CPU_NEED_RESCHED(9) Kernel Developer's Manual CPU_NEED_RESCHED(9)
NAME
cpu_need_reschedcontext switch notification
SYNOPSIS
#include <sys/cpu.h>
void
cpu_need_resched(struct cpu_info *ci, int flags);
DESCRIPTION
The cpu_need_resched() function is the machine-independent interface for the scheduler to notify machine-dependent code that a context switch from the current LWP, on the cpu ci, is required. This event may occur if a higher priority LWP appears on the run queue or if the current LWP has exceeded its time slice.
 
If RESCHED_IMMED flag is specified in flags, machine-dependent code should make a context switch happen as soon as possible. In that case, for example, if ci is not the current processor, cpu_need_resched() typically issues an inter processor call to the processor to make it notice the need of a context switch as soon as possible.
 
Specifically, the cpu_need_resched() function will perform the following operations:
Set a per-processor flag which is checked by userret(9) when returning to user-mode execution.
Post an asynchronous software trap (AST).
Send an inter processor interrupt to wake up cpu_idle(9).
SEE ALSO