System and method for user space operations for direct I/O between an application instance and an I/O adapter

• US 20060288125A1
• Filed: 05/23/2005
• Published: 12/21/2006
• Est. Priority Date: 05/23/2005
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Recio, Renato John, Vega, Madeline, Boyd, William Todd, Mena, Agustin III, Hufferd, John Lewis
• Granted Patent: US 7,552,240 B2
• Time in Patent Office: Days
• US Class Current: 710/1
• CPC Class Codes: G06F 9/5011 the resources being hardware resources other than CPUs, Servers and Terminals
• CPC Class Codes: G06F 9/544 Buffers; Shared memory; Pipes
• CPC Class Codes: G06F 9/545 where tasks reside in different layers, e.g. user- and kernel-space

Abstract

The present invention provides a system, method, and computer program product that enables application instances to pass block mode storage requests directly to a physical I/O adapter without run-time involvement from the local operating system or hypervisor. In one aspect of the present invention, a mechanism is provided for determining whether a user space operation is a resource management operation of a work processing operation. If the user space operation is a resource management operation, appropriate functions are performed to either query, create, modify or destroy resource allocations in the I/O adapter. If the user space operation is a work processing operation, appropriate functions are performed to either create work queue entries and inform the I/O adapter of the work queue entries or to retrieve completion queue entries for work queue entries whose processing has been completed by the I/O adapter.

Claims

1. A method, in a data processing system, for managing user space operations, comprising:

receiving, in the data processing system, a user space operation from a user management interface;

determining if the user space operation is a resource management operation or a processing queue operation;

performing one or more resource management operations to either create, modify, query or destroy a resource allocation if the user space operation is a resource management operation; and

performing one or more processing queue operations to either insert a work queue entry in a work queue to send an out of user space input/output (I/O) operation directly to an I/O adapter without intervention by an operating system or system image, or to retrieve, directly from the I/O adapter without intervention by an operating system or system image, a completion queue entry from a completion queue for a completed out of user space input/output operation, if the user space operation is a processing queue operation.

2. The method of claim 1, wherein performing one or more resource management operations includes:

determining if the user space operation is a resource query operation;

retrieving attributes of a resource from the I/O adapter if the user space operation is a query operation; and

returning the retrieved attributes of the resource to the user management interface.

3. The method of claim 1, wherein performing one or more resource management operations includes:

determining if the user space operation is a resource create operation; and

allocating resources on the I/O adapter if the user space operation is a resource create operation.

4. The method of claim 3, wherein performing one or more resource management operations further includes determining if the I/O adapter has available resources for allocating based on the user space operation, wherein the resources are allocated only if the I/O adapter has available resources to be allocated.

5. The method of claim 1, wherein performing one or more resource management operations includes:

determining if the user space operation is a resource destroy operation; and

removing an allocation of resources on the I/O adapter if the user space operation is a resource destroy operation.

6. The method of claim 1, wherein performing one or more resource management operations includes:

determining if the user space operation is a resource modify operation; and

modifying one or more attributes associated with a resource allocation on the I/O adapter if the user space operation is a resource modify operation.

7. The method of claim 1, wherein performing one or more processing queue operations to either insert a work queue entry in a work queue or to retrieve a completion queue entry from a completion queue includes:

building and adding one or more work queue entries to a work queue associated with an application instance running on the data processing system and the I/O adapter; and

informing the I/O adapter that the one or more work queue entries have been added to the work queue.

8. The method of claim 7, wherein performing one or more processing queue operations further includes:

performing, in the I/O adapter, one or more validation checks to ensure that the application instance may access portions of a storage device referenced in the one or more work queue entries; and

performing, in the I/O adapter, one or more containment checks to ensure that the portions of the storage device referenced by the one or more work queue entries are within the portions of the storage device that have been allocated to the application instance.

9. The method of claim 8, wherein performing one or more processing queue operations further includes:

marking the one or more work queue entries as valid if the one or more validation checks complete successfully and the one or more containment checks complete successfully;

performing necessary I/O operations, in the I/O adapter, to complete processing of the one or more work queue entries that have been marked as valid; and

creating a completion queue entry, in a completion queue of the I/O adapter, for the one or more work queue entries whose processing in the I/O adapter has been completed.

