Arguments

Description

Enter idle mode, in other words, -leave- the mode in which RCU read-side critical sections can occur. (Though RCU read-side critical sections can occur in irq handlers in idle, a possibility handled by irq_enter and irq_exit.)

We crowbar the ->dynticks_nesting field to zero to allow for the possibility of usermode upcalls having messed up our count of interrupt nesting level during the prior busy period.