JP2007328628A - MEMORY MANAGEMENT METHOD, MEMORY MANAGEMENT PROGRAM, AND INFORMATION PROCESSING DEVICE - Google Patents

Abstract

A memory area is allocated by a memory management program so that a mismatch between an application program and a memory can be prevented.
A memory management method using a memory management program, wherein an application program can specify an area reservation request for requesting a memory area reservation from an application program to the memory management program, and the application program can specify a memory area to be secured. A memory management method for allocating a memory area in response to an area allocation request and allocating the memory area allocated in response to the area allocation request to the application program.
[Selection] Figure 3

Description

  The present invention relates to a memory management method, a memory management program, and an information processing apparatus.

  A memory management mechanism usually exists in an information processing apparatus such as a PC or an IT device. The memory management mechanism of the information processing apparatus may be realized by hardware or may be realized by software (Patent Document 1, Patent Document 2, Non-Patent Document 1, and Non-Patent Document 2). In recent information processing apparatuses, a memory management program for managing a memory is often installed as a part of the OS. The allocation of the memory area by the memory management program enables a plurality of application programs to efficiently share a common memory.

However, in the memory area allocation by the conventional memory management program, there is a case where a mismatch between the application program and the memory occurs. For example, a memory area of a remote memory such as an external DRAM is allocated to an application program that requires a proximity memory such as an embedded DRAM. In some cases, the memory area of the adjacent memory was allocated.
JP 2000-35915 A JP 2002-55875 A US Pat. No. 6,684,314 US Patent No. 6530007

  An object of the present invention is to prevent a mismatch between an application program and a memory with respect to allocation of a memory area by a memory management program.

  The present invention is a memory management method using a memory management program, which is an area reservation request for requesting a memory area to be reserved from the application program to the memory management program, so that the application program can specify the memory to secure the memory area. The present invention relates to a memory management method for allocating a memory area in response to an area allocation request and allocating a memory area allocated in response to the area allocation request to the application program.

  The present invention relates to a memory management program, which is an area allocation request for requesting the memory management program to allocate a memory area from the application program, and an area allocation request that allows the application program to specify a memory to allocate the memory area , And a memory management program for causing a computer to execute a memory management method for allocating a memory area allocated in response to the area allocation request to the application program.

  The present invention is an information processing apparatus in which a memory management program is installed, and is an area securing request for requesting the memory management program to secure a memory area from the application program. A memory management program for causing a computer to execute a memory management method for allocating a memory area according to an area allocation request that can be specified and allocating the memory area allocated according to the area allocation request to the application program is implemented. Related to the information processing apparatus.

  According to the present invention, a mismatch between an application program and a memory can be prevented with respect to allocation of a memory area by a memory management program.

(First embodiment)
FIG. 1 is a system configuration diagram of the information processing apparatus 101. The information processing apparatus 101 in FIG. 1 includes a CPU 111, a first memory 112, a second memory 113, and an HDD 114. The CPU 111 is a processor for executing various information processing. The first memory 112 is a mixed DRAM mounted on the same chip as the CPU 111. The second memory 113 is an external DRAM mounted on a chip different from the CPU 111. The HDD 114 is a storage for storing various information. The information processing apparatus 101 in FIG. 1 is equipped with a memory management program 121 and a plurality of application programs 122. These programs are stored in the HDD 114 and operate on the CPU 111.

  FIG. 2 is a data structure diagram for explaining the memory management of the first embodiment.

  The memory management program 121 manages the management information of each memory in the memory management information table 201. In the memory management information table 201, management information 211 in the first memory 112 and management information 221 in the second memory 113 are managed. The management information of each memory includes ID information for identifying the memory, a pointer to the unused area at the beginning of the memory (an unused area with the smallest address) (head area pointer), and the like. The management information 211 in the first memory 112 includes ID information 212 in the first memory 112, a head area pointer 213 in the first memory 112, and the like. The management information 221 in the second memory 113 includes ID information 222 in the second memory 113, a head area pointer 223 in the second memory 113, and the like.

