JPH01109451A - Real memory management method - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to an information processing device, and in particular to a computer that realizes virtual memory by dividing a storage device into pages and using the pages as an allocation unit. This invention relates to a real memory management method suitable for improving the performance of operating systems.

[Conventional technology]

Conventional operating systems that manage virtual memory divide all real storage devices into pages of the same size and use these as the unit of allocation, so they do not give much consideration to allocating pages from multiple consecutive real storage devices. For example, Hi-Tac Manual "System Product VO33/ESI Storage Design" (1985), PP28. As described, the area where pages need to be continuous is a V area where the address indicated by the virtual storage device and the address indicated by the real storage device match.
=R area, but this area requires a specific area to be reserved as a V=R reserved area at the time of system startup. =R There was a problem in that the reserved area deteriorated the utilization efficiency of real storage.

[Problem that the invention seeks to solve]

As mentioned above, in traditional operating systems,
Because the real storage device was divided into pages and each page was allocated, it was not possible to allocate multiple consecutive real storage device pages to arbitrary locations.

There has been a problem in that it is difficult to efficiently store data that needs to be continuous on a real storage device.

One way to solve this problem is to increase the page size, but this has drawbacks such as lack of compatibility with conventional methods and the tendency to waste real storage space.

An object of the present invention is to provide a real storage management method that efficiently allocates pages of a plurality of consecutive real oil storage devices without wasting storage devices while keeping the page size the same as before.

[Means for solving problems]

The purpose of the above is to create a table that manages the real storage device page by page, a bit that indicates whether each page of the real storage device is treated as multiple consecutive pages, and a bit that indicates whether the page is treated as multiple consecutive pages. , a reference count table is provided to count how many pages are in use as individual pages, and when allocating one page, the value of the reference count table is increased by +1.
When allocating and releasing one page, the value in the reference count table is decreased by 1, and if the value in the reference count table becomes 0 at that time, the bit indicating the expansion size indicates that it is the expansion size. This is achieved by providing means for indicating and releasing the

[Effect]

The bit that indicates whether multiple consecutive pages are treated as a single page or not.
Or, it indicates whether the page is treated as a continuous page. Based on this information, it is possible to decide in what unit this page should be allocated or released.

A reference count table that shows how many pages are used among multiple consecutive pages.

If a page in it is not used at all by itself, it shows 0, +1 every time a page in it is allocated as a single page, and -1 every time it is freed.
1 will be given. As a result, even if a page among consecutive pages is repeatedly allocated and released independently, it can be determined whether or not it can be treated as a continuous page just by looking at the value in the count table. Also, by looking at this reference count table, you can see how many single pages are being used, so you can check other reference count tables to find free single pages, and find out how many pages are being used. You can quickly create consecutive empty pages by copying .

With these features, pages can be allocated and released in a timely manner, whether it is a single page or a series of pages, without wasting real storage space.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1, 2, 3, 4, 5, and 6.

In this example, one page (hereinafter referred to as a basic size page) is 4K113, and consecutive pages to be allocated (
Hereinafter, the number of pages (hereinafter referred to as extended size pages) is 4 pages.

FIG. 1 shows a configuration diagram of one embodiment. real memory bag r
11 are all divided and managed into basic-sized units called pages. The operating system 5 manages this real storage device by providing a real storage management table 2. This table has an extension size bit 20 that indicates whether the page's extension size is the basic size. The reference count table 3 counts how many pages of the corresponding basic size are in use. The operating system 5 has a real memory management routine 50 that manages real memory.
．． Basic size allocation routine 51 for releasing 1 page allocation, M size release routine 52. Extended size allocation routine 53. It has an extended size release routine 54.

FIG. 2 shows the real storage device a! in this embodiment. 3 shows a configuration diagram of the management table of (2). The real memory bag fil contains 1 if the page is used as an extended size,
Extended size bit 20 indicating 0 if used as the base size and 1 if the page is used. Used bit 2 indicates 0 if not used
1 and a management table chain pointer that chains tables of the same type depending on whether they are in use or unused, and whether they are expanded or basic size.

However, in the case of extended size, only the table of the first basic size page is chained.

The reference count table 3 is provided for each extended size page, and indicates how many basic size pages are used as basic size pages. Its value is O if no base size pages are used.
4 is shown when all pages of 1 basic size are used. Management table top chain table 4 is
The management table chain pointer 22 has a chain to the top table of each chain classified according to whether it is in use or unused and whether it is expanded size or basic size. FIG. 3 shows details of the basic size allocation routine 41. FIG. 4 shows details of the basic size release routine 42. FIG. 5 shows details of the extended size allocation routine 43. FIG. 6 shows details of the extended size release routine.

Next, the operation of this embodiment is shown in FIGS. 2, 3, and 4.

This will be explained using FIGS. 5 and 6.

