JP4176682B2 - Memory management method - Google Patents

Description

  The present invention relates to a memory management method in an apparatus using a memory such as an information processing apparatus or an image processing apparatus, and in particular, includes a plurality of fixed-length memory areas having a predetermined data size secured in advance in a variable-length area on the memory. The present invention relates to a memory management system for changing a fixed-length memory block area to an original variable-length area.

Conventionally, various methods have been proposed and implemented as methods for managing memory, and these methods are roughly classified into variable-length memory management methods and fixed-length memory management methods.
In the variable-length memory management system, for example, when an allocation request for data of size α is issued by a CPU or the like, a free area (unused area) that can accommodate the data of size α in order from the start address of the memory, that is, free Whether or not there is a designated memory area is searched (search process), and if it is determined that there is a free area that satisfies the allocation request based on the search result, the free area is the size α and the remaining free areas. (Area division processing), and then data is allocated to the empty area of the size α. In addition, when a request to release the allocated data is issued, the usage status of the memory area before and after the area released after the data in the allocated area of the memory address specified by the CPU or the like is erased is confirmed. If there are adjacent empty areas, a process of merging a plurality of empty areas (area merging process) is performed.
As described above, according to the variable-length memory management method, as long as there is an empty area that can accommodate data, memory allocation of an arbitrary size can be performed according to the requested size. Is unlikely to occur. Therefore, the memory area can be used efficiently. However, on the other hand, pre-processing such as the above-described search process or the above-described area dividing process for the free area performed at the time of allocation, and post-processing such as the above-described area merging process or free area chain process performed at the time of release are accompanied. Therefore, the speed of each process in memory management becomes slow. In particular, the end address portion of the memory takes time for the above-described search process at the time of allocation, and the processing speed tends to extremely decrease.
On the other hand, in the fixed-length memory management method, the memory area is divided into a plurality of memory cells having a predetermined size (synonymous with the fixed-length memory area), and the memory is managed in units of the memory cells. Therefore, there is an advantage that the memory area can be allocated and released at high speed. However, as the size of the memory cell is increased, the number of managed memory cells is reduced and the processing speed is increased. However, since the fraction of the memory cell when data is allocated to the memory cell increases, There is a problem that a useless memory area that cannot be used in the memory cell is generated, and the use efficiency of the memory is deteriorated.

Therefore, as shown in Patent Document 1, a memory is divided into a plurality of fixed-length memory cells having a predetermined data size, taking advantage of the fixed-length memory management method, and responding to allocation / release requests for variable-length areas. On the other hand, a bit map that records the usage status of each memory cell as a bit value of “0” or “1” is provided as management data, and this bit map is managed to allocate and release variable length memory. By doing so, a memory management method has been proposed that reduces the problems of the conventional variable-length memory management method.
JP-A-8-221817

However, since the memory management method proposed in Patent Document 1 corresponds to variable-length data using a plurality of fixed-length memory cells, there are problems described in (1) to (3) below. there were.
(1) Since it is necessary to allocate consecutive memory cells to one variable length data, unused memory cells are distributed in the dynamic memory area when memory cell allocation and release are repeated. As a result, the number of consecutive unused memory cells decreases, and the use efficiency of the memory decreases.
(2) Since a fixed-length memory cell is used, the last memory of a plurality of allocated memory cells when variable-size data is requested to be allocated below the size of the memory cell, as in the past. Since useless fractions are generated in the cells, the memory usage efficiency decreases.
(3) Since it is necessary to store data such as the bitmap other than the actual data in the memory, the storage management area for the actual data in the memory management area is relatively reduced.