  In the memory in use, there are a used area (memory area in use) 301 and an unused area (memory area not in use) 302. The memory management program 121 stores, in each unused area 302 of each memory, link information (increase direction link information) 311 to an unused area adjacent in the address increasing direction, and the size 321 of the unused area. . Each unused area 302 includes a storage area for increasing direction link information 311, a storage area of size 321, and a remaining area 331. FIG. 2 shows the used area 301 and the unused area 302 of the first memory 112. The downward direction in the figure is the address increasing direction, and the upward direction in the figure is the decreasing direction of the address. It has become.

  FIG. 3 is a flowchart for explaining memory management of the first embodiment.

  When the application program 122 requires memory, the application program 122 transmits an area reservation request for requesting a memory area to the memory management program 121 (step S101). In the area securing request, the size of the memory area to be secured and the memory to secure the memory area can be designated. In other words, the application program 122 that transmits the area reservation request can specify the size of the memory area to be reserved from which memory.

  When receiving the area reservation request, the memory management program 121 searches the memory management information table 201 for the memory designated by the area reservation request (step S111). In this search, each memory is identified using ID information (212, 222) of each memory. Next, the memory management program 121 searches the searched memory for an unused area that can secure a memory area of the size specified by the area securing request (step S112). The search is started from the unused area at the beginning of the memory using the beginning area pointer (213, 223) of the memory, and the increasing direction link information (311) of each unused area of the memory is used. And proceed in the direction of increasing addresses.

  When the memory management program 121 determines that a memory area for a specified size can be secured from a certain unused area 302 (step S113), the memory management program 121 secures a memory area for the specified size starting from the leading address of the unused area 302. (Step S121), the memory area is allocated to the application program 122 (Step S122). At this time, if the size of the unused area 302 is larger than the specified size, the unused area 302 remains smaller by the specified size, so that the value of the size 321 of the unused area 302 is the specified size. It is changed to a value smaller by the minute. On the other hand, when the size of the unused area 302 is equal to the specified size, the unused area 302 disappears, so that the increase direction link information 311 of the unused area 302 immediately before the unused area 302 is The unused area 302 is changed to the unused area 302 immediately after the unused area 302. Next, the memory management program 121 notifies the application program 122 of the start address of the allocated memory area (step S123).

  On the other hand, if the memory management program 121 determines that a memory area of the specified size cannot be secured from any unused area 302 (step S114), it notifies the application program 122 of an error (step S124).

  As described above, in the first embodiment, the memory for securing the memory area can be designated by the area securing request for securing the memory area. That is, the application program 122 that transmits the area reservation request can specify which memory the memory area is reserved from. For example, the application program 122 that requires proximity memory designates the first memory 112 that is an embedded DRAM, or the application program 122 sufficient for remote memory designates the second memory 113 that is an external DRAM. Can do. In this way, in the first embodiment, a mismatch between the application program 122 and the memory can be prevented with respect to the allocation of the memory area by the memory management program 121.

  The memory designation in the first embodiment may be performed for each memory such as “designation of the first memory” and “designation of the second memory”, or “designation of memory of the first group”, “designation of the first group”. It may be performed for each group of memories, such as “specify two groups of memories”. For example, when a plurality of embedded DRAMs and a plurality of external DRAMs are mounted on the information processing apparatus 101, it can be considered that the mixed DRAMs and the external DRAMs are grouped. The grouping of the memory is preferably performed based on the attribute (physical attribute) of the memory (physical memory) such as “mixed or externally mounted”, “DRAM or SRAM”, or “old type or new type”. This is because the attribute of the memory to be used is important for the application program 122. The memory designation for each group may be performed with the group ID such as “designate the memory of the group with ID = 1” or “designate the memory of the group with ID = 2” or “designate the embedded DRAM”. You may decide to carry out by the attribute of a memory like "specify external DRAM". The memory management program 121 determines which memory is selected from a certain group (which embedded DRAM is selected from the embedded DRAM group, which embedded DRAM is selected from the external DRAM group, etc.) based on a certain rule. It may be determined (in order of the ID number of each memory) or may be determined randomly.

