On Wed, 21 Mar 2007 12:27:17 -0700 (PDT), Roland McGrath <roland@xxxxxxxxxx> wrote: > FWIW, I have taken to CONFIG_PREEMPT=y in my hacking kernels because it > exposed on my clunky test machines bugs that were otherwise reproduced only > on big honking machines with lots of parallelism. [...] It helps with that, but I just don't trust it to work at all times. It's a really kludgy code from MontaVista, developed with embedded devices in mind. It's a certified miracle that it boots on SMP at all. That said, I love to hoist it onto others. It really helps to flush mb() from drivers. Before, it always was a hassle to persuade driver writers that they must not do it; not worth the trouble. Now you just turn the preempt on and voila, the box crashes. Heck, I had preempt find a bug in ub once (guess what... used mb() there too -- nobody is perfect). But running it on a production box is pure madness, IMHO. -- Pete