Each of the above problems of the memory management system of Patent Document 1 described above can be solved by the following memory management system X. That is, when a predetermined size data allocation / release request is made, a plurality of fixed length memory areas (fixed length memory cells and fixed length memory cells) are stored in the variable length memory area on the variable length memory managed by the variable length memory management method. The fixed-size memory block is allocated, and the data of the predetermined size is allocated to and released from a plurality of fixed-size memory areas in the secured fixed-size memory block. When all of the plurality of fixed-length memory areas are released, the memory management system X for changing the fixed-length memory block to the original variable-length memory area is adopted, so that the memory area can be obtained without causing the above problems. Can be used effectively. The details of the memory management system X will be described in the detailed description of the later invention.
However, when the fixed-size memory block is changed to the original variable-length area using the memory management method X, the following problems may occur. For example, since all the fixed-sized memory areas in the fixed-sized memory block have been released, the process of changing the fixed-sized memory block to the original variable-sized area is performed, and immediately after that, the allocation of the data of the predetermined size is performed. When the request is made, a process of newly reallocating the fixed-length memory block is performed. For this reason, when the allocation and release to the fixed-length memory area are continuously performed, the change process and the securing process are repeatedly performed. If the change process and the secure process are repeatedly performed in this way, the size of the fixed-size memory block is much larger than the size of the memory area that is simply allocated and released, so the change process and the secure process are executed. There is a problem that the burden on the CPU, the memory controller, etc. increases.
Accordingly, the present invention has been made in view of the above circumstances, and the object of the present invention is to temporarily change the area of the fixed-length memory block secured in the variable-length memory area to the original variable-length area. Provides a memory management method with high use efficiency without causing unusable areas that cannot be used in the memory, which eliminates repetitive processing that can generate a large processing load and performs memory allocation and release processing at high speed. There is to do.

To achieve the above object, the present invention changes an area of a fixed-length memory block composed of a plurality of fixed-length memory areas having a predetermined data size previously secured in a variable-length area on a memory to the original variable-length area. In the memory management method, when two or more fixed-length memory blocks are secured in a variable-length area on the memory, at least two fixed lengths of the two or more secured-length memory blocks secured all of the fixed-length condition that a memory area is opened in the memory block, the overall one fixed-length memory block one of the two or more fixed-size memory blocks in which the fixed-length memory area is all open change the region based on the variable-length area, the fixed-length memory block if the fixed-length memory area are all opened the fixed-length memory block is one Is configured as a memory management method, characterized in that no change to the original variable-length area.
Further, in the configuration in which the fixed-length memory area is chain-managed by executing chain reassignment as the fixed-length memory area of the fixed-length block is allocated / released, two or more variable-length areas on the memory are provided. When the fixed-length memory block is secured, all the fixed-length memory areas in any one of the fixed-length memory blocks of the two or more fixed-length memory blocks secured in the variable-length area are released. When there is no fixed-length memory block in which all the fixed-length memory area is released other than the one fixed-length memory block, the fixed-length memory area of the one fixed-length memory block is changed to the original variable length. There is the fixed-size memory block in which the fixed-size memory area is completely released in addition to the single fixed-size memory block. The case it is desirable to change the original variable-length area fixed length memory area of said one fixed-size memory blocks before performing the replacement of the chain.

