JP3094477B2 - Virtual storage management method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a virtual storage management system in an electronic computer system.

[0002]

2. Description of the Related Art In virtual memory management, a logical space is subdivided into segments and pages, and mapping is performed with a memory on a main memory. This mapping is performed by a control table called a segment table and a page table provided for each job.

In the conventional virtual memory management method, a page table is created at the time of securing the first memory in order to improve the memory efficiency on the main memory, and then the memory is expanded when the memory is secured and the page table becomes insufficient. I have.
The method of expanding the page table is to secure another area of the size to be expanded, copy the contents of the current page table to the newly secured area, and use the copied area as a new page table. Things.

[0004]

However, in the above-described conventional virtual storage management method, the page table is expanded stepwise as the memory reservation of the job increases.
There is a problem that overhead is large.

[0005]

[Means for Solving the Problems ] To solve the above problems
Therefore, the virtual storage management method of the present invention
Use to store the number of used pages in memory for each job
Page storage means, and the memory of the memory during job execution.
The number of used pages that fluctuates each time it is allocated and released
When the number of pages is maximum, the number of pages is used for the job
Number of pages to be stored in the memory for each segment.
Means for acquiring the number of pages,
Statistics based on the quantity of the pages listed
To estimate the number of pages used for each job segment.
Means for estimating the number of pages for use and the estimated number of used pages
Calculate the page table length and create the page table.
Page table creating means, and the page table
The file creation means determines the size of the page table once created.
The job is launched to hold it without stretching
When the page table is created,
I do.

[0006]

Since the present invention is configured as described above, the size of the page table is predicted from the past usage amount of each segment by collecting statistics on the memory usage amount of the job for each segment, and starting the job. At times, a page table is created in advance, and the number of times of expanding the page table can be reduced.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of the present invention. In FIG. 1, reference numeral 1 designates the number of pages at the time when the number of pages fluctuating by securing and releasing memory during a job execution becomes maximum as the number of used pages of the job in the used page number storage means 2. The used page number acquiring means 2 is set on a storage medium such as a main memory or a disk by the used page number acquiring means 1, and used page number storing means for storing the number of used pages for each segment for each job. Is used page number estimating means for estimating the maximum value of the number of pages belonging to the job which fluctuates during the execution of the job from the used page number statistical information stored in the used page number storing means 2 at the time of starting the job. The page table creation means 5 for creating a page table based on the number of pages notified from the page number estimation means 3 and the page table When the number of pages sent from the di-number prediction means 3 is equal to or greater than the reference value, a memory load page table creation means for creating a page table in place of the page table creation means 4.

Next, the operation of the virtual storage management system configured as described above will be described.

The used page number acquiring means 1 is executed when a job is started, when a memory reservation request is issued from a job, when a memory release request is issued from a job, and when a job is terminated. To determine the number of used pages, for example, a used page number counter (not shown) and a maximum used page number counter (not shown) are used for each segment. The page number counter is cleared to 0. When a memory reservation request is issued from a job, the used page counter is incremented by the number of reserved pages requested for each segment. At this time, the used page counter of each segment is compared with the maximum used page counter, and if the used page counter is larger than the maximum used page counter, the value of the used page counter is used to the maximum. Set to the page number counter. When a memory release request is issued from a job, the used page counter is decremented by the number of released pages requested for each segment. After the job is completed, the value of the maximum used page number counter of each segment is set in the used page number storage unit 2.

FIG. 2 is a control table 1 of the used page number storage means 2.
FIG. 3 is a diagram for explaining an example of a configuration of a zero. 11 is a control table 10
, The number of startups of the program having the program name 11, and the in-segment used page entry 13 for storing the number of used pages in each segment. The used page entry 13 in the segment includes the past 16
The used page number entries for storing the number of used pages for 16 times are 16 entries from No. 0 to No. 15. When the used page number acquiring means 1 sets the number of used pages, the following procedure is performed. First, the control table 10 of the used page number storage unit 2 corresponding to the program name of the job is searched, and the control table 10 is searched.
1 is added to the number of activations 12 of. Next, for the first entry 13 of the used page entry in the segment, the right 4 bits of the number of activations 12 in the control table 10 are converted into a numerical value to be the entry number of the used page number entry, and the used page corresponding to the entry number is used. The number of used pages acquired by the used page number acquiring unit 1 is set in the number entry.
In this manner, the same operation is performed for the second entry 14 and subsequent entries of the used page entry in the segment.

