Adapting RCU for real-time operating system usage
First Claim
1. A method for operating a single central processing unit (CPU) computer system comprising:
- traversing a read-copy-update (RCU) locked data structure by a first function without a second function accessing the data structure being made aware of said traversal;
removing an element from said data structure;
determining if said element can be immediately freed from memory, including determining if said element can be removed from said data structure and freed from memory by said second function operating concurrently with said first function; and
immediately freeing said element from memory in response to a positive determination.
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Accused Products
Abstract
A system and method is provided to support immediate freeing of a designated element from memory. Following a process of designating an element for removal from a data-structure, conditional limitations are used to determine if immediate freeing of the element from memory is available. The conditional limitations include determining that the instruction originates from a uniprocessor computer system. In addition, the conditional limitations include a determination as to whether a call_rcu primitive or synchronize_kernel primitive may be omitted, or whether the computer implemented instruction is operating in an interrupt handler. If the conditional limitations are met, the designated element may be immediately freed from memory.
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Citations
16 Claims
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1. A method for operating a single central processing unit (CPU) computer system comprising:
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traversing a read-copy-update (RCU) locked data structure by a first function without a second function accessing the data structure being made aware of said traversal; removing an element from said data structure; determining if said element can be immediately freed from memory, including determining if said element can be removed from said data structure and freed from memory by said second function operating concurrently with said first function; and immediately freeing said element from memory in response to a positive determination. - View Dependent Claims (2, 3, 4, 5)
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6. A single central processing unit (CPU) computer system comprising:
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a first function adapted to traverse a read-copy-update (RCU) locked data structure without awareness by a second function accessing the data structure of said traversal; an element adapted to be removed from said data structure; a memory manager adapted to determine if said element can be immediately freed from memory and to determine if said element can be removed from said data structure and freed from memory by said second function adapted to operate concurrently with said first function; and a removal manager adapted to immediately free said element from memory in response to receipt of a positive determination from said memory manager. - View Dependent Claims (7, 8, 9, 10)
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11. An article comprising:
- a computer-readable medium including computer program instructions configured to operate a single central processing unit (CPU) computer system, said instructions comprising;
instructions to traverse a read-copy-update (RCU) locked data structure by a first function without awareness by some other processes of said traversal;
instructions to remove an element from said data structure;
instructions to determine if said element can be immediately freed from memory, including instructions to determine if said element can be removed from said data structure and freed from memory by a second function concurrently operating in said data structure with said first function; and
instructions to immediately free said element from memory in response to a positive determination. - View Dependent Claims (12, 13, 14, 15, 16)
- a computer-readable medium including computer program instructions configured to operate a single central processing unit (CPU) computer system, said instructions comprising;
Specification