Lazy deregistration protocol for a split socket stack

• US 20040010674A1
• Filed: 07/11/2002
• Published: 01/15/2004
• Est. Priority Date: 07/11/2002
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Recio, Renato John, Boyd, William Todd, Joseph, Douglas J.
• Granted Patent: US 6,823,437 B2
• Time in Patent Office: Days
• US Class Current: 711/170
• CPC Class Codes: G06F 12/023 Free address space management

Abstract

A method, computer program product, and distributed data processing system for lazy deregistration of memory regions. Specifically, the present invention is directed to memory regions that are written to and from by an Integrated Protocol Suite Offload Engine (IPSOE) in accordance with a preferred embodiment of the present invention. A mechanism is provided for lazy deregistration of memory regions once the region is no longer required for a specific data transfer being carried out by the IPSOE. Rather than deregistering a memory region after a data transfer has been carried out, the memory region remains registered for some selected period of time. After that selected period of time passes, the region is then deregistered. If a second data transfer using this memory region occurs while the memory region is still registered, the registration overhead is avoided for this second data transfer. This mechanism reduces the amount of CPU resources required for transferring data by allowing reuse of previously registered memory regions.

Claims

1. A method in a data processing system for managing memory, the method comprising:

responsive to a data transfer request from a requester, registering a section of memory for use in a data transfer to form a section of registered memory, wherein the section of memory is pinned ensuring that every page in the memory region is resident in memory; and

responsive to the data transfer completing, deregistering the section of memory after a selected period of time, wherein another data transfer request occurring before the selected period of time is handled using the section of memory without requiring a second registration of the memory region.

2. The method of claim 1, wherein the deregistering step comprises:

starting a timer set to expire after the selected period of time; and

deregistering the section of memory after the timer expires.

3. The method of claim 1, wherein the data transfer occurs using a Zcopy mechanism, wherein a data copy is unrequired to transfer the data to the requester.

4. The method of claim 1, wherein the data transfer takes place using a buffer located within the section of registered memory.

5. The method of claim 1 further comprising:

responsive to receiving the another data transfer request from another requester in which the data transfer request references a buffer contained in the section of memory, determining whether the section of memory is registered;

responsive to the memory being registered, determining whether the buffer is contained entirely within the section of memory; and

responsive to the buffer being contained entirely within the section of memory, performing another data transfer by reusing the buffer for the another data transfer request.

6. The method of claim 5 further comprising:

responsive to a first portion of the buffer being within the section of registered memory and a second portion of the buffer being outside the section of registered memory, comparing a size of the second portion of the buffer outside of the section of registered memory with a threshold; and

responsive to the size being less than or equal to the threshold, performing the another data transfer by reusing the first portion of the buffer for the another data transfer if the first portion of the buffer is still registered and copying the data in the second portion of the buffer to another buffer for the requester.

7. The method of claim 6 further comprising:

responsive to the size being greater than the threshold, registering the buffer; and

transferring the data to the another requestor by reusing the buffer if the buffer is still registered.

8. The method of claim 3, wherein the another data transfer request references the section of memory for use in transferring the data to the requester.

9. A method in a data processing system for managing memory, the method comprising:

receiving a request for a transfer of data from a consumer;

determining whether the request references a buffer;

responsive to the request referencing the buffer, determining whether the buffer is within a registered memory region for a first type of data transfer;

responsive to the buffer being within the registered memory region for the first type of transfer, transferring the data using the first type of transfer, wherein a deregistration timer used to deregister the memory region after a period of time is disabled until the transfer of data has completed;

responsive to a first portion of the buffer being inside the memory region and a second portion of the buffer being outside the registered memory region for the first type of transfer, comparing a size of the second portion to a threshold;

transferring data in the first portion of the buffer in the registered memory region using the first type of data transfer if the size of the second portion of the buffer is less than or equal to the threshold, wherein the deregistration timer is disabled; and

transferring data in the second portion of the buffer using the second type of data transfer if the size of the second portion is less than or equal to the threshold.

10. The method of claim 9 further comprising:

if the size of the second portion of the buffer is greater than the threshold, registering a memory region encompassing the second portion of the buffer to form a new registered memory region for the first type of data transfer; and

transferring the data using the first type of transfer, wherein the deregistration timer used to deregister the new registered memory region after a period of time is disabled until after the transfer of data has completed.

