On Tue, May 29, 2012 at 07:48:06PM +0200, Peter Zijlstra wrote: > On Tue, 2012-05-29 at 19:44 +0200, Andrea Arcangeli wrote: > > > > But it'd be totally bad not to do the hard bindings to the cpu_s_ of > > the node, and not using PF_THREAD_BOUND would just allow userland to > > shoot itself in the foot. I mean if PF_THREAD_BOUND wouldn't exist > > already I wouldn't add it, but considering somebody bothered to > > implement it for the sake to make userland root user "safer", it'd be > > really silly not to take advantage of that for knuma_migrated too > > (even if it binds to more than 1 CPU). > > No, I'm absolutely ok with the user shooting himself in the foot. The > thing exists because you can crash stuff if you get it wrong with > per-cpu. > > Crashing is not good, worse performance is his own damn fault. Some people don't like root to write to /dev/mem or rm -r / either. I'm not in that camp, but if you're not in that camp, then you should _never_ care to set PF_THREAD_BOUND, no matter if it's about crashing or just slowing down the kernel. If such a thing exists, well using it to avoid the user either to crash or to screw with the system performance, can only be a bonus. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>