Hello, Andrew Morton wrote: > On Wed, 24 Jun 2009 22:30:06 +0900 > Tejun Heo <tj@xxxxxxxxxx> wrote: > >> This patchset is available in the following git tree and will be >> published in for-next if there's no major objection. It might get >> rebased before going into for-next. >> >> git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu.git lpage-numa > > <tries to read the patches> > > Boy, this stuff is complicated. Does it all work? I sure hope so. > The Impact: lines were useful :) Eh.. well, it looks like it's going the way of dodo tho. > I assume from the tremendous number of for_each_possible_cpu()s that > CPU hotplug awareness won't be happening. > > Do we have a feeling for the amount of wastage here? If > > num_possible_cpus() - num_online_cpus() == N > > and N is large, what did it cost? > > And what are reasonable values of N? The goal is to eventually implement has_ever_been_online_cpus (any better naming?) mask and allocate only for those cpus. I think I mentioned it in one of the patch descriptions but anyways the unit_map and lpage improvments implemented in this patchset will be used for that purpose. The plan is to treat possible but offline cpus as if they belong to separate group such that they don't end up sharing the same PMD page and later when those cpus come up the generic 4k mapping can kick in and map them. Thanks. -- tejun -- To unsubscribe from this list: send the line "unsubscribe linux-arch" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
