JP2008158773A - Information processing apparatus and memory management method - Google Patents

Abstract

In an information processing apparatus having a suspend / resume function, it is possible to further reduce the time required for resuming.
When suspending, memory management utility 101 saves in-use data existing in volatile memory 13 in nonvolatile memory 12 so that the area of volatile memory 13 becomes one of the virtual address space. If it is a part of the virtual address space, the page table entry is stored in the save destination non-volatile memory so that the restoration from the non-volatile memory 12 to the volatile memory 13 at the time of resume is omitted. The history of the copy (copy from the volatile memory 13 to the non-volatile memory 12) to the copy management table 150 used for restoring the data to the volatile memory 13 is updated while indicating the area of the volatile memory 12 The recording of is omitted.
[Selection] Figure 1

Description

  The present invention relates to a memory management technique suitable for being applied to a personal computer having a so-called suspend / resume function.

  In recent years, various types of personal computers such as a notebook type and a desktop type are widely used. This type of personal computer generally has a so-called suspend / resume function that makes it possible to resume work from a state where it was interrupted at the time of leaving the day before, for example.

This suspend / resume function saves the operating state at the time when a suspend instruction is received, for example, by pressing the power button, and restores the saved operating state when a resume instruction is received. To achieve. Most of the processing is spent on copying in-use data on volatile memory onto non-volatile memory and re-copying the copied data onto non-volatile memory into volatile memory. ing. For this reason, various ideas have been proposed so far in order to shorten the time required for suspending and resuming to quickly complete the copying of data in use (see, for example, Patent Document 1).
International Publication No. 01/037066 Pamphlet

  The information processing apparatus disclosed in Patent Document 1 shortens the time required for suspending and resuming by using a flash memory or the like that has a higher operating speed than the HDD or the like as a save destination of in-use data existing in a DRAM or the like. Is.

  By the way, in this method, all data saved in the flash memory or the like is uniformly written back to the DRAM or the like at the time of resume. However, recently, since the installed memory has a tendency to increase in capacity, further contrivances for reducing the time required for suspending and resuming have begun to be required.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide an information processing apparatus and a memory management method that can further reduce the time required for resuming.

  In order to achieve the above-described object, the information processing apparatus of the present invention designates a volatile memory that can be accessed by designating a physical location on the data storage area, and designates a physical location on the data storage area. Accessible nonvolatile memory, and a evacuation means for evacuating data in use stored in the volatile memory to the nonvolatile memory when the power is turned off while maintaining the operation state at that time, and the evacuation means Updating means for re-mapping the data storage area in the non-volatile memory as the save destination to the area in the main memory space to which the data storage area in the volatile memory in which the data is saved is mapped It is characterized by.

  According to the present invention, it is possible to provide an information processing apparatus and a memory management method that can further reduce the time required for resuming.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 shows a schematic configuration of an information processing apparatus according to an embodiment of the present invention. The information processing apparatus 10 is realized as, for example, a notebook type or desktop type personal computer.

  As shown in FIG. 1, the information processing apparatus 10 includes a CPU 11, a nonvolatile memory 12, a volatile memory 13, and an HDD / flash ROM 14.

  The CPU 11 is a processor that controls the operation of each unit in the information processing apparatus. The CPU 11 executes an operating system (OS) 100 loaded from the HDD 14 / flash ROM 14 to the nonvolatile memory 12 or the volatile memory 13 and various programs operating under the OS 100. Among these various programs, there is a memory management utility 101 described later.

  The non-volatile memory 12 is a memory device that is configured by, for example, MRAM, FeRAM, DRAM backed up by self-refresh, etc., and can retain data permanently, while the volatile memory 13 is DRAM or the like. A memory device configured to hold data temporarily (while power is supplied). Both the nonvolatile memory 12 and the volatile memory 13 are memory devices that can be accessed linearly, that is, can be accessed by designating a physical position on the data storage area.

  The HDD / flash ROM 14 is a hybrid storage device having both a hard disk and a flash ROM, and stores a large amount of various programs and various data as auxiliary devices for the nonvolatile memory 12 and the volatile memory 13.

  The information processing apparatus 10 having such a configuration has a so-called suspend / resume function that makes it possible to resume work from the state at the time of interruption. The above-described memory management utility 101 executes and controls saving / restoring of in-use data stored in the volatile memory 13 with respect to the suspend / resume function. More specifically, the memory management utility 101 basically saves in-use data stored in the volatile memory 13 to the nonvolatile memory 12 during suspension, and uses the amount exceeding the free capacity of the nonvolatile memory 12. If medium data exists in the volatile memory 13, the excess is saved in the HDD / flash ROM 14. Then, the memory management utility 101 restores the in-use data saved in the nonvolatile memory 12 and the HDD / flash ROM 14 to the volatile memory 13 at the time of resume. For this restoration, the memory management utility 101 manages on the nonvolatile memory 12 a copy management table 150 that records the correspondence between the save source data storage area and the save destination data storage area.