As described above, according to the present invention, when two or more fixed-length memory blocks including a plurality of fixed-length memory areas having a predetermined data size are secured in advance in the variable-length area on the memory, Two or more fixed areas in which all the fixed length memory areas are released on condition that all the fixed length memory areas in at least two fixed length memory blocks of the above fixed length memory blocks are released. If any one of a fixed length and change the memory block the entire area to the original variable-length area, the fixed-length memory block in which the fixed-length memory area is all open of the long memory block is one because it is configured not to change the fixed-size memory blocks to the original variable-length area, once all the fixed-length memory area in the fixed-length memory block one which is secured Even when released, the single fixed-length memory block when the fixed-length memory area is all open the fixed-length memory block is one is not changed to the original variable-length area, Only when there are two or more fixed-length memory blocks in which all the fixed-length memory areas are released, only one fixed-length memory block is changed to the original variable-length area. Therefore, even if a data allocation request for a fixed-sized memory area is newly made, an unused (empty) fixed-sized memory block already exists and there is no need to reallocate the fixed-sized memory block. Not only is the burden of allocation and release processing in management reduced, but overall high-speed allocation and release processing can be realized.
Further, in the configuration in which the fixed-length memory area is chain-managed by executing chain reassignment as the fixed-length memory area of the fixed-length block is allocated / released, two or more variable-length areas on the memory are provided. When the fixed-length memory block is secured, all the fixed-length memory areas in any one of the fixed-length memory blocks of the two or more fixed-length memory blocks secured in the variable-length area are released. When there is no fixed-length memory block in which all the fixed-length memory area is released other than the one fixed-length memory block, the fixed-length memory area of the one fixed-length memory block is changed to the original variable length. There is the fixed-size memory block in which the fixed-size memory area is completely released in addition to the single fixed-size memory block. In this case, the chain for the one fixed-sized memory block is changed by changing the fixed-sized memory area of the one fixed-sized memory block to the original variable-sized area before executing the chain replacement. The processing burden for re-installing is reduced.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings so that the present invention can be understood. The following embodiment is an example embodying the present invention, and does not limit the technical scope of the present invention.
FIG. 1 is a block diagram showing a hardware configuration for realizing the memory management method X of the present invention. FIG. 2 is a diagram created in the management area 6 of FIG. FIG. 3 is a schematic diagram showing the state of the real data area 7 when data is sequentially allocated to the real data area 7 of FIG. 1, and FIG. 4 is a memory management means 4. FIG. 5 is a schematic diagram for explaining the procedure for creating the area BB1 of the fixed-length memory block, and FIG. 6 is a diagram for explaining the procedure for creating the fixed-length memory block. FIG. 7 is a schematic diagram for explaining the procedure for allocating the fixed-length memory area in the area BB1, and FIG. 7 explains the post-processing after allocating the fixed-size memory area 11 at the memory address 611. FIG. 8 is a schematic diagram for releasing the fixed length memory area 11 of the start address 711 in the fixed length memory block BB3 among the three fixed length memory block areas BB1 to BB3 created in the actual data area 7 of FIG. FIG. 9 is a schematic diagram for explaining the procedure to be performed. FIG. 9 is a schematic diagram showing a state of the real data area 7 when the fixed-length memory block area secured in the real data area 7 of FIG. 1 is changed to a variable-length area. 10 is a diagram showing a new pointer and chain when the fixed-length memory area 11 at the memory address 612 shown in FIG. 7 is released. FIG. 11 is allocated as a fixed-length data storage area by the memory management means 4. It is a flowchart explaining the general | schematic procedure which open | releases a fixed length memory area.

  First, the memory management system X according to the present embodiment will be specifically described with reference to the block diagram of FIG. FIG. 1 is a hardware configuration diagram of the present invention, and shows an example in which a program 3 is running on an OS 2 controlled by the CPU 1. When a job requiring memory is generated by the program 3 or the OS 2, the request is sent to the CPU 1 and sent from the CPU 1 to the memory management means 4 as a memory request (allocation request, release request). The memory management means 4 is constituted by, for example, a conventionally known memory controller. In response to the memory request from the CPU 1, the memory management unit 4 allocates and releases the requested memory size area in the actual data area 7 of the memory 5. In that case, in order to execute a free area search process in the real data area 7 which is an example of pre-processing, management related to the memory usage status of the real data area 7 managed in the management area 6 provided in the memory 5 is performed. Information (management table) is referred to by the memory management means 4.

  In this memory management system X, the memory 5 is managed based on the variable-length memory management system. Therefore, when an allocation / release request for the memory is issued from the CPU 1, the management area is controlled by the conventional variable-length memory system. Management data is created in 6 and the memory usage status of the actual data area 7 is managed. That is, the actual data area 7 is an entire variable length memory area. Therefore, the operation and configuration of the memory management means 4 and the management area 6 for performing variable-length memory management of the memory 5 can be realized using conventional techniques, and the description thereof is omitted.

  Here, while performing variable-length memory management of the memory 5, a peculiar point in the memory management system X of the present invention will be described with reference to FIGS. 2 and 3. FIG. 2 is a table showing the contents of the management table of the fixed-length memory area according to the memory management system X of the present invention. In particular, when data processing is performed by an information processing device, an input / output device, an image processing device, or the like, data having a specific fixed data size may be frequently processed. For example, data transferred and processed via an input / output buffer having a fixed data size has a fixed length such as 256 bytes or 1024 bytes. In the case of image processing, fixed-length data is also processed for each line.

  As described above, the fixed data size that is frequently processed is often determined depending on the type of device. Therefore, by processing the data of that size as a fixed length in the area of the fixed-length memory block described later, the variable length can be changed. In addition to improving the conventional problems associated with the memory management system, the conventional problems associated with the fixed-length memory management system can be improved by processing data suitable for the variable-length memory management system in a variable length.

