Patent ID: 7644409

Claim:
A method for accessing a shared resource of a computerized system, the method comprising: running a first portion of a first thread within the computerized system, the first portion (i) requesting a lock on the shared resource and (ii) directing the computerized system to make operations of a second thread visible in a correct order, the correct order preventing an exclusion failure, the first portion of the thread representing at least instructions that perform the steps of requesting and directing; making operations of the second thread visible in the correct order in response to the first portion of the first thread running within the computerized system, the second thread visible to at least one other processor; and running a second portion of the first thread within the computerized system to determine whether the first thread has obtained the lock on the shared resource, the second portion of the thread representing at least one instruction that performs the step of determining whether the first thread has obtained the lock on the shared resource; wherein running the first portion of the first thread includes: performing a store operation which stores a lock request value in a memory variable which is accessible by both the first and second threads; performing a memory barrier operation which guarantees execution of the store operation before a next operation; and performing, as the next operation, a system call which directs the computerized system to make operations of the second thread visible in the correct order; wherein performing the system call includes: executing operating system code to change protection of a page of memory of the computerized system.