JPS5919288A - Virtual storage control system - Google Patents

Abstract

PURPOSE:To increase the number of segments possible for one virtual address space and to attain the presence of segments of a large size at the same time in a range of a limited virtual address length, by spliting the virtual address space into segments and pages. CONSTITUTION:The virtual address space consists of two kinds of large and small segments having different segment size, and when the virtual address VA is the 1st kind virtual address corresponding to the address in a small segment, a large segment number LSN designates a large segment, a small segment number SSN designates a small segment, a page number VPN designates the page, and a relative address is designated with an address OFFSET in the page. On the other hand, when the virtual address VA corresponds to the address in the large segment, the large segment number LSN designates the large segment, the link information between the small segment number SSN and the page number VPN designates an objective page and the address OFFSET in the page designates the relative address in the objective page.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention divides a virtual address space into segments and divides the divided space into a real storage device that is managed in units of one frame. The present invention relates to a virtual memory control method suitable for a virtual memory system that dynamically allocates data when necessary.

[Technical background of the invention and its problems]

Generally, in this type of virtual storage system, the virtual address space is divided into segments, which are collections of logically identical information in terms of protection, ownership, sharing, etc. Furthermore, each segment is made up of a collection of targets. A virtual address indicates an address position in such a virtual address space. As shown in Figure 1, a virtual address consists of a segment number SN that specifies a segment, a page number PN1 that specifies a node within the segment, and an intra-page address 0FFSET that specifies a relative address (i.e. displacement) within the segment. ing. The segment number SN is indicated by the upper address of the virtual address, and the number of segments is determined by its bit length. On the other hand, the size of each segment is the page number PN and address 0 in EZ
It is determined by the bit length of the connection information with FFSET (information specifying the intra-segment address).

By the way, in a virtual storage system, it is sometimes advantageous to have a large segment size.

Conventionally, in order to increase the size of a segment in a virtual address space defined by a virtual address with a limited (constant) bit length, the bit length of the information field that specifies the address within the segment has to be increased, that is, the segment number It was necessary to shorten the bit length of the SN field.

In this case, the disadvantage arises that the number of segments that can be accommodated in one virtual address space is reduced. -! However, if the segment size was even small, it had the disadvantage that the virtual address space could not be used effectively.

On the other hand, there are cases in which it is advantageous if one virtual address space can accommodate a large number of segments. To do this, increase the bit length of the segment number SN field.
That is, it was necessary to shorten the bit length of the field of information specifying the intra-segment address. In this case, a disadvantage arises in that the size of all segments becomes small.

Another drawback is that the size of the segment table, which is a cheagle for managing segments, becomes too large.

[Purpose of the invention]

The present invention has been made in view of the above circumstances, and its purpose is to:
To provide a virtual memory control method that can increase the number of segments that one virtual address space can have within a limited virtual address length range and at the same time allow the existence of large-sized segments. be.

[Summary of the invention]

According to the present invention, both large segments with a large segment size and small segments with a small segment size coexist as segments in a virtual address space. Therefore, in the present invention, we propose a virtual address structure consisting of a large segment number field, a small segment number field, a target number field, and an address field in the middle. Specifying an intra-segment address using a concatenated field between a field, a 4-no number field, and a 4-no address field, specifying a small segment using a concatenated field between a large segment number field and a small segment number field, and specifying a page number field and a page. K is provided so that an intra-segment address can be specified by a concatenation field with an intra-segment address field.

To avoid this, the present invention provides a large segment table corresponding to large segment numbers and a small segment table corresponding to small segment numbers. Then, regardless of whether the virtual address indicates one address position within a small segment or one address position within a large segment, the large segment table is referenced by the contents of the large segment number field of the virtual address. I have to. And in the present invention, each en) of the large segment table
IJ indicates whether the corresponding virtual address is a virtual address indicating an address position within a small segment (this is called a type 1 virtual address), or - within a large segment.
In addition to preparing type information indicating whether the address is a virtual address indicating the address location (this is referred to as a type 2 virtual address), it is also supported for entries whose type information indicates that it is a type 1 virtual address. The starting point information of the small segment table is prepared, and the starting point information of the corresponding page table is prepared for the en) IJ indicating that it is a type 2 virtual address.

The above small segment table is referenced by the start point information of the above small segment table and the contents of the small segment number field of the virtual address, and each En) IJ has the start point information of the corresponding target table. has been done. Therefore, in the present invention, in order to convert a virtual address to a real address, the following steps are required: large segment table → small segment table →
The type information specifies the route that needs to go through either the reference route of the note table or the reference route of the large segment table → Peso table.

[Embodiments of the invention]

Hereinafter, one embodiment of the present invention will be described with reference to the drawings. FIG. 2 shows the configuration of a temporary storage system to which the present invention is applied, in which 10.10... is a processor, 20.20...
... are input/output channels (hereinafter referred to as CH).

