Method and apparatus for controlling exclusive access to a shared resource in a data storage system
First Claim
1. A method for controlling exclusive access to a resource shared by a plurality of processors in a data storage system, comprising:
- providing for each processor a system lock procedure to permit a processor executing the system lock procedure to obtain a lock on the shared resource preventing other processors from accessing the shared resource; and
providing for each processor a faked lock procedure to indicate to the system lock procedure that a processor executing the faked lock procedure has a lock on the shared resource where such a lock does not exist, and wherein the faked lock procedure does not prevent other processors from accessing the shared resource.
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Accused Products
Abstract
A method for controlling exclusive access to a resource shared by multiple processors in a data storage system includes providing a system lock procedure to permit a processor to obtain a lock on the shared resource preventing other processors from accessing the shared resource and providing a faked lock procedure to indicate to the system lock procedure that a processor has a lock on the shared resource where such a lock does not exist, and wherein the faked lock procedure prevents another processor from obtaining the lock on the shared resource, but does not prevent other processors from accessing the shared resource. A data storage system according to the invention includes a shared resource, a plurality of processors coupled to the shared resource through a communication channel, and a lock services procedure providing the system lock procedure and the faked lock procedure. In one embodiment, the shared resource is a cache and the system lock procedure permits a processor to lock the entire cache whereas the faked lock procedure is implemented by a processor seeking exclusive access of a cache slot.
117 Citations
21 Claims
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1. A method for controlling exclusive access to a resource shared by a plurality of processors in a data storage system, comprising:
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providing for each processor a system lock procedure to permit a processor executing the system lock procedure to obtain a lock on the shared resource preventing other processors from accessing the shared resource; and providing for each processor a faked lock procedure to indicate to the system lock procedure that a processor executing the faked lock procedure has a lock on the shared resource where such a lock does not exist, and wherein the faked lock procedure does not prevent other processors from accessing the shared resource. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A data storage system comprising:
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a shared resource; a plurality of processors coupled to the shared resource through a communication channel; and a lock services procedure implemented in each of the processors and comprising a system lock procedure to permit a processor executing the lock services procedure to obtain a lock on a shared resource preventing other processors from accessing the shared resource and a faked lock procedure to indicate to the system lock procedure a lock on the shared resource by the processor where such a lock does not exist and wherein the faked lock procedure does not prevent other processors from accessing the shared resource. - View Dependent Claims (14, 15, 16, 17)
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18. A method for controlling exclusive access to a resource shared by a plurality of processors in a data storage system, comprising:
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permitting a lock seeking processor to obtain a lock on the shared resource preventing other processors from accessing the shared resource; and falsely indicating to the lock seeking processor that another processor seeking to change a state of a portion of the shared resource has a lock on the shared resource to prevent the lock seeking processor from obtaining the lock on the shared resource. - View Dependent Claims (19, 20, 21)
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Specification