From: Paul Mackerras <pau...@samba.org> Date: Sat, 9 May 2009 09:34:29 +1000
> If a soft irq is raised in process context, raise_softirq() in > kernel/softirq.c calls wakeup_softirqd() to make sure that ksoftirqd > runs soon to process the soft irq. So what would happen is that we > would see the TIF_RESCHED_PENDING flag on the current task in the > syscall exit path and call schedule() which would switch to ksoftirqd > to process the soft irq (if it hasn't already been processed by that > stage). > > If the soft irq is raised in interrupt context, then the soft irq gets > run via the do_softirq() call in irq_exit(), as you saw. > > The soft irq stuff is pretty much all generic code these days, except > for the code to switch to the softirq stack. Grumble, when did that happen :-( That's horrible for latency compared to handling it directly in the trap return path. _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@ozlabs.org https://ozlabs.org/mailman/listinfo/linuxppc-dev