In this embodiment, these processors 10.10...,
The address handled by CH2O, 20, . . . is a virtual address VA. As shown in FIG. 3, the virtual address VA is composed of a large segment number LSN, a small segment number ssN, a -s-number VPN, and an internal address 0FFSET. In this embodiment, the virtual address space is divided into segments called large segments, and desired segments among these large segments are further divided into segments called small segments. In other words, the virtual address space has two types of segments with different segment sizes (large segment and small segment).
It consists of a collection of trenches. If the virtual address VA is a type 1 virtual address that corresponds to an address within a small segment, the large segment number LSN specifies the large segment, and the small segment number SSN specifies the small segment (within the specified large segment). It is supposed to be done.

That is, as shown in FIG.
The target segment is specified by concatenated information between the SN and the small segment number SSN. Then, the page number VPN is used to specify a page number, and the intra-page address 0FFSET is used to specify a relative address in the page.

On the other hand, when the virtual address VA corresponds to an address within a large segment (a second type virtual address), the large segment number LSN specifies the large segment (target segment) and the small segment number The concatenation information between the SSN and the page number VPN specifies the destination page (within the specified segment). Then, the relative address in the target page is specified by the address 0FFSET in 4-.

30 is a memory device (hereinafter referred to as MEM). M
A large segment table (hereinafter referred to as L) is used for E M and Vθ.
(referred to as ST) 31, small segment table (hereinafter referred to as S
(referred to as ST) s2. a2°... and page tables (hereinafter referred to as PT) 33, 33... are placed. The LST 31 has entries corresponding to large segments (including large segments made up of small segments). The format of these entries differs depending on whether the corresponding large segment is a collection of small segments or a single large segment. In the former case, the entry contents are 5ST, as shown in Figure 6.
It consists of small segment table starting point address information (first type address conversion information) SSTO indicating one starting point address of 32, 32, . . . and segment management information. In addition to protection information for memory access protection, the segment management information includes type information T indicating the type of virtual address VA. Type information T is virtual address VA
If is a type 1 virtual address, T = '0'', and if it is a type 2 virtual address, T -''
1”.

Therefore, the type information T in FIG. 6 is "0".

On the other hand, the entry contents in the latter case are, as shown in FIG. It consists of information. In this case, the type information T included in the segment management information is °l'''.

Referring again to FIG. 2, 40 is a Penning device, 50 is a memory control device connected to MEM, 3o, and 6
0 is Grossetassa 10.10..., CH2O.

20..., a memory control device 50, etc., are connected to each other. The memory control device 50 has the following functions in addition to normal memory control functions. That is, the memory control device 50 is 0.10.
, CH2O, 20, etc. on the 7-stem path 60 is converted into a real address RA and MEM,? It has an address translation function for accessing 0. In the memory control device 50,
Reference numeral 51 denotes a virtual address translation mechanism (hereinafter referred to as VA
), 52 is M E M , ? L S T , which is placed on 0? This is a large segment table starting point address translation mechanism (hereinafter referred to as 5TOR) in which starting point address information of 1 is set. 53 is a real address renoster (hereinafter referred to as RAR) in which the real address RA to be outputted is set in MEMJ (7), and 54 is an address conversion unit.The address conversion unit 54 converts the virtual address VA into the real address RA. It forms the center of the address translation mechanism for converting into . Address translation operation centered on this address translation unit 54 will be explained with reference to FIGS. 8, 9.

FIG. 8 is a functional configuration diagram schematically showing the address translation function of the address translation unit 54 when the virtual address VA is a first type virtual address (indicating one address within a small segment).

The virtual address VA sent out on the system path 60 for memory access to the MEM 30 is VAR,57
The number is placed in . Under the control of the address translation unit 54, the contents of the corresponding entry in the LST 31 are read out based on the contents of the 5TOR 52 and the large segment number LSN in the virtual address VA set in the VAR 5J. Then, it is determined whether the type information T in the segment management information included in the entry is 0'' or 1''. When T=“0” as shown in FIG. 8, the address conversion unit 54 determines that the virtual address VA is a type 1 virtual address, and the type 1 address conversion information ( In this example of T="O", the small segment table starting point address information 5STO
) in 5ST32 specified by
Refer to the en) l) corresponding to the small segment number SSN in the virtual address VA.

Then, the address translation unit 54 performs an access protection check based on the segment management information in the entry, and also converts the virtual address VA in P T 33 specified by the 4-note table starting point address information PTO included in the entry. Refer to the entry corresponding to the 4-so number VPN. In the above corresponding entry of PrB6, the frame number PFN of the target target node is written, and the connection information between PF'N and the frame address OF"FSET in the virtual address VA. is placed in the RAR 53 as the real address RA. This is the address conversion when the virtual address VA is a type 1 virtual address. Therefore, the virtual address VA in this case is a combination of its large segment number LSN and small segment. The target segment (small segment) is specified by the number SSN, and the page number VPN and the 4-internal address 0FFSET are interpreted as indicating the segment address (this is called small segment interpretation).