The used page number estimating means 3 is executed when the job is started, and obtains the control table 10 of the used page number storing means 2 corresponding to the program name of the job to be started. The control table 10 of the used page number storage means 2 stores the number of used pages of each segment when activated 16 times in the past in the corresponding used page entry 13 in the segment.
The average value of the number of used pages for 16 entries of the used page number entry 13 is calculated for each segment. The average value obtained by the above calculation is used as the estimated number of pages to be used, and is notified to the page table creating means 4. The page table creation means 4 secures a page table area by calculating a page table length that satisfies the expected number of used pages from the expected number of used pages for each segment of the job notified from the used page number estimation means 3. , Initialize the area for the page table. Memory load page table creation means 5
Secures a page table area in place of the page table creation means 4 when the memory usage rate of the system is equal to or more than the reference value. When the predicted number of used pages for each segment of the job notified from the used page number prediction unit 3 is equal to or larger than a preset reference value, the reference value is adopted as the page table length to secure a page table area, Initialize the area for the page table.

[0012]

As described above, according to the present invention,
By predicting the number of pages used for each segment of the job upon job startup and reserving the page table in advance, the number of decompression processes that occur when reserving memory for the page table can be reduced, so that system overhead is reduced. Has an excellent effect that it can be reduced. In addition, when the memory usage rate of the system is high, the size of the page table secured for job activation is suppressed to within the reference value, so that when the memory load is on, the main storage can be used efficiently. There is also an excellent effect.

[Brief description of the drawings]

FIG. 1 is a block diagram of an embodiment of the present invention;

FIG. 2 is an explanatory diagram showing a configuration example of a control table in a page number storage unit of the present invention.

[Explanation of symbols]

 1 used page number acquisition means, 2 used page number storage means, 3 used page number prediction means, 4 page table creation means, 5 memory load page table creation means.

Continuation of the front page (56) References JP-A-63-113740 (JP, A) JP-A-62-241050 (JP, A) JP-A-64-241050 (JP, A) JP-A-3-240849 (JP) JP-A-2-12339 (JP, A) JP-A-62-79549 (JP, A) JP-A-3-147042 (JP, A) JP-A-4-213132 (JP, A) 2-304655 (JP, A) JP-A-60-8960 (JP, A) JP-A-3-91046 (JP, A) JP-A-63-76033 (JP, A) JP-A-4-153848 (JP, A) A) JP-A-2-196352 (JP, A) JP-A-3-25645 (JP, A) JP-A-62-237547 (JP, A) JP-A-1-1755651 (JP, A) JP-A-2 -43632 (JP, A) JP-A-2-132538 (JP, A) JP-A-4-65725 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G06F 12/08 G06F 12/10 G06F 9/46

Claims (2)

(57) [Claims] 1. The method according to claim 1, wherein the number of used pages of each segment is determined by a plurality of pages.
Used page storage means for storing in a memory for each job, and each time the memory is secured and released during job execution
When the number of pages used fluctuates
The number of used pages is defined as the number of used pages of the job.
Means for acquiring the number of pages stored in the memory for each segment
When starting a job, a plurality of files stored in the memory
From the statistical information based on the number of pages used,
Used page number prediction means for estimating the used page number for each application
And the page table length is calculated from the predicted number of used pages.
To create a page table
And the page table creation means includes a page table once created.
To keep the cable size without stretching it.
Creates the page table when the job is started
A virtual storage management method. 2. The system according to claim 1, wherein said page table creating means includes a system.
If the memory usage of the
If so, compare the expected number of pages with a threshold
And adopt the smaller one of them
2. The virtual recording method according to claim 1, wherein
Memory management method.