On Tue, 8 May 2012 05:50:44 +0100, Al Viro <viro@xxxxxxxxxxxxxxxxxx> wrote: > On Tue, May 08, 2012 at 01:29:45PM +0930, Rusty Russell wrote: > > Optimizing the slow paths adds a lot of complexity. If you need to > > grab every lock often, you have other problems. > > Applied, but I'm not too happy about the situation with vfsmount_lock ;-/ > On kernels built for a lot of possible CPUs the loss of ..._online() > versions will get painful. My original motivation was to get rid of that cpumask_t (and replace it with a cpumask_var_t). A simple enough patch, but I couldn't bring myself to leave that complex logic in place without clear justification. > OTOH, we can always put the map + single > spinlock + single notifier into lglock.c and reproduce the old logics. > I'll do a patch along those lines and put it on a separate branch; > then we'll be able to test and compare. I'll be interested in the results: virtual systems are classic for wanting large # of CPUs which aren't actually online, so we might actually care. I'd also like to get rid of the cpu_possible_map altogether, and just have NR_CPUS/nr_cpu_ids, since last I checked no arch really wants sparse numbers. Cheers, Rusty. -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