10. The method of claim 1, wherein performing one or more processing queue operations includes:

polling a completion queue of the I/O adapter for any completion queue entries; and

retrieving and returning any completion queue entries in the completion queue to the user management interface.

11. A computer program product comprising a computer useable medium having a computer readable program, wherein the computer readable program, when executed on computing device, causes the computing device to:

receive a user space operation from a user management interface;

determine if the user space operation is a resource management operation or a processing queue operation;

perform one or more resource management operations to either create, modify, query or destroy a resource allocation if the user space operation is a resource management operation; and

perform one or more processing queue operations to either insert a work queue entry in a work queue to send an out of user space input/output (I/O) operation directly to an I/O adapter without intervention by an operating system or system image, or to retrieve, directly from the I/O adapter without intervention by an operating system or system image, a completion queue entry from a completion queue for a completed out of user space input/output operation, if the user space operation is a processing queue operation.

12. The computer program product of claim 11, wherein the computer readable program causes the computing device to perform one or more resource management operations by:

determining if the user space operation is a resource query operation;

retrieving attributes of a resource from the I/O adapter if the user space operation is a query operation; and

returning the retrieved attributes of the resource to the user management interface.

13. The computer program product of claim 11, wherein the computer readable program causes the computing device to perform one or more resource management operations by:

determining if the user space operation is a resource create operation; and

allocating resources on the I/O adapter if the user space operation is a resource create operation.

14. The computer program product of claim 13, wherein the computer readable program causes the computing device to perform one or more resource management operations by determining if the I/O adapter has available resources for allocating based on the user space operation, wherein the resources are allocated only if the I/O adapter has available resources to be allocated.

15. The computer program product of claim 11, wherein the computer readable program causes the computing device to perform one or more resource management operations by:

determining if the user space operation is a resource modify operation; and

modifying one or more attributes associated with a resource allocation on the I/O adapter if the user space operation is a resource modify operation.

16. The computer program product of claim 11, wherein the computer readable program causes the computing device to perform one or more processing queue operations to either insert a work queue entry in a work queue or to retrieve a completion queue entry from a completion queue by:

building and adding one or more work queue entries to a work queue associated with an application instance running on the data processing system and the I/O adapter; and

informing the I/O adapter that the one or more work queue entries have been added to the work queue.

17. The computer program product of claim 16, wherein the computer readable program causes the computing device to perform one or more processing queue operations by:

performing, in the I/O adapter, one or more validation checks to ensure that the application instance may access portions of a storage device referenced in the one or more work queue entries; and

performing, in the I/O adapter, one or more containment checks to ensure that the portions of the storage device referenced by the one or more work queue entries are within the portions of the storage device that have been allocated to the application instance.

18. The computer program product of claim 17, wherein the computer readable program causes the computing device to perform one or more processing queue operations by:

marking the one or more work queue entries as valid if the one or more validation checks complete successfully and the one or more containment checks complete successfully;

performing necessary I/O operations, in the I/O adapter, to complete processing of the one or more work queue entries that have been marked as valid; and

creating a completion queue entry, in a completion queue of the I/O adapter, for the one or more work queue entries whose processing in the I/O adapter has been completed.

19. The computer program product of claim 11, wherein the computer readable program causes the computing device to perform one or more processing queue operations by:

polling a completion queue of the I/O adapter for any completion queue entries; and

retrieving and returning any completion queue entries in the completion queue to the user management interface.

20. A data processing system, comprising:

a host system; and

an input/output (I/O) adapter coupled to the host system, wherein the host system;

receives a user space operation from a user management interface;

determines if the user space operation is a resource management operation or a processing queue operation;

performs one or more resource management operations to either create, modify, query or destroy a resource allocation if the user space operation is a resource management operation; and

performs one or more processing queue operations to either insert a work queue entry in a work queue to send an out of user space I/O operation directly to the I/O adapter without intervention by an operating system or system image, or to retrieve, directly from the I/O adapter without intervention by an operating system or system image, a completion queue entry from a completion queue for a completed out of user space input/output operation, if the user space operation is a processing queue operation.