JPS63192145A - Page management system - Google Patents

Abstract

PURPOSE:To speed up garbage collection GC and to improve the availability of a memory by writing priority deciding information in a priority deciding information area for page control and using said priority deciding information and a priority table to manage pages. CONSTITUTION:When page data is transferred between a real memory space area 12 and a virtual memory space area 14, the priority deciding information on a page frame table 10 via a priority deciding information setting part 20. If a usable physical page area is not obtained, an allocatable physical page is detected by means of the priority deciding information and the information on a priority table 18. Thus a physical page is allocated according to said priority and therefore the page to be genuinely saved can be saved precedingly as much as possible. Thus it is possible to perform GC processing at a high speed and also to ensure the effective application of the area 12.

Description

[Detailed Description of the Invention] [Summary] Garbage collection (hereinafter referred to as GC) performed in page management of a virtual storage system. By introducing the situation determination process, only the garbage portion remaining in the memory is saved to the virtual storage space area as soon as possible, thereby speeding up the GC and improving the efficiency of memory use.

[Industrial application field]

The present invention relates to a page management system, and more specifically, to a page management system that can perform GC processing according to garbage portions to be saved to an external storage unit.

Some information processing devices use a virtual storage system as their storage system. In this virtual memory system, the CPU uses data that has been moved from the virtual memory space area to the real memory space area, and evacuates the outdated data part to the virtual memory space area in page units and stores it in the real memory space. It uses a page management system (LPU) that uses space as effectively as possible.

[Conventional technology]

FIG. 7 shows a virtual storage system employing a conventional page management method. In this figure, 30 is a CPU, 32 is a main memory control unit (MSC), 34 is a page management unit, and 36 is a
is the main memory (MS), 38 is the output processor (IO
P), 40 is a page file. The page management method in this system is as follows. When the CPU 30 wants to access the main storage device 36, the CPU 30
30 requests data access to the main memory controller 32 (Sl in FIG. 8). The main storage control device 32 requests the page management unit 34 to check whether the requested page exists on the main storage device 36 (32 in FIG. 8).
. Page frame table (see Figure 10) [V: Physical page valid display bit, FX double page fixed bit, F
T: Failure page bit, R: Copy of key storage reference bit, PNO: Process number using the page,
LpApR: Logical page address] and if the page exists on the main storage device 36 (Y of 83 in FIG.
ES), transfers the data requested for access to the CPU 30 (38 in FIG. 8). If there is no page that corresponds to the access request, search for a physical page with ■ = 0.
9) If there is no such area, refer to the R bit and save the page to the page file 40 to free up that area (512 in FIG. 9), and then allocate that area (
5ll in FIG. 9), and if there is a physical page, the physical page is allocated (511 in FIG. 9), and it is determined whether it is necessary to input data from the page file 40 (511 in FIG. 9). 85 in FIG. 8), and if it is not necessary, transfer the data of that physical page to the CPU 30 (38 in FIG. 8). If necessary, the main memory controller 32 inputs data from the page file 40 to the input/output processor 3.
8 (36 in Figure 8). Then, the data of the page file 40 is transferred to the main storage device 36 (37 in FIG. 8), and also transferred to the CPU 30 (38 in FIG.
).

The page management method described above is also used when using high-level languages. High-level languages require special processing called GC processing due to their nature. In other words, in high-level languages, unused data exists scattered among the data in the real memory space area, which hinders effective use of memory, so the unused data is transferred to the virtual memory space area. GC processing is performed to save the data.

[Problem that the invention seeks to solve]

If the above-mentioned LRU processing is simply used in the GC processing as described above, that is, if the LRU processing is simply performed without considering the state of the unnecessary data,
There is a high risk that even necessary pages that should not be left in the real memory space area will be saved to the virtual memory space area. Therefore, a so-called thrashing phenomenon occurs in which such a page must be returned to the real memory space area again after that, which not only delays GC processing but also prevents efficient use of memory.

The present invention was created in view of such problems, and an object of the present invention is to provide a page management method that can achieve high-speed GC processing and more efficient memory use.

[Means for solving problems]

FIG. 1 shows a block diagram of the principle of the present invention. In this figure, 10 is a page frame table, which has a priority determination information area 101 etc. necessary for page search, and this priority determination information area 10. During page management, priority determination information, such as the GC flag and SP flag, is written from the priority determination information setting section 20 provided in the page management means 16. 18 is a priority table provided in the page management means 16. Control of data transmission and reception in page units between the real memory space area 12 and the virtual memory space area 14 is performed using the information in the priority determination information area and the priority table 18 in which the pointer specifies the page information. The management means 16 performs this.

[For production]

Priority determination information in the page frame table 10 is written in advance by the priority determination information setting unit 20 when transferring page data between the real memory space area 12 and the virtual memory space area 14 .

Then, when no usable physical page area is found,
A physical page that can be allocated is found using priority determination information and priority table information.

Since physical pages are allocated according to such priority, it is possible to save only those items that are truly desired to be saved as early as possible. This enables faster GC processing and efficient use of real memory space.