  Incidentally, as described above, both the nonvolatile memory 12 and the volatile memory 13 are linearly accessible memory devices. Therefore, these data storage areas can be allocated to a main memory space (virtual address space) accessible by the CPU 11. Focusing on this point, the information processing apparatus 10 is provided with a mechanism for reducing the time required for data restoration at the time of resume. Hereinafter, this point will be described in detail.

  FIG. 2 shows the allocation status of the virtual address space of the information processing apparatus 10 at the time of suspension. All accesses by the CPU 11 are performed with respect to the virtual address space 21, and the virtual address space 21 and the non-volatile memory 12 and the volatile memory 13 that are physical memories are associated with each other by a page table entry 22. .

  When suspended, the memory management utility 101 saves the data in use stored in the volatile memory 13 to the nonvolatile memory 12 or the HDD / flash ROM 14 and records the history in the copy management table 150. On the other hand, at the time of resume, the memory management utility 101 restores the in-use data saved in the nonvolatile memory 12 or the HDD / flash ROM 14 to the volatile memory 13 based on the copy management table 150. Recently, since the installed memory tends to increase in capacity, it takes time to restore data during use. Therefore, in order to reduce the amount of processing for the restoration, the memory management utility 101 stores in-use data on the data storage area of the volatile memory 13 allocated to the virtual address space 21 by the page table entry 22 in a nonvolatile manner. When saved in the data storage area of the memory 12, the contents of the page table entry 22 are updated. FIG. 3 is a diagram showing the allocation status of the virtual address space of the information processing apparatus 10 after the data in use stored in the volatile memory 13 is saved and the page table entry 22 is updated.

  As shown in FIG. 3, the page table entry 22 in which the address of the data storage area on the volatile memory 13 where the data in use was once stored is stored in the data storage on the non-volatile memory 12 at the save destination. The address of the area is held. For this reason, the CPU 11 can access the data in use without any problem. Compared with the time required to copy the data in use from the nonvolatile memory 12 to the volatile memory 13, the time required to update the page table entry 22 is sufficiently small, so the time required for data restoration at the time of resume is greatly reduced. Realize that. Since the page table entry 22 is managed by the OS 100, the memory management utility 101 requests the OS 100 to update it.

  FIG. 4 is a flowchart illustrating a memory management procedure executed by the information processing apparatus 10 during suspension.

  When suspending, the memory management utility 101 sequentially checks whether there is data (area) in use in the volatile memory 13 (step A1), and if there is an area in use (YES in step A1). Subsequently, it is checked whether an unused area for saving data in the area remains in the nonvolatile memory 12 (step A2).

  If there is an unused area in the nonvolatile memory 12 (YES in step A2), the memory management utility 101 copies the contents of the volatile memory 13 to the nonvolatile memory 12 (step A3). At this time, the memory management utility 101 checks whether the area of the volatile memory 13 is a part of the virtual address space 21 (step A4). In step A4, the page table entry 22 is updated (step A5). If the area of the volatile memory 13 is not a part of the virtual address space 21 (NO in step A4), the memory management utility 101 copies the history of copying from the volatile memory 13 to the nonvolatile memory 12. Record in the management table 150 (step A7).

  On the other hand, if there is no unused area in the non-volatile memory 12 (NO in step A2), the memory management utility 101 copies the contents of the volatile memory 13 to the HDD / flash ROM 14 (step A6). / The history of copying from the flash ROM 14 to the nonvolatile memory 12 is recorded in the copy management table 150 (step A7).

  When the copying to the nonvolatile memory 12 or the HDD / flash ROM 14 is completed, the memory management utility 101 changes the area of the volatile memory 13 to an unused area (step A8) and repeats the processing from step A1. In other words, the memory management utility 101 repeats the above processing until there is no area in use in the volatile memory 13 (NO in step A1).

  In the subsequent resume, conversely, based on the copy management table 150, the memory management utility 101 performs copying from the nonvolatile memory 12 or HDD / flash ROM 14 to the volatile memory 13. Since the copy history from the volatile memory 13 to the non-volatile memory 12 performed for a part of the area is not recorded in the copy management table 150, the corresponding copy is omitted.

