Input/output completion system and method for a data processing platform
View Patent ↗A mechanism is disclosed for performing I/O operations using queue banks within a data processing system that supports multiple processing partitions. A queue bank is a re-useable area of memory allocated for performing I/O operations. All memory locking and address-translation functions are generally performed only once for a queue bank to reduce system overhead. After a queue bank has been used to perform an I/O operation, some processing is performed to make it available for re-use. This processing determines whether the queue bank contains memory that is being removed from a current processing partition. If so, a delay is imposed so that the queue bank is not made available for immediate re-use. This creates a window of time wherein all queue banks that contain the affected memory are inactive, thereby allowing the affected memory to be removed from the partition without halting on-going I/O activity.
1. Within a data processing system that supports multiple processing partitions, a computer-implemented method for managing I/O operations, comprising:
determining whether a queue bank that has been dedicated for use in performing I/O operations is currently waiting to be re-used;
making the queue bank available for re-use in performing the I/O operations in a manner that is based upon whether modifications that affect the queue bank are being made to a processing partition containing the queue bank;
selecting memory for removal from the processing partition containing the queue bank;
determining that the queue bank includes at least part of the selected memory;
ensuring that the queue bank is not selected for re-use before the selected memory has been removed from the processing partition containing the queue bank by placing the queue bank at an end of an available queue such that the queue bank will not be selected for re-use before the selected memory has been removed from the processing partition containing the queue bank.
2. The method of claim 1 , further comprising:
determining that no memory containing the queue bank has been selected for removal from the processing partition containing the queue bank; and
allowing the queue bank to immediately be made available for re-use following the determination.
3. The method of claim 2 , further comprising:
caching addresses of the queue bank during execution of a previous I/O operation that used the queue bank; and
selecting the queue bank for re-use in another I/O operation while the addresses of the queue bank are still cached, whereby the other I/O operation is completed more efficiently.
4. The method of claim 2 , further comprising placing the queue bank at a beginning of an available queue such that the queue bank may be selected for re-use substantially immediately.
5. The method of claim 1 , further comprising:
allocating one or more pages of storage space for inclusion in the queue bank;
performing virtual-to-real address translation for each of the one or more pages; and
locking each of the one or more pages in a memory of the data processing system.
6. The method of claim 1 , wherein the modifications include removing memory from the processing partition containing the queue bank, at least some of the memory being allocated for use by the queue bank, and wherein if it is determined the modifications are being made, making the queue bank unavailable for immediate re-use.
7. The method of claim 1 , wherein the steps of claim 1 are performed for multiple queue banks, and further comprising removing memory from the processing partition, wherein the memory was previously allocated for use by one or more of the queue banks, the memory being removed only after it has been determined that all of the one or more of the queue banks are no longer involved in performing any of the I/O operations.