Messages in this thread | | | Date | Wed, 22 Mar 2000 00:56:06 +0100 | From | Jamie Lokier <> | Subject | Re: new IRQ scalability changes in 2.3.48 |
| |
Linus Torvalds wrote: > In practice, there are places that know how spinlocks work, and do things > with them that would be illegal in the preemptive UP kernel. Nor many, and > maybe I'm pessimistic, but I would not be in the least surprised if some > random driver somewhere does something like > > spin_lock_irq(&io_request_lock); > ... > spin_unlock(&io_request_lock); > ... > __sti(); > > which is entirely legal on SMP. But it would be hugely illegal on threaded > UP with the spinlock optimizations, because the "unlock" would modify the > spinlock count, but the optimzied "lock_irq" would not.
At least those things are easily caught with some spinlock debugging code.
-- Jamie
- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.rutgers.edu Please read the FAQ at http://www.tux.org/lkml/
| |