  Also, the memory designation in the area securing request of the first embodiment may be “required requirement” (must be specified) or “optional requirement” (may be specified or not specified). When memory specification is an arbitrary requirement, the memory management program 121 that has received an area reservation request without memory specification may reserve a memory area from either the first memory 112 or the second memory 113. (FIG. 4). In this case, for example, the first memory 112 may be a search target first, and then the second memory 113 may be a search target. In this case, the (loop) search process of steps S112, S113, and S114 is executed for the first memory 112 and the second memory 113. Furthermore, a memory area may be secured across the first memory 112 and the second memory 113.

  It supplements about step S124. If a memory area for the specified size is not secured from the designated memory, an error is notified here (step S124). Instead, a memory for the designated size is secured from the non-designated memory. Good. In this case, the (loop) search process of steps S112, S113, and S114 is executed for the designated memory and the non-designated memory. Whether or not to secure memory from the non-designated memory may be specified by the application program 122 in the area securing request.

(Second embodiment)
The second embodiment is a modified embodiment of the first embodiment. Therefore, the second embodiment will be described focusing on the differences from the first embodiment. The system configuration diagram of FIG. 1 is common to the first embodiment and the second embodiment.

  FIG. 5 is a data structure diagram for explaining the memory management of the second embodiment.

  In the memory in use, there are a used area (memory area in use) 301 and an unused area (memory area not in use) 302. The memory management program 121 links each unused area 302 of each memory to link information (increase direction link information) 311 to an unused area adjacent to the address increasing direction and to an unused area adjacent to the address decreasing direction. Link information (decreasing direction link information) 312 and the size 321 of the unused area are stored. Each unused area 302 includes a storage area for increasing direction link information 311, a storage area for decreasing direction link information 312, a storage area of size 321, and a remaining area 331. FIG. 5 shows the used area 301 and the unused area 302 of the first memory 112. The downward direction in the figure is the address increasing direction, and the upward direction in the figure is the decreasing direction of the address. It has become.

  FIG. 6 is a flowchart for explaining memory management of the second embodiment.

  When the application program 122 requires memory, the application program 122 transmits an area reservation request for requesting a memory area to the memory management program 121 (step S101). In the area securing request, it is possible to specify the size of the memory area to be secured, the memory for securing the memory area, and the direction in which the unused area is searched (increase direction or decrease direction). In other words, the application program 122 that transmits the area securing request can specify the memory area of which size from which memory is searched and secured in which direction.

  When receiving the area reservation request, the memory management program 121 searches the memory management information table 201 for the memory designated by the area reservation request (step S111). In this search, each memory is identified using ID information (212, 222) of each memory. Next, the memory management program 121 searches the searched memory for an unused area that can secure a memory area of the size specified by the area securing request (steps S112 and S212). When the search direction specified in the area securing request is the address increasing direction (step S311), the search uses the top area pointer (213, 223) of the memory to start from the unused area at the top of the memory. It is started and proceeds in the address increasing direction using the increasing direction link information (311) of each unused area of the memory (step S112). If the search direction specified in the area securing request is the address decreasing direction (step S311), the search is performed by using the start area pointer (213, 223) of the memory and the increasing direction link information ( 311), and starts from the unused area at the end of the memory, and proceeds in the address decreasing direction using the decreasing direction link information (312) of each unused area of the memory (311). Step S212). In the latter case, the head area pointer is used to find the unused area at the beginning of the memory, and the increasing direction link information traces from the unused area at the beginning of the memory to the unused area at the end of the memory ( It is used for step S312).

  Since steps S113 to S124 have been described, steps S213 to S224 will be described below.

  If the memory management program 121 determines that a memory area for a specified size can be secured from a certain unused area 302 (step S213), the memory management program 121 secures a memory area for the specified size with the end address of the unused area 302 as an end point. (Step S221), the memory area is allocated to the application program 122 (Step S222). At this time, if the size of the unused area 302 is larger than the specified size, the unused area 302 remains smaller by the specified size, so that the value of the size 321 of the unused area 302 is the specified size. It is changed to a value smaller by the minute. On the other hand, when the size of the unused area 302 is equal to the specified size, the unused area 302 disappears, so that the increase direction link information 311 of the unused area 302 immediately before the unused area 302 is The unused area 302 is changed to the unused area 302 immediately after the unused area 302, and the decrease direction link information 312 of the unused area 302 immediately after the unused area 302 is changed to the unused area 302. The area 302 is changed to the unused area 302 immediately before the unused area 302 (the same applies to steps S121 and S122). Next, the memory management program 121 notifies the application program 122 of the start address of the allocated memory area (step S223).