  Here, in the image processing apparatus, the information processing apparatus, and the like using the memory management system X of the present invention, the memory management system is assumed assuming that 1024 bytes and 256 bytes of fixed-length data are frequently processed. X will be described. The fixed-length memory area management table 10 shown in FIG. 2 is provided in the management area 6 and includes a “fixed data size” of data to be managed as a fixed length and an area created as a variable-length data area. The total number of fixed-length memory areas that have the same size (corresponding to the specified data size) as the fixed data size that exists in the memory, and unused and unallocated free fixed areas among the multiple fixed-length memory areas It manages the “free number” of the long memory area and the “start address” indicating the address of the first free fixed-length memory area. The elements managed by the management data 10 are not intended to be limited to the above elements. In the following example, it is assumed that management is performed on fixed-length data of 1024 bytes and 256 bytes.

  In the example shown in FIG. 2, with respect to the fixed data size of 1024 bytes, 32 is shown in the total number column, so the fixed length memory block area consisting of 32 fixed length memory areas of 1024 bytes is assigned to the real data area 7 (FIG. 1). ) Means that it can be created, and since the empty number field and the top address field each indicate “0” in decimal notation, the above fixed-length memory block has not yet been created. Means. The same applies to a 256-byte fixed-length memory area, but since 64 is shown in the total number column, a fixed-length memory block area composed of 64 fixed-length memory areas can be created. Although details will be described later, when both the empty number field and the head address field are not “0”, it means that a fixed-length memory block area to which fixed-length data is allocated has already been created.

  Next, referring to FIG. 3 and FIG. 4, a procedure for the memory management means 4 (FIG. 1) to perform fixed-length memory management for data of a specific fixed data size using the variable-length memory management method. An outline will be described. FIG. 3 is a schematic diagram showing the state of the actual data area 7 when data is sequentially allocated to the actual data area 7 (FIG. 1). FIG. (B) shows an allocation request for variable length data. Based on the request, (b) divides the empty area A into the empty area A, and allocates the variable length data area AA. The state where the free area B is secured is shown.

  FIG. 3C shows a request for allocation of fixed-length data of 1024 bytes registered in advance in the management table 10 after the actual data area 7 is in the state shown in FIG. When there is no area to be allocated, the empty area B is divided into two, and a 1024 byte × 32 area is created as the area BB1 of the fixed-length memory block, and the remaining area is reserved as the empty area C. FIG. 3 (d) shows a state in which a memory allocation request for 256-byte fixed-length data registered in advance in the management table 10 is received, and when there is no area to allocate it, the free area C is divided into two. The state of the real data area 7 when 256 bytes × 64 areas are allocated as the area CC of the fixed-length memory block and the remaining area is secured as the empty area D is shown. Note that the areas BB1 and CC of the fixed-length memory block are each managed by a variable-length memory management system.

FIG. 4 is a flowchart showing a schematic procedure for allocating the variable length data area AA and the fixed length memory block area BB1 or CC shown in FIG. 3 by the memory management means 4 (FIG. 1). In the figure, S1, S2,... Indicate processing procedure numbers (step numbers). The process starts from S1.
Now, when an allocation request for a certain size of memory is issued from the CPU 1 to the memory management means 4 in S1, the management table 10 (FIG. 2) is searched by the memory management means 4 in S2, and the requested allocation size is determined. It is determined whether or not it is registered as a fixed data size for performing memory management by the memory management method X. If the determination at S3 is made and the size of the data requested for allocation is not registered, the process branches to S8 and a variable length data area (for example, a variable length data area, for example) based on the normal variable length memory management method. AA) is secured in the actual data area 7 (see FIG. 3B).

  If it is determined in S3 that the size of the data requested for allocation is registered as a fixed data size (for example, 1024 bytes) for performing memory management according to the present invention, the processing procedure thereafter proceeds to S4. In S4, it is determined whether or not a fixed-sized memory block area of that size has already been created, that is, whether or not a fixed-sized memory block area corresponding to the requested fixed data size exists in the memory 5. Is done. This determination is made based on the number of empty spaces in the management table 10 and the value of the start address. That is, if a value other than “0” is written in the empty number and head address fields, it is determined that a fixed-length memory block area exists, and if “0” is written, a fixed-length memory block is determined. It is determined that the area exists. When it is determined in S4 that the fixed-length memory block BB1 has already been created as shown in FIG. 3C, the process proceeds to S6. If it is determined that it has not yet been created, the process branches to S5 to create a fixed-length memory block area BB1 (see FIG. 3C), and then proceeds to S6.

  In S6, a fixed-sized memory block area starting from the head address stored in the management table 10 is requested in the fixed-sized memory block area BB1, which already exists, or in the fixed-sized memory block area BB1 newly created in S5. Allocated as a memory storage area for data. Due to the allocation of the fixed-length memory area, the number of empty fixed-length memory areas in the fixed-length memory block area BB1 and the start address vary. For this reason, chain replacement is performed in S7, which will be described later, and the state information of the free fixed-length memory area is updated to the latest state at the same time as the free number and head address of the management table 10. Although not shown in the flowchart, when an allocation request is processed and a fixed-sized memory area is allocated, the address of the allocated memory area is returned from the memory management means 4 to the requesting CPU 1 to complete the allocation process.

  Next, see FIG. 5 for details of the procedure in S5 of FIG. 4, that is, the creation procedure when the fixed-size memory block area BB1 of the fixed data size registered in the management table 10 has not yet been created. To explain. FIG. 5 is a schematic diagram for explaining the procedure for creating the fixed-length memory block area BB1, where (a) shows the contents of the management table 10, and (b) shows the fixed table shown in FIG. 3 (c). The long memory block area BB1 and its details are shown.

  FIG. 5A shows that a part of the management table 10 shown in FIG. 2 and that 32 pieces of fixed-length data having a fixed data size of 1024 bytes can be created. Until BB1 is created, “0” is displayed in the empty number column, and “0” is also displayed in the head address column. The memory management means 4 (FIG. 1) that has received the 1024-byte memory allocation request has the 1024 size registered in the management table 10 (Yes in S3), and a fixed-length memory corresponding to that size (1024 bytes) When it is determined that the block area BB1 does not exist (No in S4), the area BB1 of the fixed-length memory block including the 32 1024-byte fixed-length memory areas 11 in the empty area B in FIG. Create (secure). When the memory address of each fixed-length memory area 11 is expressed by a decimal number, for example, it starts at the first address 611 and ends at the last address 642. Note that the addresses (addresses 611 to 642) here are addresses for easily explaining the present embodiment, and are addresses given every 1024 bytes, which are different from actual memory addresses. As an actual address, a physical address or a logical address space of the memory 5 represented by an absolute address or a relative address is used.

Since each fixed length memory area 11 is empty, the address 611 of the first free fixed length memory area 11 is written in the first address column of the management table 10. That is, the head address column of the management table 10 indicates the first free fixed-length memory area 11.
At present, all the fixed-length memory areas 11 are unused (empty). Therefore, the address of the next free fixed-length memory area 11, that is, the address 612 is written in the fixed-length memory area 11 at the first address 611, and similarly, in the fixed-length memory area 11 at the address 612. Is written with address 613. That is, an address indicating the (n + 1) th empty fixed length memory area 11 is written in the nth empty fixed length memory area 11. Then, since the last fixed-length memory area 11 at address 642 does not have a free fixed-length memory area indicated next, “0” is written. In this way, by writing the address of the next free area in the free area, if the address (pointer) indicating the next address written in the head address column of the management table 10 is sequentially followed, all A chain in which the empty fixed-length memory areas 11 are sequentially connected is completed. The end of the chain is a fixed-length memory area 11 having “0” as a pointer.
Thereafter, the number of free fixed-length memory areas 11 (currently 32) is written in the empty number column of the management table 10.
By following the procedure of S5 (FIG. 4), a fixed-length memory block area BB1 is created.
After that, since the allocation of S6 in FIG. 4 is performed, the empty fixed-length memory area 11 at address 611 is allocated as a data storage area. Therefore, when the chain is changed in S7 described later, the number of empty management tables 10 is changed. The column is rewritten to 31 pieces. Thereafter, in response to a request from the CPU 1 (FIG. 1), data is written at address 611 by the memory management means 4 (FIG. 1).

  Subsequently, when the fixed-length memory block area BB1 has already been created, that is, the procedure of S6 after it is determined in S4 of FIG. 4 that there is a fixed-length memory block area (Yes side of S4), FIG. A specific description will be given with reference to FIG. FIG. 6 is a schematic diagram for explaining the procedure for allocating the fixed-sized memory area 11 in the fixed-sized memory block area BB1, (a) shows the contents of the management table 10, and (b) shows the contents of FIG. 3 (c). The details of the fixed-length memory block area BB1 shown are shown.