11. The method of claim 9, wherein the first type of data transfer uses a Zcopy mechanism and the second type of data transfer uses a Bcopy mechanism.

12. The method of claim 9 further comprising:

responsive to an expiration of the deregistration time, deregistering the registered memory region for use in the first type of transfer.

13. The method of claim 9, wherein the deregistration timer is disabled by preventing starting of the timer until the transfer of data completes.

14. The method of claim 9 further comprising:

responsive to the request referencing an unregistered buffer, comparing a size of the unregistered buffer to a threshold; and

responsive to the size of the unregistered buffer being greater than the threshold, transferring the data using the first type of data transfer.

15. The method of claim 13, wherein the first type of data transfer uses a Zcopy mechanism.

16. The method of claim 9, wherein the registered buffer is a Upper Layer Protocol buffer.

17. A data processing system for managing memory, the data processing system comprising:

a bus system;

a communications unit connected to the bus system;

a memory connected to the bus system, wherein the memory includes a set of instructions; and

a processing unit connected to the bus system, wherein the processing unit executes the set of instructions to register a section of memory for use in a data transfer to form a section of registered memory in which the section of registered memory is pinned ensuring that every page in the memory region is resident in memory in response to a data transfer request from a requester; and

deregister the section of memory after a selected period of time in which another data transfer request occurring before the selected period of time is handled using the section of memory without requiring a second registration of the memory region in response to the data transfer completing.

18. A data processing system for managing memory, the data processing system comprising:

a bus system;

a communications unit connected to the bus system;

a memory connected to the bus system, wherein the memory includes a set of instructions; and

a processing unit connected to the bus system, wherein the processing unit executes the set of instructions to receive a request for a transfer of data from a consumer;

determine whether the request references a buffer;

determine whether the buffer is within a registered memory region for a first type of data transfer in response to the request referencing the buffer;

transfer the data using the first type of transfer in which a deregistration timer used to deregister the memory region after a period of time is disabled until the transfer of data has completed in response to the buffer being within the registered memory region for the first type of transfer;

compare a size of the second portion to a threshold responsive to a first portion of the buffer being inside the memory region and a second portion of the buffer being outside the registered memory region for the first type of transfer;

transfer data in the first portion of the registered memory region using the first type of data transfer if the size of the second portion is less than or equal to the threshold in which the deregistration timer is disabled; and

transfer data in the second portion of the registered memory region using the second type of data transfer if the size of the second portion is less than or equal to the threshold.

19. A data processing system for managing memory, the data processing system comprising:

registering means, responsive to a data transfer request from a requester, for registering a section of memory for use in the data transfer to form a section of registered memory, wherein the section of memory is pinned ensuring consistent virtual-to-physical translations; and

deregistering means, responsive to the data transfer completing, for deregistering the section of memory after a selected period of time, wherein another data transfer request occurring before the selected period of time is handled using the section of memory without requiring a second registration of the memory region.

20. The data processing system of claim 19, wherein the deregistering means is a first deregistering means and comprises:

starting means for starting a timer set to expire after the selected period of time; and

means for deregistering the section of memory after the timer expires.

21. The data processing system of claim 19, wherein the data transfer occurs using a Zcopy mechanism, wherein a data copy is unrequired to transfer the data to the requester.

22. The data processing system of claim 19, wherein the data transfer takes place using a buffer located within the section of registered memory.

23. The data processing system of claim 20 further comprising:

first determining means, responsive to receiving the another data transfer request from another requestor in which the data transfer request references a buffer contained in the section of memory, for determining whether the section of memory is registered;

second determining means, responsive to the memory being registered, for determining whether the buffer is contained entirely within the section of memory; and

performing means, responsive to the buffer being contained entirely within the section of memory, for performing another data transfer by reusing the buffer for the another data transfer request if the buffer is still registered.

24. The data processing system of claim 23 further comprising:

comparing means, responsive to a first portion of the buffer being within the section of registered memory and a second portion of the buffer being outside the section of registered memory, for comparing a size of the second portion of the buffer outside of the section of registered memory with a threshold; and

performing means, responsive to the size being less than or equal to the threshold, for performing the another data transfer by reusing the first portion of the buffer for the another data transfer if the first portion of the buffer is still registered and copying the data in the second portion of the buffer to another buffer for the requester.

