Messages in this thread | | | Subject | Re: 8-CPU (SMP) #s for lockfree rtcache | From | Alan Cox <> | Date | 28 May 2002 19:10:47 +0100 |
| |
On Tue, 2002-05-28 at 17:34, Andi Kleen wrote: > And gain tons of new atomic_incs and decs everywhere in the process? > I would prefer RCU.
RCU is a great way to make sure people get module unloading *wrong*. It has to be simple for the driver authors. The odd locked operation on things like open() of a device file is not a performance issue, not remotely.
Lots of people write drivers, many of them not SMP kernel locking gurus who have time to understand RCU and when they can or cannot sleep, and what happens if their unload is pre-empted and RCU is in use. The kernel core has to provide a clean easy interface. The network code is a superb example of this. All the hard thinking is done outside of the driver, at least unless you choose to join in that thinking to get the last scraps of performance.
Alan
- 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/
| |