When allocating a page of the basic size, first check whether there is an unused chain of the basic size in the first chain table 4 of the management table, and if there is, that page is allocated. All you need to do is to allocate it, so set the used bit 21 of that page to 1, add 1 to the value of the corresponding reference count table 3, re-attach the management table pointer chain 22, and make it the basic size and in use. In addition, if there is no unused chain in the basic size, check whether there is an unused chain in the extended size in the management table first chain table 4, and if there is, check the first chain in the extended size. All you have to do is allocate one page of the basic size, so take that extended size page from the chain in use, set all the extended size pins 20 of all the basic size pages to O, and set the first basic size page among them. Set the used bit 21 of the page to 1, increase the value of the corresponding reference count table 3 by 1, connect the management table chain pointer 22 to the chain in use in the basic size, and set the management table chain pointer of the other three basic size pages. Connect 22 to the unused basic size. Furthermore, if there is no unused space in the expanded size, the capacity of the real storage device 1 is insufficient, and this is notified.

To release a basic size page, first set the used bit 21 of that page to O, re-attach the management table chain pointer 22, and change the basic size from the chain currently in use to the basic size. Connect the unused chain to the next corresponding reference count table 3 value -
Do 1. At that time, if the value of reference count table 3 becomes O, this indicates that the four pages around this can be used as expanded size pages, so the corresponding four pages
Set the extended size bit 20 of the two pages to 1, reattach the management table chain pointer 22 of these pages, take out the four pages at the basic size from the unused chain, and set the first page to the extended size from the unused chain. Connect to.

When allocating an extended size page, as shown in Figure 5, first check whether there is an unused extended size chain in the first chain table 4 of the management table, and if so, allocate that page. If so, set the four used bits 21 of that page to 1, re-attach the management table chain pointer 22 of the first basic size page, take out the unused ones in the expanded size, and do. Also, if there is no unused expanded size, search reference count table 3,
Find the one with the smallest value.

Next, it is possible to search for an unused basic size page in the management table top chain table 4, and move the used basic size page among the extended size pages with the smallest value in the reference count table 3. Find out if there is one. If there are no unused basic size pages that can be moved, the capacity of real storage device 1 is insufficient, and this will be notified. If there are, the basic size pages in use will be moved and the unused pages will be moved. Use extended size pages to make them. To do this, reset the management table chain pointer 22 for the necessary number of unused basic size pages, connect them to either the basic size unused chain or the used chain, and set the used bit 21 of those pages to 1. and counts up the value of the corresponding reference count table 3. Then, copy the contents of the basic size page in use in the expanded size page to that page. Next, use the management table chain pointer of the basic size page in use in this expanded size. Extract from the middle chain, set the extended size bit 20 of this extended size page to 1, set the used bit 21 to O, set the reference count table 3 to O, and expand the management table chain pointer 22 of the first basic size page. Connect to the chain in use by size and allocate a page of this expanded size.

To release a page of expanded size, as shown in FIG. Make it.

In this way, by providing the bit indicating the extended size and the reference count table, it is possible to use up to the capacity of the real storage device, and both the extended size and the basic size can be used with the same efficiency.

Pages can be allocated and released. Furthermore, even if there are no extended-sized pages and there are excess basic-sized pages, you can quickly create extended-sized pages.

〔Effect of the invention〕

According to the present invention, the usage efficiency of the real storage device is such that if it is a single page, it is used up to the real storage capacity limit, and if it is consecutive pages, it is used up to the capacity equal to the number of consecutive pages - 1. Therefore, the usage efficiency is sufficiently high compared to the conventional method, and if the storage capacity is sufficient, allocation can be performed at the same speed for either a single page or consecutive pages. Also, even if there is insufficient storage capacity and unused individual pages exist in fragments, the values in the reference count table will tell you how to move the individual pages in order to create continuous pages. Since you know what's good, you can create consecutive pages.

[Brief explanation of the drawing]

Figure 1 is a configuration diagram of an embodiment of the present invention, Figure 2 is a configuration diagram of a management table, Figure 3 is a flowchart for allocating a basic size page, and Figure 4 is a diagram for releasing a basic size page. FIG. 5 is a flowchart for allocating an extended size page, and FIG. 6 is a flowchart for releasing an extended size page. 1... Real storage device, 2... Real storage management table, 3
...Reference count table, 4...Management table top chain table, 20...Extension size bit, 21.
...Used bit, 22...Management table chain pointer, 50...Operating system, 51...
- Basic size allocation routine, 52... Basic size release routine, 53... Extended size allocation routine, 5
4...Yu 1 Figure Z Figure 3 Figure 5 Mouth'fJ 6 Figure

Claims (1)

[Scope of Claims] 1. In an information processing device that uses a virtual storage method in which a storage device is divided into pages of the same size, a table that manages the usage status of each page of a real storage device;
a bit indicating the expansion size for each page of real storage;
For each multiple page of real storage device, there is a reference count table that shows how many pages among the multiple pages are being used as a single page, and when allocating one page, the corresponding reference count table shown above. When a page is released, the corresponding value in the above reference count table is set to -1, and when the value in the corresponding above reference count table becomes 0, the above extended size is used. A real memory management method characterized by providing a means for indicating that a bit indicating an expanded size is an expanded size and releasing it.