25. The data processing system of claim 24 wherein the registering means is a first registering means and further comprising:

second registering means, responsive to the size being greater than the threshold, for registering the buffer; and

transferring means for transferring the data to the another requester by reusing the buffer if the buffer is still registered.

26. The data processing system of claim 21, wherein the another data transfer request references the section of memory for use in transferring the data to the requester.

27. A data processing system for managing memory, the data processing system comprising:

receiving means for receiving a request for a transfer of data from a consumer;

first determining means for determining whether the request references a buffer;

second determining means, responsive to the request referencing the buffer, for determining whether the buffer is within a registered memory region for a first type of data transfer;

first transferring means, responsive to the buffer being within the registered memory region for the first type of transfer, for transferring the data using the first type of transfer, wherein a deregistration timer used to deregister the memory region after a period of time is disabled until the transfer of data has completed;

comparing means, responsive to a first portion of the buffer being inside the memory region and a second portion of the buffer being outside the registered memory region for the first type of transfer, for comparing a size of the second portion to a threshold;

second transferring means for transferring data in the first portion of the buffer in the registered memory region using the first type of data transfer if the size of the second portion of the buffer is less than or equal to the threshold, wherein the deregistration timer is disabled; and

third transferring means for transferring data in the second portion of the buffer using the second type of data transfer if the size of the second portion is less than or equal to the threshold.

28. The data processing system of claim 27 further comprising:

registering means, if the size of the second portion of the buffer is greater than the threshold, for registering a memory region encompassing the buffer to form a new registered memory region for the first type of data transfer; and

fourth transferring means for transferring the data using the first type of transfer, wherein the deregistration timer used to deregister the new registered memory region after a period of time is disabled until after the transfer of data has completed.

29. The data processing system of claim 27, wherein the first type of data transfer uses a Bcopy mechanism and the second type of data transfer uses a Zcopy mechanism.

30. The data processing system of claim 27 further comprising:

deregistering means, responsive to an expiration of the deregistration time, for deregistering the registered memory region for use in the first type of transfer.

31. The data processing system of claim 27, wherein the deregistration timer is disabled by preventing starting of the timer such until the transfer of data completes.

32. The data processing system of claim 27 wherein the comparing means is a first comparing means and further comprising:

second comparing means, responsive to the request referencing an unregistered buffer, for comparing a size of the unregistered buffer to a threshold; and

fourth transferring means, responsive to the size of the unregistered buffer being greater than the threshold, for transferring the data using the first type of data transfer.

33. The data processing system of claim 31, wherein the second type of data transfer uses a Zcopy mechanism.

34. The data processing system of claim 27, wherein the registered buffer is a Upper Layer Protocol buffer.

35. A computer program product in a computer readable medium for managing memory, the computer program product comprising:

first instructions, responsive to a data transfer request from a requester, for registering a section of memory for use in the data transfer to form a section of registered memory, wherein the section of memory is pinned ensuring consistent virtual-to-physical translations; and

second instructions, responsive to the data transfer completing, for deregistering the section of memory after a selected period of time, wherein another data transfer request occurring before the selected period of time is handled using the section of memory without requiring a second registration of the memory region.

36. A computer program product in a computer readable medium for managing memory, the computer program product comprising:

first instructions for receiving a request for a transfer of data from a consumer;

second instructions for determining whether the request references a buffer;

third instructions, responsive to the request referencing the buffer, for determining whether the buffer is within a registered memory region for a first type of data transfer;

fourth instructions, responsive to the buffer being within the registered memory region for the first type of transfer, for transferring the data using the first type of transfer, wherein a deregistration timer used to deregister the memory region after a period of time is disabled until the transfer of data has completed;

fifth instructions, responsive to a first portion of the buffer being inside the memory region and a second portion of the buffer being outside the registered memory region for the first type of transfer, for comparing a size of the second portion to a threshold;

sixth instructions for transferring data in the first portion of the registered memory region using the first type of data transfer if the size of the second portion is less than or equal to the threshold, wherein the deregistration timer is disabled; and

seventh instructions for transferring data in the second portion of the registered memory region using the second type of data transfer if the size of the second portion is less than or equal to the threshold.