  In the management table 10 of FIG. 6A, 32 fixed-length memory areas 11 of fixed-length data having a fixed data size of 1024 bytes are created, 10 of which are free, the first free fixed-length memory. It is indicated that the head address indicating the area 11 is 611. As described with reference to the flowchart of FIG. 4, when the memory management means 4 (FIG. 1) receives a 1024-byte memory allocation request, the first address indicated by the address written in the top address column of the management table 10 is always indicated. An empty fixed length memory area 11, that is, a fixed length memory area 11 at address 611 in this example, is allocated as a data storage area.

  Next, referring to the schematic diagram of FIG. 7, a pointer and chain replacement procedure (S7 in FIG. 4), which is an example of post-processing, after allocating the fixed-length memory area 11 at address 611 will be described. When the fixed-size memory area 11 at address 611 shown in FIG. 6 is allocated, the pointer (address 613) that has been written in the fixed-length memory area 11 at address 611 in FIG. It is written in the head address column of the management table 10 shown in (a). That is, the pointer shown in the head address column is rewritten from address 611 to address 613. As can be seen from a comparison between FIG. 6 and FIG. 7, the pointer (address indicating the next free area) written in the free fixed-length memory area 11 at address 613 and thereafter is not changed. The pointer that has been written in the fixed-length memory area 11 at the address 611 is lost due to the written data, but the pointer is transferred to the head address column of the management table 10 before it is lost due to the data. At this time, since the vacant number of the management table 10 is decreased by 1, the total number of vacant numbers is rewritten from 10 to 9. In this way, the pointer and chain are replaced after the assignment in S6 of FIG.

Next, a schematic procedure for releasing the fixed-length memory area allocated as the data storage area by the memory management means 4 will be described with reference to FIGS. Here, FIG. 8 releases the fixed length memory area 11 of the head address 711 in the fixed length memory block BB3 among the three fixed length memory block areas BB1 to BB3 created in the actual data area 7 of the memory 5. It is a schematic diagram for demonstrating a procedure, (a) shows the content of the management table 10, (b) shows the fixed-sized memory block area | region BB3 and the detail of the content. FIG. 8A shows that 32 pieces of fixed length data having a fixed data size of 1024 bytes can be created, which is a part of the management table 10 shown in FIG. Further, as shown in FIG. 8B, the fixed-length memory block BB3 (configured by addresses 711 to 742) is in use only by the fixed-length memory area 11 at the address 711, and the other 31 fixed lengths. The memory area is empty. FIG. 9 is a schematic diagram showing a state of the actual data area 7 when the fixed-length memory block area secured in the actual data area 7 of FIG. 1 is changed to a variable-length area.
First, in S11, when the CPU 1 issues an release request for designating the address 711 to the memory management means 4 (FIG. 1) and releasing the fixed length memory area 11 of the address 711 in the fixed length memory block BB3. , S12, the fixed length memory area 11 of the designated address 711 is released. Thereafter, in S13, whether or not all the fixed-length memory areas 11 in the fixed-length memory block BB3 have been released, that is, all the fixed-length memory areas 11 in the fixed-length memory block BB3 are empty (unused). It is determined whether or not there is. Such a determination is made based on the numerical value in the empty number column of the management table in FIG. 8A before and after opening. In this example, since only the fixed-length memory area 11 at the address 711 of the fixed-length memory block BB3 is in use, all the fixed lengths in the fixed-length memory block BB3 are released by releasing this fixed-length memory area 11. If it is determined that the memory area has been released, the process proceeds to S14. If it is determined No in step S13, the process proceeds to S16, and the chain is replaced as described later.