  On the other hand, if the memory management program 121 determines that a memory area of the specified size cannot be secured from any unused area 302 (step S214), it notifies the application program 122 of an error (step S224).

  As described above, the types of link information stored in the unused area 302 are different between the first embodiment and the second embodiment. In the first embodiment, only the increasing direction link information 311 is stored as the link information, whereas in the second embodiment, the increasing direction link information 311 and the decreasing direction link information 312 are stored as the link information. That is, in the first embodiment, the link list of the unused area has a “unidirectional link list structure”, whereas in the second embodiment, the link list of the unused area has a “bidirectional link list structure”. "

  Therefore, in the second embodiment, an unused area for securing a memory area can be searched for in the address increasing direction, or can be searched for in the address decreasing direction. As a result, in the second embodiment, fragmentation of the memory area can be prevented.

  A specific example is shown in FIG. In FIG. 7, the arrangement order of the addresses is such that the first memory 112 is in front and the second memory 113 is in back. The search direction of the unused area in the first memory 112 is the address increasing direction, and if the memory area can be secured from the unused area A, the memory area having the starting address a of the unused area A as the starting point X1 X is secured. The search direction of the unused area in the second memory 113 is the address decreasing direction, and when the memory area can be secured from the unused area B, the memory area having the end address b of the unused area B as the end point Y2. Y is secured. Thereby, securing of the memory area X and the memory area Y is prevented from causing fragmentation.

  Note that the search direction of the unused area may be specified by the application program 122 or may not be specified by the application program 122.

(Third embodiment)
The third embodiment is a modified embodiment of the second embodiment. Therefore, the third embodiment will be described focusing on the differences from the second embodiment. The system configuration diagram of FIG. 1 is common to the second embodiment and the third embodiment.

  FIG. 8 is a data structure diagram for explaining the memory management of the third embodiment.

  The memory management program 121 manages the management information of each memory in the memory management information table 201. In the memory management information table 201, management information 211 in the first memory 112 and management information 221 in the second memory 113 are managed. The management information of each memory includes ID information for identifying the memory, a pointer (head area pointer) to the first unused area (unused area with the smallest address) of the memory, and the end of the memory. It consists of a pointer (end area pointer) to an unused area (an unused area with the largest address). The management information 211 in the first memory 112 includes ID information 212 in the first memory 112, a head area pointer 213 in the first memory 112, a tail area pointer 214 in the first memory 112, and the like. The management information 221 in the second memory 113 includes ID information 222 in the second memory 113, a head area pointer 223 in the second memory 113, a tail area pointer 224 in the second memory 113, and the like.

  FIG. 9 is a flowchart for explaining memory management of the third embodiment.

  When the application program 122 requires memory, the application program 122 transmits an area reservation request for requesting a memory area to the memory management program 121 (step S101). In the area securing request, it is possible to specify the size of the memory area to be secured, the memory for securing the memory area, and the direction in which the unused area is searched (increase direction or decrease direction). In other words, the application program 122 that transmits the area securing request can specify the memory area of which size from which memory is searched and secured in which direction.

  When receiving the area reservation request, the memory management program 121 searches the memory management information table 201 for the memory designated by the area reservation request (step S111). In this search, each memory is identified using ID information (212, 222) of each memory. Next, the memory management program 121 searches the searched memory for an unused area that can secure a memory area of the size specified by the area securing request (steps S112 and S212). When the search direction specified in the area securing request is the address increasing direction (step S311), the search uses the top area pointer (213, 223) of the memory to start from the unused area at the top of the memory. It is started and proceeds in the address increasing direction using the increasing direction link information (311) of each unused area of the memory (step S112). If the search direction specified in the area securing request is the address decreasing direction (step S311), the search is performed from the unused area at the end of the memory by using the end area pointer (214, 224) of the memory. It is started and proceeds in the address decreasing direction using the decreasing direction link information (312) of each unused area of the memory (step S212). Note that step S312 does not exist.

