Messages in this thread | | | Date | Mon, 30 Jul 2007 07:28:42 -0400 (EDT) | From | Steven Rostedt <> | Subject | Re: [PATCH -rt 2/9] Dont allow non-threaded softirqs and threaded hardirqs |
| |
-- On Mon, 30 Jul 2007, Ingo Molnar wrote: > > From: Steven Rostedt <rostedt@goodmis.org> > > > > I think this was sent before, and it did cause problems before. Would > > there be *any* reason to have non-threaded softirqs but threaded > > hardirqs. I can see lots of issues with that. > > please elaborate in precise terms: what issues can you see? >
Hi Ingo,
I don't remember the exact details, I can try to find the thread. But I remember someone was having their system lock up strangly. We later found that they had softirqs as normal softirqs and interrupts as threads. I think there was some driver that didn't expect the softirq to preempt the irq handler. Perhaps the softirq was using spin_lock_irq while the irq thread was just using spin_lock, which I can see as being something normal.
The standard Linux does not expect an interrupt to be preempted by a softirq, and with interrupts as threads but not softirqs, I can see that happening a lot.
-- Steve
- 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/
| |