ... Resident program information 17b ... Resident counter 17c ... Non-resident counter 18 ... Bus 19 ... Timing part

Claims (4)

Memory used as a work area for the program,
Switching between the first mode and the second mode is possible,
During the first mode,
Detecting a resident program resident in the memory,
The identification information of the resident program is stored in the memory as resident program information,
When it is necessary to switch the securing method of the work area at the time of the second mode,
It is determined whether the request source program that has requested the securing of the work area is the resident program by comparing the identification information of the request source program with the resident program information,
Securing the work area of the request source program determined to be the resident program starts from one of the highest address and the lowest address of the memory as a starting point,
A control unit that starts securing the work area of the request source program determined to be other than the resident program, starting from a side opposite to the start point of the highest address and the lowest address of the memory; and An information processing apparatus comprising: The information processing apparatus according to claim 1,
It further includes a time measuring unit that measures an elapsed time since the information processing device is activated,
The controller is
An information processing apparatus that determines, based on the elapsed time, whether or not the work area securing method needs to be switched. The information processing apparatus according to claim 1,
The memory stores a resident counter that counts when the request source program is the resident program, and a non-resident counter that counts when the request source program is other than the resident program,
The controller is
If the requesting program is the resident program, increment the resident counter, clear the non-resident counter,
If the requesting program is other than the resident program, clear the resident counter, increment the non-resident counter,
An information processing apparatus that determines whether or not the work area securing method needs to be switched based on whether a value of the resident counter or the non-resident counter exceeds a specific value.


In the first mode,
Detects a resident program that resides in memory used as a work area for the program,
The identification information of the resident program is stored in the memory as resident program information,
In the second mode and when it is necessary to switch the work area securing method,
It is determined whether the request source program that has requested the securing of the work area is the resident program by comparing the identification information of the request source program with the resident program information,
Securing the work area of the request source program determined to be the resident program starts from one of the highest address and the lowest address of the memory as a starting point,
A procedure for starting the securing of the work area of the request source program determined to be other than the resident program, starting from a side opposite to the start point of the highest address and the lowest address of the memory. Memory management program to be executed.

Images