Date: Fri, 9 Mar 2001 21:09:13 +0100 From: Jamie Lokier <lk@tantalophile.demon.co.uk> To: Rik van Riel <riel@conectiva.com.br> Subject: Re: static scheduling - SCHED_IDLE? Rik van Riel wrote: > > Just raise the priority whenever the task's in kernel mode. Problem > > solved. > > Remember that a task schedules itself out at the timer interrupt, > in kernel/sched.c::schedule() ... which is kernel mode ;) Even nicer. On x86 change this: reschedule: call SYMBOL_NAME(schedule) # test jmp ret_from_sys_call to this: reschedule: orl $PF_HONOUR_LOW_PRIORITY,flags(%ebx) call SYMBOL_NAME(schedule) # test andl $~PF_HONOUR_LOW_PRIORITY,flags(%ebx) jmp ret_from_sys_call (You get the idea; this isn't the best implementation). I think this code can only be reached in two ways: 1. An interrupt, exception, page fault etc. that is returning to user space. 2. A system call, whatever space it's from. In both these cases, no critical locks will be held, right? -- Jamie - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/