Processor-bus-connected flash storage paging device using a virtual memory mapping table and page faults

• US 8,627,040 B2
• Filed: 12/31/2012
• Issued: 01/07/2014
• Est. Priority Date: 10/01/2009
• Status: Active Grant

• Current Assignee: Oracle America, Inc. (Oracle Corporation)
• Original Assignee: Oracle America, Inc. (Oracle Corporation)
• Inventors: Koka, Pranay, McCracken, Michael Oliver, Schwetman, Herbert Dewitt Jr., Bonebakker, Jan Lodewijk
• Primary Examiner(s): Kim, Hong
• Application Number:
  US13/731,760
• Publication Number:
  US 20130145086A1
• Time in Patent Office: 372 Days
• Field of Search: 711/103, 711/118, 711/154, 711/203, 710/22, 709/217
• US Class Current: 711/203
• CPC Class Codes: G06F 12/0246 in block erasable memory, e.g. flash memory
• CPC Class Codes: G06F 12/08 in hierarchically structured memory systems, e.g. virtual memory systems
• CPC Class Codes: G06F 12/0802 Addressing of a memory level in which the access to the desired data or data block requires associative addressing means, e.g. caches
• CPC Class Codes: G06F 12/0866 for peripheral storage systems, e.g. disk cache
• CPC Class Codes: G06F 12/10 Address translation
• CPC Class Codes: G06F 13/28 using burst mode transfer, e.g. direct memory access DMA, cycle steal G06F13/32 takes precedence
• CPC Class Codes: G06F 2212/2022 Flash memory
• CPC Class Codes: G06F 2212/214 Solid state disk

Abstract

A method for accessing a virtual memory of a processor using a processor-bus-connected flash storage module (PFSM) as a first paging device and a hard disk drive (HDD) as a second paging device, the method including: allocating a first address partition and a second address partition of a virtual memory for a software application of a processor to the first paging device and the second paging device, respectively, identifying a virtual memory page in the first paging device responsive to a page fault of the virtual memory triggered by the software application, sending a page access request to the PFSM for accessing the virtual memory page responsive to the page fault, and receiving the virtual memory page from the PFSM based on a command of the processor bus issued by the PFSM in conjunction with performing a flash memory access in the flash memory using a flash page address.

Claims

1. A method for accessing a virtual memory of a processor using a processor-bus-connected flash storage module (PFSM) as a first paging device and a hard disk drive (HDD) as a second paging device, the PFSM operatively coupled to the processor via a processor bus, the PFSM comprising a flash memory and a virtual address mapping table, the method comprising:

allocating a first address partition and a second address partition of the virtual memory for a software application of the processor to the first paging device and the second paging device, respectively;

identifying a virtual memory page in the first paging device responsive to a page fault of the virtual memory triggered by the software application;

sending a page access request to the PFSM for accessing the virtual memory page responsive to the page fault, wherein the page access request is sent via the processor bus and comprises a virtual address of the virtual memory page; and

receiving the virtual memory page from the PFSM based on a command of the processor bus issued by the PFSM in conjunction with performing a flash memory access in the flash memory using a flash page address, wherein the virtual address mapping table translates the virtual address of the virtual memory page to the flash page address in the flash memory.

2. The method of claim 1, wherein defining the first address partition and the second address partition of the virtual memory is based on a memory access pattern of the software application.

3. The method of claim 1, further comprising:

defining the first address partition and the second address partition of the virtual memory when an operating system of the processor is starting up.

4. The method of claim 1, further comprising:

defining the first address partition and the second address partition of the virtual memory when the software application of the processor is starting up.

5. The method of claim 1, further comprising:

defining the first address partition and the second address partition of the virtual memory when the software application of the processor requests memory from an operating system of the processor.

6. The method of claim 1, wherein the PFSM further comprises a buffer memory and a processor accessible command register mapped into an address space of the processor, the method further comprising:

storing, by the PFSM, one or more parameters of the page access request in the buffer memory as a context of the page access request, wherein the one or more parameters are received by the PFSM using the processor accessible command register; and

scheduling, by the PFSM, a direct memory access (DMA) operation responsive to receiving a trigger parameter of the one or more parameters,

wherein the DMA operation comprises performing the flash memory access and the command of the processor bus.

7. The method of claim 6, further comprising:

generating, by the PSFM, an interrupt to the processor when the DMA operation is completed.

8. The method of claim 6, wherein the flash memory and a cache partition of the buffer memory forms a memory hierarchy of the PFSM, the method further comprising:

performing a cache operation by the PFSM according to a cache policy of the memory hierarchy responsive to receiving the trigger parameter, wherein the flash memory access is scheduled as a result of the cache operation.

9. The method of claim 6, further comprising:

identifying a cached flash page address in the cache partition for the virtual address based on the virtual address mapping table,

wherein the cache operation is based on the cached flash page address in the cache partition.