FIG. 9 schematically shows the address translation function by the address translation unit 54 when the virtual address VA is a type 2 virtual address (indicating an address within a large segment that does not include any small segments, that is, one address within a single large segment). It is a functional configuration diagram. Contents and VA of ST On 52
Based on the large segment number LSH in the virtual address VA placed in R57, LST, ? The contents of the corresponding entry of 7 are read and whether T is 0' or °゛1
The determination as to whether # is made is the same as in the case described above. When T=“1” as shown in FIG. 9, the address translation unit 54 determines that the virtual address VA is a type 2 virtual address, and performs an access protection check based on the segment management information included in the entry. Do the following.

The address translation unit 54 also converts the first type address translation information (i in this example where T=“1”) included in the entry
t, -s- table starting point address information PTO) in PrB6, the small segment number SSN in the virtual address VA and the small segment number VPN
Refer to the entry corresponding to the connection information. PrB6
As mentioned above, the 4-frame number PFN of the target page is written in the corresponding entry above, and the PFN of and the target internal address 0F in the virtual address VA.
Connection information with FSET is RAR5 as real address RA
，? The number is placed in .

This is address translation when the virtual address vA is the second type virtual address. Therefore, the virtual address VA in this case is its large segment number LSN
The target segment (large segment) is specified with , and the small segment number SSN, target number VPN, and in-page address FF5ET are interpreted as indicating the segment address (this is called large segment interpretation). become.

In this way, according to this embodiment, the virtual address space is not equally divided into segments of the same size as in the past, but an arbitrary number of large-sized segments (large segments) and an arbitrary number of small-sized segments ( In this case, two interpretations, large segment interpretation and small segment interpretation, can coexist. Therefore, according to this embodiment, it is possible to simultaneously increase the number of segments per virtual address space (by small segment interpretation) and to allow the existence of segments with large segment sizes (by large segment interpretation). . For this reason, compared to the conventional method of simply lengthening the segment number SN (see Figure 1) to increase the number of segments that a virtual address space can have, the number of small-sized segments is larger than necessary. The segment table (LST31,5
ST32°32...) does not need to increase in size.

Note that in the above embodiment, the table is referenced one more time than in the conventional method when interpreting a small segment, so there is a risk that the address translation time will be longer; however, an address translation buffer (also called an associative register) is provided. , if the system adopts a method that performs address translation using a conversion pair in the address conversion/gusso when there is a hit,
” - Fears such as those mentioned above will be eliminated.

Incidentally, the size and number of required large segments and small segments are determined by the task. Therefore, L S T ,? It is convenient to prepare the first prize for each task. Incidentally, in the embodiment described above, a case has been described in which the central part of the address translation mechanism is provided in the memory control device 50, but according to the essence of the present invention, the processor 1θ.

10..., CH2θ, 20... may be provided separately. In this case, processor 10.1
0..., CH2O, 20... to system gas 6
The address sent on 0 becomes the real address.

〔Effect of the invention〕

As detailed above, according to the virtual memory control method of the present invention, it is possible to increase the number of segments that one virtual address space can have within a limited virtual address length range, and at the same time, it is possible to increase the number of segments that one virtual address space can have within a limited virtual address length range. Existence can also be made possible.

[Brief explanation of drawings]

Figure 1 is a diagram showing the format of a conventional virtual address.
FIG. 2 is a block diagram showing an embodiment of the virtual storage system to which the present invention is applied, FIG. 3 is a diagram showing the format of the virtual address applied in the above embodiment, and FIGS. 4 and 5 are the above 6 and 7 are functional configuration diagrams schematically showing address translation functions in segment interpretation in large segment tables. 31...Large segment table (LST), 32°3
2...Small segment table, 33.33...Page table, 54...Address translation section. Applicant's agent Patent attorney Takehiko Suzue Figure 8 Figure 91A

Claims (1)

[Scope of Claims] A large segment table having type information indicating the type of virtual address and type 1 address conversion information in each segment table entry, and a small segment table having type 2 address conversion information in each segment table entry. , a beno table having type 3 address translation information in each Zeno table entry, and a virtual address having a large segment number field, a small segment number field, a Zeno number field, and an internal address field. Using the contents of the thick segment number field, refer to the corresponding segment table entry (IJ) in the large segment table and determine whether the corresponding virtual address is a type 1 virtual address or a type 2 virtual address based on the type information in the entry. means for determining whether the virtual address is a virtual address of the first type; and if the virtual address is the first virtual address, the first type at in the segment table I-IJ; a corresponding segment table entry) of said small segment Cheagle based on the address translation information and the contents of the small segment number field in said virtual address; Based on the type address conversion information and the contents of the 4-No. number field in the above virtual address, refer to the corresponding Baso table entry in the 1-no table and convert the 1-hi No. 3 type address translation in the entry. means for obtaining a real address based on the information and the contents of the address field in the table in the virtual address, and when the virtual address is the second type virtual address, a corresponding segment entry in the large segment table) IJ Based on the first type address conversion information in the virtual address and the concatenation information between the contents of the small segment number field and the contents of the 4-number field in the virtual address, the corresponding page table of the 1-no table is created.
a means for obtaining a real address from the third type address conversion information in the IJ and the contents of the in-page address field in the virtual address. control method.