On Sep 4, 2013, at 12:37 PM, Ethan Jackson <et...@nicira.com> wrote:
…
> @@ -240,15 +242,18 @@ struct rule {
> struct heap_node evg_node; /* In eviction_group's "rules" heap. */
> struct eviction_group *eviction_group; /* NULL if not in any group. */
>
> - /* The evict lock is used to prevent rules from being evicted while child
> - * threads are using them to xlate flows. A read lock means the rule is
> - * currently being used. A write lock means the rule is in the process
> of
> - * being evicted and should be considered gone. A rule will not be
> evicted
> - * unless both its own and its classifiers write locks are held.
> - * Therefore, while holding a classifier readlock, one can be assured
> that
> - * even write locked rules are safe. */
> - struct ovs_rwlock evict;
> + /* The rwlock is used to protect those elements in struct rule which are
> + * accessed by multiple threads. While maintaing a pointer to struct
> rule,
> + * threads are requires to hold a readlock. The main ofproto code is
> + * guarnated not to evict the rule, or change any of the elements
> "Guarded
/s/guarnated/guaranteed/
> + * by rwlock" without holding the writelock.
> + *
> + * A rule will not be evicted unless both its own and its classifier's
> + * write locks are held. Therefore, while holding a classifier readlock,
> + * one can be assured that ewrite locked rules are safe to reference. */
/s/ewrite/write/
> + struct ovs_rwlock rwlock;
>
> + /* Guarded by rwlock. */
> struct ofpact *ofpacts; /* Sequence of "struct ofpacts". */
> unsigned int ofpacts_len; /* Size of 'ofpacts', in bytes. */
>
...
> @@ -2847,7 +2847,9 @@ ofproto_rule_change_cookie(struct ofproto *ofproto,
> struct rule *rule,
> if (new_cookie != rule->flow_cookie) {
> cookies_remove(ofproto, rule);
>
> + ovs_rwlock_wrlock(&rule->rwlock);
> rule->flow_cookie = new_cookie;
> + ovs_rwlock_unlock(&rule->rwlock);
>
Is this necessary on 64-bit systems?
> cookies_insert(ofproto, rule);
> }
>
Jarno
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