Date: Thu, 26 Mar 2015 15:30:01 +0100 From: "J. Hannken-Illjes" <hann...@eis.cs.tu-bs.de>
On 26 Mar 2015, at 13:13, Taylor R Campbell <campbell+netbsd-tech-k...@mumble.net> wrote: > The attached patch implements the following extension to pmap(9) on > x86 and uses it in DRM[*]. The implementation uses a linear list of > pv-tracked ranges, since it is expected to be short (one to three > elements). The list is managed with pserialize(9) so it adds no > locking overhead to existing pmap operations that need to look up > entries in it. If you plan to use pserialize here it is time to change pserialize_perform() to not kpause() every xc_broadcast. Currently pserialize_perform() takes at least two ticks to complete. No objection to making pserialize(9) faster, but for this P->V tracking code, pserialize_perform happens only when you are, e.g., detaching a device -- which is about the least performance-critical path I can imagine.
