JP3061001B2 - Memory allocation method in computer system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a computer system, and more particularly, to a memory allocation method used in a computer system.

[0002]

2. Description of the Related Art Generally, in a computer system, an operating system is provided with a mechanism (function) for managing a memory in page units and allocating the memory in response to a request. On the other hand, when the operating system operates, the page that is zero-cleared is often required. Thus, when the page that is zero-cleared is required, the operating system performs zero-clearing when allocating the page. .

When the entire page is cleared to zero, it is necessary to write data over a relatively wide range. For this reason, it takes time to perform the process itself when the entire page is cleared to zero.

[0004] In addition, when the entire page is cleared to zero, a large number of cache replacements of the processor occur. For this reason, the data that has been cached before the page clearing process is replaced, and reloading from the memory to the cache may occur in a later process, thereby deteriorating the performance of the computer.

[0005]

As described above, in the conventional computer system, the page clearing process takes a long time because the page clearing process is performed when a zero-cleared page is required. There is.

Further, according to the present invention, when allocating a zero-cleared page, a page requiring a large amount of writing to the memory is cleared. When the subsequent processing is continued, there is a problem that re-reading from the memory is required and computer performance is reduced.

An object of the present invention is to provide a memory allocation method capable of reducing the time required for allocating when a zero-cleared memory page is required in a computer system.

[0008]

According to the present invention, in a computer system which manages a plurality of memory areas and allocates them in response to a request , a memory area in a free state is allocated to a memory area in a free state.
First pooling means for pooling and zero-cleared notes
Second pool means for pooling the storage area;
From the control means to the free state scheduled for allocation.
Fetch the memory area, and zero out the contents of the memory area.
Clearing machine that moves to the second pool means
And whether the load on the computer system is low or not.
If the load on the computer system is low upon detection,
First processing means having a load monitoring mechanism for activating the mechanism
When the allocate request is received, the zero is cleared.
When it is determined that a memory area is needed, the second
Allocate the zero-cleared memory area from the pool
And the zero-cleared page is requested
If it is determined that there is no free pool from the first pool means
And a second processing means for allocating a memory area in a state .

[0009]

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings.

Referring to FIG. 1, in a computer system (not shown), an operating system manages a memory in page units. The computer system is provided with a load monitoring mechanism (system load monitoring mechanism) 1, and the system load monitoring mechanism 1 monitors the load status of the computer system. Then, the system load monitoring mechanism 1 determines whether the current system load is high or low.

When the system load monitoring mechanism 1 determines that the system load is low, the page zero clearing mechanism 2 is activated. The page zero clearing mechanism 2 extracts a page in a free state which is to be allocated when the next page is requested from the free page pool 3, and clears its contents to zero. Then, this page is moved to the zero-cleared page pool 4.

When the page requester 6 needs a zero-cleared page, the page requester 6 requests the zero-cleared page from a page allocator (page allocator) 5. When determining that the zero-cleared page is needed, the page allocating mechanism 5 takes out the page from the pool of cleared pages prepared by the page zero clearing mechanism 5 and returns it to the requester 6. On the other hand, when the zero-cleared page is not requested, the page allocating mechanism 5 returns a page in a free state from the free page pool 3.

Here, a UNIX operating system will be described as a specific example.

In the UNIX operating system,
When there are no more runnable processes, a transition is made to a state called idle. This idle state means that the system load is low, and the transition to this state triggers the load monitoring mechanism 1 to reset the page zero clear mechanism 2
Start

The page zero clear mechanism 2 takes out a page from the free page pool 3 and clears the contents to zero. The cleared page is added to a dedicated pool (cleared free page pool) 4.

The above processing is continued until a runnable process appears.

When an application program (requester) requests a BSS (zero-cleared data area), the operating system (OS) allocates a page that has been cleared to zero to the application program. At this time, a page that has been cleared to zero is requested to the page allocation mechanism 5.

The page allocating mechanism 5 takes out the page whose contents have been zero-cleared by the page zero clearing mechanism 2 from the cleared free pool 4 and returns it to the requester 6. if,
If the cleared pool is empty, free page pool 3
The page in the free state is taken out from, the content is cleared to zero, and returned to the requester 6.

The above-mentioned memory (page) allocation can be applied to a system in which it is expected that a memory having a specific content is required. In this case, the page zero clear mechanism 2 shown in FIG. 1 is replaced with a mechanism for writing specific contents. This writing mechanism can speed up the process of allocating a memory of a specific content.

[0021]

As described above, according to the present invention, the zero clear processing of a page is performed only when the load on the system is low, and the zero clear processing of the page is not performed at the time of page allocation. Page clearing process at the time of page allocation like this,
This has the effect of speeding up the actual page allocation process.

Further, according to the present invention, the page zero-clear processing is performed only when the system load is low, and the page zero-clear processing is not performed at the time of page allocation. This has the effect of speeding up the page allocation process and subsequent processes.

[Brief description of the drawings]

FIG. 1 is a block diagram for explaining a memory allocation method according to the present invention.

[Explanation of symbols]

 1 load monitoring mechanism (system load monitoring mechanism) 2 page zero clear mechanism 3 free page pool 4 zero cleared page pool 5 page allocate mechanism (page allocator) 6 page requester

──────────────────────────────────────────────────続 き Continued on the front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) G06F 1 / 24,9 / 46 G06F 12/00-12/06 G06F 12/16

Claims (2)

(57) [Claims] 1. A first pool for pooling a memory area in a free state in a computer system that manages a plurality of memory areas and performs allocation in response to a request.
Means and a second pool for pooling zero-cleared memory areas
Means from said first pool means and said file to be allocated.
Fetches the memory area in the
Clear the contents to zero and transfer to the second pool means
And the load on the computer system is low.
If it is detected whether the load of the computer system is low
A first having a load monitoring mechanism for activating the clearing mechanism;
Processing means and, upon receiving an allocate request,
When it is determined that the storage area is needed, the second pool
Allocating the zero-cleared memory area from
And the zero-cleared page is not requested
And the free state is returned from the first pool means.
And a second processing means for allocating the memory area of (1) . 2. A computer system for managing a plurality of memory areas and allocating a memory area having a predetermined content according to a request, wherein the computer system detects whether a load on the computer system is low and detects whether the load on the computer system is low. If the system load is low, the specific memory area is rewritten to the specified content ,
For subsequent allocation requests, the content specified above
Determined that a rewritten memory area is needed
Then, the rewritten memory area is allocated,
A page rewritten to the specified content is requested
If it is determined that there is no
A memory allocation method in a computer system, comprising a means for allocating.