  Steps S113 to S124 are as described in the first embodiment. Steps S213 to S224 are as described in the second embodiment.

  As described above, the types of pointers managed in the memory management information table are different between the second embodiment and the third embodiment. In the second embodiment, only the head area pointer is managed as a pointer, whereas in the third embodiment, a head area pointer and a tail area pointer are managed as pointers.

  Therefore, in the third embodiment, when searching for the unused area at the beginning of the memory, the start area pointer of the memory can be used, and when searching for the unused area at the end of the memory, the memory Can be used. Therefore, in the third embodiment, when searching for an unused area at the end of the memory, it is not necessary to trace from the unused area at the beginning of the memory to the unused area at the end of the memory. Thereby, in the third embodiment, the processing time for reaching the unused area at the end of the memory is shortened. That is, in the third embodiment, the processing time overhead when the unused area search direction is the address decreasing direction is suppressed.

1 is a system configuration diagram of an information processing apparatus. It is a data structure figure for demonstrating the memory management of 1st Example. It is a flowchart figure for demonstrating the memory management of 1st Example. It is a figure for demonstrating the usage method of memory space. It is a data structure figure for demonstrating the memory management of 2nd Example. It is a flowchart figure for demonstrating the memory management of 2nd Example. It is a figure for demonstrating the usage method of memory space. It is a data structure figure for demonstrating the memory management of 3rd Example. It is a flowchart figure for demonstrating the memory management of 3rd Example.

Explanation of symbols

101 Information processing apparatus 111 CPU
112 First memory 113 Second memory 114 HDD
121 memory management program 122 application program 201 memory management information table 211 first memory management information 212 first memory ID information 213 first memory start area pointer 214 first memory end area pointer 221 second memory management information 222 Second memory ID information 223 Second memory start area pointer 224 Second memory end area pointer 301 Used area 302 Unused area 311 Increase direction link information (storage area)
312 Decreasing direction link information (storage area)
321 size (storage area)
331 remaining area

Claims (5)

A memory management method by a memory management program,
A memory area is secured in response to an area securing request that requests the memory management program to secure a memory area from the application program so that the application program can specify the memory that secures the memory area.
A memory management method for allocating a memory area secured in response to the area securing request to the application program. In each unused area of each memory, link information to an unused area adjacent in the address increasing direction and link information to an unused area adjacent in the address decreasing direction are stored,
When searching for an unused area that secures a memory area from an unused area at the beginning of a memory that secures a memory area in the increasing direction of the address, link information to the unused area adjacent to the increasing direction of the address Perform a search using
When searching for an unused area that secures a memory area from the unused area at the end of the memory that secures the memory area in the address decreasing direction, link information to the unused area adjacent in the address decreasing direction The memory management method according to claim 1, wherein the search is executed by using. For each memory, a pointer to the unused area at the beginning of the memory and a pointer to the unused area at the end of the memory are managed,
When searching for an unused area that secures a memory area from the unused area at the beginning of the memory that secures the memory area in the direction of increasing addresses, use a pointer to the unused area at the beginning of that memory. Start the search,
When searching the unused area that secures the memory area from the unused area at the end of the memory that secures the memory area in the address decreasing direction, use a pointer to the unused area at the end of the memory. The memory management method according to claim 2, wherein the search is started. A memory management program,
A memory area is secured in response to an area securing request that requests the memory management program to secure a memory area from the application program so that the application program can specify the memory that secures the memory area.
A memory management program for causing a computer to execute a memory management method for allocating a memory area secured in response to the area securing request to the application program. An information processing apparatus in which a memory management program is implemented,
A memory area is secured in response to an area securing request that requests the memory management program to secure a memory area from the application program so that the application program can specify the memory that secures the memory area.
A memory management program that causes a computer to execute a memory management method for allocating a memory area secured in response to the area securing request to the application program.

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