Method for associating windows to regions for infiniband

• US 20020178339A1
• Filed: 05/24/2001
• Published: 11/28/2002
• Est. Priority Date: 05/24/2001
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Recio, Renato John, Craddock, David F., Beukema, Bruce Leroy, Gregg, Thomas Anthony
• Granted Patent: US 6,691,217 B2
• Time in Patent Office: Days
• US Class Current: 711/203
• CPC Class Codes: G06F 12/0261 using reference counting
• CPC Class Codes: G06F 12/1081 for peripheral access to main memory, e.g. direct memory access [DMA]
• CPC Class Codes: Y10S 707/99953 Recoverability
• CPC Class Codes: Y10S 707/99956 File allocation

Abstract

A method, program and system for associating memory windows with memory regions in an infiniband data storage system are provided. The invention comprises registering a Memory Region, wherein the Memory Region is a set of virtually contiguous memory addresses defined by a virtual address and length. The system then establishes and maintains a Window Reference Count (WRC) for the Memory Region, which tracks the number of Memory Windows which are bound to the Memory Region. When the system binds a Memory Window to the Memory Region, the value of the WRC is incremented. When a Memory Window is unbound from the Memory Region, the value of the WRC is decremented. If no Memory Windows are bound to the Memory Region, the value of the WRC is zero. The Memory Region is not deregistered unless the value of the WRC equals zero.

Claims

1. A method for associating memory windows with memory regions in a data storage system, the method comprising:

registering a memory region, wherein the memory region is a set of virtually contiguous memory addresses defined by a virtual address and length;

establishing a window reference count for the memory region, wherein the value of the window reference count corresponds to a plurality of memory windows bound to the memory region;

binding a first memory window to the memory region and incrementing the value of the window reference count; and

binding a second memory window to the memory region and incrementing the value of the window reference count.

2. The method according to claim 1, further comprising:

unbinding a bound memory window from the memory region and decrementing the value of the window reference count.

3. The method according to claim 1, further comprising:

deregistering a memory region;

examining the window reference count;

unbinding any memory windows bound to the memory region, as determined by the value of the window reference count; and

deregistering the memory region only if the window reference count has a value of zero.

4. The method according to claim 3, wherein the step of unbinding memory windows further comprises:

returning an error signal if the value of the window reference count is non-zero; and

suspending deregistration of the memory region until an operating system kernel clean-up code has unbound all memory windows from the memory region.

5. The method according to claim 3, wherein the step of unbinding memory windows further comprises:

returning an error signal if the value of the window registration count is non-zero; and

invalidating all bound memory windows and allowing memory region deregistration to proceed.

6. A computer program product in a computer readable medium for use in a data processing system, for associating memory windows with memory regions in a data storage system, the computer program product comprising:

instructions for registering a memory region, wherein the memory region is a set of virtually contiguous memory addresses defined by a virtual address and length;

instructions for establishing a window reference count for the memory region, wherein the value of the window reference count corresponds to a plurality of memory windows bound to the memory region;

instructions for binding a first memory window to the memory region and incrementing the value of the window reference count; and

instructions for binding a second memory window to the memory region and incrementing the value of the window reference count.

7. The computer program product according to claim 6, further comprising:

instructions for unbinding a bound memory window from the memory region and decrementing the value of the window reference count.

8. The computer program product according to claim 6, further comprising:

instructions for deregistering a memory region;

instructions for examining the window reference count;

instructions for unbinding any memory windows bound to the memory region, as determined by the value of the window reference count; and

instructions for deregistering the memory region only if the window reference count has a value of zero.

9. The computer program product according to claim 8, wherein the instructions for unbinding memory windows further comprise:

instructions for returning an error signal if the value of the window reference count is non-zero; and

instructions for suspending deregistration of the memory region until an operating system kernel clean-up code has unbound all memory windows from the memory region.

10. The computer program product according to claim 8, wherein the instructions for unbinding memory windows further comprise:

instructions for returning an error signal if the value of the window reference count is non-zero; and

instructions for invalidating all bound memory windows and allowing memory region deregistration to proceed.

11. An apparatus for associating memory windows with memory regions in a data storage system, the apparatus comprising:

a first register which registers a memory region, wherein the memory region is a set of virtually contiguous memory addresses defined by a virtual address and length;

a second register which maintains a window reference count for the memory region, wherein the value of the window reference count corresponds to a plurality of memory windows bound to the memory region;

a first binding component which binds a first memory window to the memory region and increments the value of the window reference count; and

a second binding component which binds a second memory window to the memory region and increments the value of the window reference count.

12. The apparatus according to claim 11, further comprising:

an unbinding component which unbinds a bound memory window from the memory region and decrements the value of the window reference count.

13. The apparatus according to claim 11, further comprising:

a first deregistration component which deregisters a memory region;

an examining component which examines the window reference count;

an unbinding component which unbinds any memory windows bound to the memory region; and

a second deregistration component which deregisters the memory region only if the window reference count has a value of zero.

14. The apparatus according to claim 13, wherein the unbinding component which unbind memory windows further comprises:

a response component which returns an error signal; and

a regulating component which suspends deregistration of the memory region until an operating system kernel clean-up code has unbound all memory windows from the memory region.

15. The apparatus according to claim 13, wherein the unbinding component which unbinds memory windows further comprises:

a response component which returns an error signal; and

an invalidation component which invalidates all bound memory windows and allowing memory region deregistration to proceed.