On Wednesday 14 November 2007 06:22, David Brownell wrote: > On Tuesday 13 November 2007, Ingo Molnar wrote: > > * David Brownell <[EMAIL PROTECTED]> wrote: > > > > > I speculate that either the design has changed (without fanfare), > > > > > or else that stuff is in RT kernels and has not yet gone upstream. > > > > > > > > Well whatever. We shouldn't have to resort to caller-side party > > > > tricks like this to get acceptable performance. > > > > > > I'd be happy if, as originally presented, it were possible to just > > > pass a raw_spinlock_t to spin_lock_irqsave() and friends. > > > > that's a spinlock type abstraction of PREEMPT_RT, not of mainline.
Even when you're talking about the -rt tree, I suspect you really shouldn't be using raw spinlocks, right? I mean, if you have a timing critical operation, then you should ensure you have priorities set correctly so that you simply don't get preempted. By using a raw_spinlock_t, you're saying that you're more important than anyone else (for the period of the critical section) including processes which the user has explicitly set to a higher priority. If you get preempted, then you should be happy, because <standard RTOS nuclear power plant scenario> didn't occur. > Any reason that stuff shouldn't move into mainline? This sort of raw_spinlock_t arms race throughout drivers/ would be a huge reason not to move it into mainline. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
