Patent ID: 9256476
Filing Date: 2016-02-09
CPC Classification: G06F

Claim Text:
1. A system, comprising: one or more processors; a memory coupled to said one or more processors, said memory including a computer useable medium tangibly embodying at least one program of instructions executable by said processor to perform operations for expediting unloading of an operating system kernel module that executes read-copy update (RCU) callback processing code, said operations comprising: performing regular periodic grace period detection processing to detect the end of grace periods in which each of said one or more processors has passed through a quiescent state; wherein said expediting unloading of the operating system kernel module further comprising: wherein said system is one of a uniprocessor system that runs a non-preemptible operating system kernel, a multiprocessor system that runs a non-preemptible operating system kernel, or a multiprocessor that runs a preemptible operating system kernel; wherein if said system is a uniprocessor system that runs a non-preemptible operating system kernel, said callback processing code runs in a deferred non-process context of said operating system kernel, and said expediting operation comprises invoking said deferred non-process context to force said callback processing code to execute; wherein if said system is a multiprocessor system that runs a non-preemptible operating system kernel, and said expediting operation comprises forcing each processor to note a new grace period and forcing a quiescent state on each processor, said forcing a quiescent state including implementing a rescheduling operation on each processor, and wherein said expediting operation is repeated until said RCU callback is processed; and wherein if said system is a multiprocessor system that runs a preemptible operating system kernel, and said expediting operation comprises forcing each processor to note a new grace period and forcing a quiescent state on each processor, said forcing a quiescent state including implementing a priority boost for blocked reader tasks that are preventing completion of said grace period.