Systems and methods for I/O processing using out-of-band hinting to block driver or storage controller

• US 9,378,152 B2
• Filed: 05/09/2014
• Issued: 06/28/2016
• Est. Priority Date: 05/09/2014
• Status: Active Grant

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: Avago Technologies General IP PTE Limited (Broadcom, Inc.)
• Inventors: Sampathkumar, Kishore Kaniyar, Maharana, Parag, Samanta, Sumanesh, Purkayastha, Saugata Das
• Primary Examiner(s): KIM, HONG CHONG
• Application Number:
  US14/274,153
• Publication Number:
  US 20150324300A1
• Time in Patent Office: 781 Days
• Field of Search: 711/137, 711/138, 711/139, 707/822
• US Class Current: 1/1
• CPC Class Codes: G06F 12/0871 Allocation or management of cache space
• CPC Class Codes: G06F 12/0888 using selective caching, e.g. bypass
• CPC Class Codes: G06F 12/122 of the least frequently used [LFU] type, e.g. with individual count value
• CPC Class Codes: G06F 12/123 with age lists, e.g. queue, most recently used [MRU] list or least recently used [LRU] list
• CPC Class Codes: G06F 2212/1016 Performance improvement
• CPC Class Codes: G06F 2212/222 Non-volatile memory
• CPC Class Codes: G06F 2212/604 Details relating to cache allocation
• CPC Class Codes: G06F 2212/6046 Using a specific cache allocation policy other than replacement policy

Abstract

A storage subsystem can achieve more efficient I/O processing by enabling users to specify and pass out of band I/O hints comprising an object to be hinted, a hint type, and caching strategies associated with a hint type. A hinted object may be either a virtual device or a file. In addition to priority cache, hint types may include never-cache, sticky-cache, and volatile-cache. Hints may be passed via command-line or graphical-user interfaces.

Claims

1. A method for processing at least one Input/Output (I/O) request issued by an application to at least one of a filename, a device, and a continuous range of logical block addresses (LBA) of a virtual device via out-of-band hinting, comprising:

directly interfacing with at least one of a storage controller and a block driver while bypassing an I/O stream;

defining at least one hint, the at least one hint including the at least one of a filename, a device, and a continuous range of logical block addresses,

a hint type, and

associated instructions for processing the at least one I/O request; and

passing the at least one hint to the at least one of a storage controller and a block driver while bypassing the I/O stream.

2. The method of claim 1, wherein the hint type includes at least one of a priority-cache hint type, a never-cache hint type, a sticky-cache hint type, and a volatile-cache hint type.

3. The method of claim 2, wherein the hint type is a priority-cache hint type and the associated instructions include

instructions for maintaining at least one virtual cache window associated with the at least one I/O request in a first queue associated with a priority value.

4. The method of claim 3, wherein the first queue is a least-recently-used queue and the priority value is selected from a continuous range of integers from 1 to 15.

5. The method of claim 2, wherein the hint type is a never-cache hint type and the associated instructions include

instructions for passing the at least one I/O request directly to a storage device;

instructions for preventing the creation of a physical cache window associated with at least one continuous range of logical block addresses associated with the at least one I/O request; and

instructions for forcing eviction of the at least one continuous range of logical block addresses.

6. The method of claim 2, wherein the hint type is a sticky-cache hint type and the associated instructions include

instructions for converting at least one continuous range of logical block addresses associated with the at least one I/O request to a physical cache window;

and

instructions for maintaining at least one continuous range of logical block addresses associated with the at least one I/O request in a second queue, if the at least one continuous range of logical block addresses has been modified and its contents written to a storage device.

7. The method of claim 2, wherein the hint type is a volatile-cache hint type and the associated instructions include

instructions for converting at least one continuous range of logical block addresses associated with the at least one I/O request to a physical cache window;

and

instructions for maintaining the at least one continuous range of logical block addresses in a third queue if the size of an associated virtual device is not greater than the size of the associated cache device.

8. The method of claim 2, wherein the hint type is at least one of a sticky-cache classification and a volatile-cache hint type and the associated instructions include

instructions for flagging the at least one continuous range of logical block addresses associated with the at least one I/O request as either sticky-cache or volatile-cache;

and

instructions for maintaining the at least one continuous range of logical block addresses in a second queue.

9. The method of claim 1, wherein the passing the at least one hint to the at least one of a storage controller and a block driver includes

passing the at least one hint to the at least one of a storage controller and a block device driver via at least one of a command-line interface and a graphical user interface.

10. The method of claim 1, wherein the specifying at least one hint includes

determining the file system to which the at least one file belongs;

determining an index node uniquely associated with the at least one file;

searching at least one hint table for a hint associated with the index node; and

returning at least one of an associated hint type and a null value.

11. The method of claim 1, wherein the passing the at least one hint to a block driver includes:

notifying the at least one block driver of a change in hint type.

12. The method of claim 1, wherein the defining at least one hint, the at least one hint including the at least one of a filename, a device, and a continuous range of logical block addresses, a hint type, and associated instructions for processing the at least one I/O request, includes:

defining instructions associated with transitioning the at least one of a filename, a device, and a continuous range of logical block addresses from a first hint type to a second hint type.

13. A system for managing a processing of an Input/Output (I/O) request from at least one application via out-of-band hinting, comprising:

a hint engine configured to enable the at least one application to specify at least one hint and to pass the at least one hint to at least one of a block driver and a storage controller;

a storage controller including hint firmware configured to directly process the at least one hint;

a block driver including a hint driver configured to directly process the at least one hint and to notify the hint firmware of a change in hint type;

a configuration tool communicatively coupled to the hint driver and to the hint firmware, configured to manage the at least one hint;

at least one virtual device including a first continuous range of logical block addresses (LBA);

at least one file system operably coupled to the block driver; and

at least one storage device operably coupled to the storage controller.

14. The system of claim 13, wherein the at least one storage device includes

at least one cache device including a plurality of cache windows, each cache window including a continuous range of logical block addresses, a metadata structure, and a plurality of cache lines.

15. The system of claim 13, wherein the at least one hint includes

at least one of a filename, a device, and a second continuous range of LBAs of the virtual device;

and

a hint type.

16. The system of claim 15, wherein the at least one hint further includes:

a flag indicating whether the at least one hint is a file hint or a device hint.

17. The system of claim 13, wherein the configuration tool is configured to

load the at least one hint;

query the at least one hint;

modify the at least one hint;

remove the at least one hint; and

pass the at least one hint via at least one of a graphical user interface and a command-line interface.

18. The system of claim 13, wherein at least one of the hint driver and the hint firmware is further configured to process additional instructions associated with the change in hint type.

19. The system of claim 13, wherein the hint driver includes

at least one hint table, the at least one hint table including at least one hint device, each hint device associated with at least one file system, at least one unique identifier corresponding to the at least one file system, each file system associated with at least one index node, each index node uniquely associated with a filename.

20. A data storage apparatus configured to manage a processing of an Input/Output (I/O) request from at least one application via out-of-band hinting, comprising:

a hint engine configured to enable the at least one application to specify at least one hint and to pass the at least one hint to at least one of a block driver and a storage controller;

a storage controller including hint firmware configured to directly process the at least one hint;

a block driver including a hint driver configured to directly process the at least one hint and to notify the hint firmware of a change in hint type;

a configuration tool communicatively coupled to the hint driver and to the hint firmware, configured to manage the at least one hint;

at least one virtual device including a first continuous range of logical block addresses (LBA);

at least one file system operably coupled to the block driver; and

at least one storage device operably coupled to the storage controller.