On Tue, Oct 28, 2014 at 07:05:01PM -0700, Jarno Rajahalme wrote: > > > On Oct 28, 2014, at 4:36 PM, Ben Pfaff <b...@nicira.com> wrote: > > > >> On Fri, Oct 24, 2014 at 01:36:40PM -0700, Jarno Rajahalme wrote: > >> Previously, accurate iteration required writers to be excluded during > >> iteration. This patch changes the structure of the classifier by > >> moving the list of rules from struct cls_match to struct cls_subtable. > >> The list element is also moved from the struct cls_match to struct > >> cls_rule, which makes iteration more straightforward, and allows the > >> iterators to remain ignorant of the internals of the cls_match. These > >> changes allow iteration of rules in the classifier by traversing the > >> RCU-friendly subtables vector, and the rculist of rules in each > >> subtable. Classifier modifications may be performed concurrently, but > >> whether or not the concurrent iterator sees those changes depends on > >> the timing of change. This is similar to having writers excluded by a > >> mutex, where visibility of changes depends on the timing of mutex > >> acquisition. > >> > >> The subtable's rculist also allows to make > >> classifier_find_rule_exactly() and classifier_rule_overlaps() > >> lockless. > >> > >> Signed-off-by: Jarno Rajahalme <jrajaha...@nicira.com> > > > > I *think* I follow what's going on here, but just to be sure, let me > > try to explain it. After this patch, the subtable has a list of every > > rule in the subtable, as 'rules_list'. The rules in the list are in > > no particular order, except that rules with identical match criteria > > are in subsequent positions. Is that correct? > > Yes :-)
The conjunctive match series uses the list of lower-priority rules in lookup. I think that this patch, as-is, would make that a lot more expensive, because it's no longer cheap to tell whether the next rule in the list has the same match. I guess one could still mark boundaries somehow; do you have an idea? _______________________________________________ dev mailing list dev@openvswitch.org http://openvswitch.org/mailman/listinfo/dev