If it is determined in S13 that all the fixed-length memory areas 11 are released, then in S14, there are two or more fixed-length memory blocks in which all the fixed-length memory areas 11 are released in the actual data area 7. It is judged whether or not. For example, as shown in FIGS. 9A and 9B, when there is a fixed-length memory block BB2 secured in the actual data area 7 with all the fixed-length memory areas being open, If it is determined in S13 that all fixed-length memory areas in the fixed-length memory block BB3 are released, there are two fixed-length memory blocks BB2 and BB3 in which all the fixed-length memory areas are released. Therefore, in this case, the process proceeds to S15. If there are not two or more fixed-length memory blocks in which all fixed-length memory areas are released, the process proceeds to S16.
In S15, either the fixed-length memory block BB2 or BB3 is changed to a variable-length memory area. That is, the fixed-length memory block area reserved for allocating the fixed-length memory area is restored to the original variable-length memory area. FIG. 9C shows the state of the actual data area 7 after the change. Note that the area to be changed to the variable-length memory area may be either the fixed-length memory block BB2 or BB3. However, in the fixed-length memory block BB2 in which all the fixed-length memory areas have been previously released, the area is already changed. Since the chain is changed, it is desirable to change the fixed-length memory block BB3 to a variable-length memory area. This eliminates the need to re-chain the fixed-length memory block BB3, thereby reducing the processing burden.

  By the way, when all the fixed-length memory areas are released, it is possible to immediately change the area of the fixed-length memory block to the original variable-length memory area. For example, a plurality of fixed-length memory areas in the fixed-length memory block BB3 can be considered. If a fixed data size data allocation request is made immediately after the fixed length memory area is all released and the fixed length memory block BB3 is changed to the original variable length area, a plurality of fixed length memory areas are again stored. It is necessary to newly secure a fixed-length memory block BB3 consisting of If such a process is repeated, the size of the fixed-length memory block BB3 is very large, and there is a problem that the processing load for changing to the variable-length area and re-reserving the fixed-length memory block increases. Therefore, in this memory management method X, unlike other memory management methods, even when all the fixed-length memory areas in the fixed-length memory block BB2 are released, there is no other such fixed-length memory block. Left the fixed-length memory block BB2 without changing it to a variable-length memory area, and all the fixed-length memory areas of the fixed-length memory block BB3 were released, so that all the fixed-length memory areas were released. Only when there are two or more fixed-length memory blocks, one fixed-length memory block is changed to a variable-length area. As a result, there is at least one fixed-length memory block in which the fixed-size memory area is completely released in the actual data area 7 (FIG. 1), which causes a problem that the processing load described above increases. The memory usage efficiency can be improved.

  When it is determined No in S13 or S14 and the process proceeds to S16, the chain is replaced after the fixed-length memory area at the address designated by the CPU 1 is released in S16. Here, with reference to FIG. 10, the procedure for changing the pointer and chain when the fixed-size memory area No. 612 shown in the fixed-size memory block BB1 (see FIG. 7) that has been used up to now is released will be described. To do. FIG. 10 is a diagram showing a new pointer and chain when the 612 fixed-length memory area 11 shown in FIG. 7 is released. When the fixed-size memory area 11 at address 612 is released by the memory management means 4, the pointer written in the head address column of the management table 10 shown in FIG. 10 (a) is rewritten from address 613 to address 612. It is done. In other words. The address of the released fixed-sized memory area 11 (address 612) is written as a pointer in the head address column of the management table 10. Then, the address 613 stored in the leading address field is written as a pointer in the fixed-length memory area 11 at the released address 612.

As described above, when a memory allocation request is received from the CPU 1, only the address (pointer) written in the head address column of the management table 10 is notified, and the memory allocation pre-processing is completed, and the memory management speed is increased. Can be achieved.
When the fixed-sized memory area 11 is allocated as a data storage area, the subsequent processing is only to transfer the pointer held by the allocated fixed-sized memory area 11 to the head address column of the management table 10. One action is enough. When the fixed-sized memory area 11 is released, as an after-processing, the address of the released fixed-sized memory area 11 is written as a pointer in the head address column of the management table 10, and the released fixed-sized memory area 11 11, the two operations of transferring the pointer that the head address column of the management table 10 had so far are all necessary. That is, only by changing the first pointer of the chain or the first and second pointers, the replacement of the chain indicating the free fixed-length memory area 11 is completed, and the memory management can be further speeded up.

Although not illustrated and described, the 256-byte fixed-length memory block area CC shown in FIG. 3D is also managed in the same procedure as the fixed-length memory block areas BB1 to BB3 described so far.
Up to now, 1024 bytes or 256 bytes of fixed-length memory block area BB1 or the like and CC have been managed by the variable-length memory management method. Furthermore, in the fixed-length memory block area BB1 or CC, an empty fixed-length memory area However, it goes without saying that the present invention is not limited to these examples and numerical values.
The fixed length of 1024 bytes or 256 bytes varies depending on the apparatus in which the present invention is implemented, and may be, for example, 2048 bytes, 512 bytes, or other fixed data sizes. Furthermore, these fixed data sizes may be set to a size at which memory allocation requests are frequently issued in the apparatus in which the present invention is implemented. Then, unlike the conventional fixed-size memory management method, a fraction is not generated between the required size and the memory use efficiency is not lowered.