〔Example〕

FIG. 2 shows a system configuration diagram implementing the present invention. This embodiment is based on the page management section 34 of the conventional system shown in FIG.
In addition, the GC front and rear half determination unit 50 (FIG. 2) (an example of the priority determination information setting unit 20 in FIG. 1) and the priority table 18 (FIG. 3)
) as well as a main memory (MS) 36 (see figure).
As shown in FIG. 4, the configuration of the page frame table IO provided in the real memory space area 12 (example of the real memory space area 12 in FIG. 1) is as shown in FIG. The characteristic part is that it is configured so that the following (example) can stand, and this characteristic part is used together with conventional components in the processing flow according to FIGS. Faster GC processing and more efficient main storage usage are achieved.

Figure 2 shows how this objective is achieved.

This will be explained according to the processing flows shown in FIGS. 8, 5, and 6.

CPU! The page you want to access from 10 is in main storage 3
6, the way to access that page is the same as before (St, S2 in Figure 8).
．． S3. S8).

If the page to be accessed does not exist in the main storage device 36, step S4 in FIG. 8, that is, the processing according to FIGS. 5 and 6 showing the main processing of the present invention is performed.

Proceed to step S9 in Figure 5, search for the physical page with ■ = 0, and if it exists (YES in stO in Figure 5)
, allocates an area to this (5ll in FIG. 5), and determines whether or not data input from the page file 40 (example of the virtual memory space area 14 in FIG. 1) is required, as in the conventional case ( 85 in FIG. 8), and if it is not necessary, the data requested for access is transferred to the CPU 30 via the main memory controller (MSC) 32 (38 in FIG. 8). vice versa,
If necessary, the main memory control unit 32 can create a page file 40.
After requesting the input/output processor (IOP) 38 to input data from the input/output processor (IOP) 38 (36 in Fig. 8), the data (page) from there is transferred and stored in the allocated area as described above (Fig. 8). 87), and is also transferred to the CPU 30 (S8 in FIG. 8).

In the determination at step SIO in FIG. 5, ■=0
If it is determined that there is no physical page, the following search process according to the present invention (820 in FIG. 5) is performed to create an allocable area.

The search process is performed according to what is shown in FIG.

First, the pre-GC/second-half determining unit 50 semi-determines whether the GC process is the first half or the second half of the GC, and as a result, if it is the first half, S
P flag - ○, if it is the second half, write SP flag = 1 to the page frame table 10 (in addition, at this time, the GC
Since it is inside, the GC flag is page frame table 10.
It is erected in ) (321 in Figure 6). And G
A corresponding priority table (see FIG. 3) is selected according to the GC front/half determination result by the C front/half determining unit 50 (322 in FIG. 5). Then, the 6th priority should be set to a=l.
323) in the figure, the page frame table 10 is searched by the pointer, and the priority a=l, in which the contents of the GC flag, SP flag, and R bit of the page frame table 10 pointed to by the pointer are set, that is, the priority table is It is checked whether the corresponding contents match or not, and a matching physical table is searched (824 in FIG. 6). If the physical table is found (YES at 325 in FIG. 6), select the physical table (326 in FIG. 6) and allocate it as the area to be used for the above access (step 5
5ll in the figure). The access processing process after the area is allocated in this way is the same as described above.

If the physical table is not found (325 in Figure 6)
No.), after setting a=a+l (327 in Figure 6)
, a>6 is determined (828 in FIG. 6). If not, the process advances to step S24 in FIG. 6 and a similar search process is performed. If the opposite is true, a selection failure is notified (330 in FIG. 6), and the page of the page frame table 10 indicating that the R flag is not set is transferred to the page file (virtual memory space) 40, as in the conventional technique. The data is evacuated, a necessary page area is created in the main storage device 36, and the process proceeds to step Sll in FIG. 5, where the process is similar to the conventional process.

In the above embodiment, the priority table has 6 levels of priority, but by adding the page rewrite flag in the page frame table to the priority setting, the number of priority levels can be increased. Physical table searches can be performed under multiple priorities.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to speed up the GC processing in page management and to make efficient use of the real memory space area.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of the principle of the present invention; FIG. 2 is a system configuration diagram implementing the present invention; FIG. 3 is a diagram showing a priority table; FIG. 4 is a configuration diagram of a page frame table of the present invention; 5, 6, 8, and 9 are diagrams showing processing flows, FIG. 7 is a conventional system configuration diagram, and FIG. 10 is a conventional page frame table configuration diagram. In FIGS. 1 and 2. 10 is a page frame table, 10 is a priority determination information area, 12 is a real memory space area (main storage device 36), 14 is a virtual memory space area (page file 4°), 18 is a priority table, 20 is a priority Degree judgment information setting section (QC front/back half judgment section 50)
It is. Patent Applicant: Fujitsu Ltd.
Figure Conventional I - 7% of the frame table? t 121 1st
Figure 0 Seven processes - Figure 5 Conventional system I! 4- Figure 7 Processing 7T: J- Figure 8 (A-2)

Claims (1)

[Scope of Claims] Page management means (16) that controls data transfer in units of pages between the real memory space area (12) and the virtual memory space area (14) while referring to the page frame table (10). A virtual storage system having: a priority determination information area (10_a) provided in the page frame table (10), a priority table (18), and a priority determination information setting means (20), During management, priority determination information is written in the priority determination information area (10_a) by the priority determination information setting means (20), and the priority determination information and the priority table (18) are used for page management. A page management method featuring: