CPU_NEED_RESCHED(9)    NetBSD Kernel Developer's Manual    CPU_NEED_RESCHED(9)

NAME
     cpu_need_resched -- context 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() typi-
     cally issues an inter processor call to the processor to make it notice
     the need of a context switch as soon as possible.

EXAMPLES
     Specifically, the cpu_need_resched() function will perform the following
     operations:

           o   Set a per-processor flag which is checked by userret(9) when
               returning to user-mode execution.

           o   Post an asynchronous software trap (AST).

           o   Send an inter processor interrupt to wake up cpu_idle().

SEE ALSO
     sched_4bsd(9), userret(9)

NetBSD 5.0_STABLE                May 18, 2007                NetBSD 5.0_STABLE