  In order to explain the above embodiment in an easy-to-understand manner, the memory 5, the management area 6 and the real data area 7 are assumed to be physical memories, and the actual addresses are shown by specific addresses. Needless to say, the present invention is applicable not only to memories but also to rewritable recording media such as hard disks, CD-RWs, DVD-RWs, DVD-RAMs, MOs, and MDs.

The block diagram which shows the hardware constitutions for implement | achieving the memory management system X of this invention. The table figure which shows the content of the management table of the fixed-size memory area which is produced in the management area 6 of FIG. 1, and concerns on the memory management system X of this invention. The schematic diagram which shows the state of the real data area | region 7 when data are sequentially allocated to the real data area | region 7 of FIG. 4 is a flowchart for explaining a general procedure for assigning variable length data and fixed length data shown in FIG. FIG. 4 is a schematic diagram for explaining a procedure for creating a fixed-length memory block area BB1, where (a) shows the contents of the management table 10, and (b) shows the area BB1 of the fixed-length memory block shown in FIG. Details of the contents are shown. FIG. 4 is a schematic diagram for explaining a procedure for allocating a fixed-sized memory area in a fixed-sized memory block area BB1, in which (a) shows the contents of the management table 10, and (b) shows a fixed-sized memory block shown in FIG. 3 (c). The details of the area BB1 are shown. The schematic diagram for demonstrating the post-process after allocating the fixed length memory area 11 of the memory address 611. FIG. Schematic for explaining a procedure for releasing the fixed-length memory area 11 at the head address 711 in the fixed-length memory block BB3 among the three fixed-length memory block areas BB1 to BB3 created in the actual data area 7 of FIG. Figure. FIG. 2 is a schematic diagram showing a state of a real data area when a fixed-length memory block area secured in the real data area in FIG. 1 is changed to a variable-length area. The figure which shows a new pointer and chain when the fixed-length memory area 11 of the memory address 612 shown in FIG. 7 is released. 7 is a flowchart for explaining a schematic procedure for releasing a fixed-length memory area allocated as a fixed-length data storage area by the memory management unit 4;

Explanation of symbols

1 ... CPU
2 ... OS
3 ... Program 4 ... Memory management means 5 ... Memory 6 ... Management area 7 ... Real data area 10 ... Management table 11 ... Fixed length memory areas A, B, C, D ... Empty areas AA ... Variable length data areas BB, BB1, BB2, CC: Fixed-length memory block area

Claims (2)

In a memory management method for changing an area of a fixed-length memory block composed of a plurality of fixed-length memory areas having a predetermined data size previously secured in a variable-length area on a memory to the original variable-length area,
When two or more fixed-length memory blocks are reserved in the variable-length area on the memory, all of at least two fixed-length memory blocks of the two or more fixed-length memory blocks reserved of the condition that the fixed-length memory area is opened, the fixed-length memory area either based on one of the fixed-length memory block the entire area of all the opened two or more fixed-size memory blocks A memory that is changed to a variable-length area, and when there is one fixed-length memory block in which all the fixed-length memory areas are released, the fixed-length memory block is not changed to the original variable-length area. Management method. The fixed-size memory area is chain-managed by executing the chain re-alignment with the allocation / release of the fixed-length memory area of the fixed-length block.
When two or more fixed-length memory blocks are secured in the variable-length area on the memory, in any one fixed-length memory block of the two or more fixed-length memory blocks secured in the variable-length area When the fixed-length memory area is all released, and there is no fixed-length memory block whose fixed-length memory area is completely released in addition to the one fixed-length memory block, the one fixed-length memory block If the fixed-size memory area of the block is not changed to the original variable-length area, and there is the fixed-length memory block in which the fixed-size memory area is completely released, in addition to the one fixed-length memory block, 2. The memory management system according to claim 1, wherein the fixed-length memory areas of the two fixed-length memory blocks are changed to the original variable-length areas before execution of the chain replacement.

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