International Business Machines Corporation

Linda Djohan

Douglas Michael Zobre

A system and method for providing two or more contending processes with concurrent access to a shared resource having a primary list of elements and a list access count, with direct association between at least first and second consecutive elements each having a use counter, wherein resource access includes an obligation to perform an access completion operation. The method comprises the steps of marking the first element as ready to be deleted upon receiving a signal from a traversing one of the contending processes. Next, the first element ready to be deleted is placed on a delete list, is unchained from the primary list and is moved the delete list to an unchained list. A determination is made whether the list access counter is equal to zero: if not, the list access counter is decremented and the system waits for another contending process to access the primary list; if so, an obligation is passed to the traversing process to perform an access completion operation by: determining whether the second element's use counter is equal to zero: if not, the list access counter is decremented and the system waits for another contending process to access the primary list; if so, the first element can be released thereby completing its deletion or it can be put a free list, thereby indicating that the first element is ready to be released. Once all elements are moved from the unchained list and placed on the free list, the free list can be released in its entirety.

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West Bloomfield, MI, United States of America

Linda Djohan