what i got is ............ Quiescent State: A point in the code where all of the current CPU's temporary variables that were previously in use in a critical section are dead. In a non-preemptive Linux kernel, a context switch is a quiescent state for CPUs. In a preemptive Linux kernel, rcu_read_lock() and rcu_read_unlock() suppress preemption for short read-side critical sections, so that context switch is still a quiescent state with respect to these read-side critical sections. Although there are implementations of RCU that do not require preemption to be suppressed [ Gamsa99, McK02a], they can be prone to excessively long grace periods. " www.usenix.org/events/usenix03/tech/freenix03/full_papers/arcangeli/arcangeli_html/node4.html " seriously i don't know what it is telling........ if you can understood....correct me
Quiescent state is a state when the kernel "forgets" all the kernel data structures, say in the case of: Switching back to user space Running in idle state Processor is disabled. By forget, we mean that they would not be refered again, and if refered a fresh lookup (of pointers etc.) will be done. The quiescent state of all processors leads to a quiescent period. This is a period when each of the processors have gone through a quiescent state atleast once. This concept is useful in a new technique of lock avoiding (read: _not replacement_) technique called Read Copy Update (RCU). Read more on RCU on lwn.net and you would get clear on these concepts. you should get more docs on the IBM docs since they are the ones who contributed the technology to Linux Kernel. Regards, -- Goldwyn -- Kernelnewbies: Help each other learn about the Linux kernel. Archive: http://mail.nl.linux.org/kernelnewbies/ FAQ: http://kernelnewbies.org/faq/