  Thus, according to the information processing apparatus 10 of the present embodiment, it is possible to further reduce the time required for the resume.

  In the above, the example in which the update of the page table entry 22 is performed at the time of suspension has been described, but the execution timing can be moved at the time of resume. In this case, when copying to the volatile memory 13 based on the copy management table 150, whether or not an area that is a part of the virtual address space 21 has been copied from the volatile memory 13 to the nonvolatile memory 12 If so, the page table entry 22 may be updated instead of copying the actual data. Alternatively, before copying to the volatile memory 13, the copy management table 150 detects a copy from the volatile memory 13 to the non-volatile memory 12 performed for an area that is a part of the virtual address space 21. It is also possible to update the page table entry 22 and delete the history from the copy management table 150 as a preprocess.

  As described above, the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. In addition, various inventions can be formed by appropriately combining a plurality of components disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, you may combine a component suitably in different embodiment.

The figure which shows schematic structure of the information processing apparatus which concerns on embodiment of this invention The figure which shows the allocation status of the virtual address space before memory management utility operation | movement at the time of suspension of the information processing apparatus of the embodiment The figure which shows the allocation state of the virtual address space after memory management utility operation | movement at the time of suspension of the information processing apparatus of the embodiment 8 is a flowchart showing a memory management procedure executed by the information processing apparatus according to the embodiment during suspension.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Information processing apparatus, 11 ... CPU, 12 ... Non-volatile memory, 13 ... Volatile memory, 14 ... HDD / flash ROM, 21 ... Virtual address space, 22 ... Page table entry, 100 ... Operating system (OS), 101 ... Memory management utility, 150 ... Copy management table.

Claims (8)

Volatile memory accessible by specifying a physical location on the data storage area;
Non-volatile memory that can be accessed by specifying a physical location on the data storage area;
A evacuation means for evacuating data in use stored in the volatile memory to the nonvolatile memory at the time of suspending the power off while maintaining the operation state at that time;
Updating means for re-mapping the data storage area in the non-volatile memory as the save destination to the area on the main memory space to which the data storage area in the volatile memory to which the save means has saved the data is mapped;
An information processing apparatus comprising: When data is saved by the saving unit, for data other than data related to remapping by the updating unit, a data storage area in the save source volatile memory and a data storage area in the save destination nonvolatile memory Recording means for recording the correspondence of
A restoring means for writing back the data saved in the nonvolatile memory to the volatile memory based on the correspondence recorded in the recording means at the time of resuming the power supply while restoring the operation state held at the time of suspension;
The information processing apparatus according to claim 1, further comprising:   The information processing apparatus according to claim 1, wherein the updating unit performs the remapping after the data is saved by the saving unit during the suspend.   The information processing apparatus according to claim 1, wherein the updating unit performs the remapping at the time of the resume and before data restoration by the restoration unit. A non-volatile storage device having a larger storage capacity than the non-volatile memory;
If the amount of data on the volatile memory to be saved exceeds the free capacity on the nonvolatile memory, the saving means saves the excess to the nonvolatile storage device,
The recording means further records the correspondence between the data storage area in the save-source volatile memory and the data storage area in the save-destination nonvolatile storage device;
The restoration means writes the data saved in the nonvolatile storage device back to the volatile memory based on the correspondence recorded in the recording means.
The information processing apparatus according to claim 2. A memory management method for an information processing apparatus comprising a volatile memory and a nonvolatile memory accessible by designating a physical location on a data storage area,
At the time of suspend to turn off the power while maintaining the operating state at that time, the data in use stored in the volatile memory is saved in the nonvolatile memory,
Remap the data storage area in the non-volatile memory that is the save destination to the area on the main memory space to which the data storage area in the volatile memory that has saved the data is mapped.
And a memory management method. When the data is saved, a record that records the correspondence between the data storage area in the save source volatile memory and the data storage area in the save destination nonvolatile memory for data other than the data related to the remapping. ,
Based on the recorded correspondence, the data saved in the non-volatile memory is written back to the volatile memory at the time of resuming the power while restoring the operation state held at the time of suspend.
The memory management method according to claim 6. The information processing apparatus further includes a nonvolatile storage device having a larger storage capacity than the nonvolatile memory,
When the amount of data on the volatile memory to be saved exceeds the free capacity on the nonvolatile memory, the excess is saved to the nonvolatile storage device,
Further recording the correspondence between the data storage area in the save source volatile memory and the data storage area in the save destination nonvolatile storage device;
Based on the recorded correspondence, the data saved in the nonvolatile storage device is written back to the volatile memory.
8. The memory management method according to claim 7, wherein:

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