struct cls_match 'list' member was recently changed to an rculist.
This allows classifier_find_rule_exactly() to be made lockless.
Since subtable's 'max_priority' member would still require a lock, we
no longer check it before calling find_equal(). This adds a hash table
lookup in cases where the subtable may already be known to not contain
any rule of the target priority. If this is deemed a significant
change, we could change the 'max_priority' member to be an atomic
variable so that it could be safely accessed without a lock.
Signed-off-by: Jarno Rajahalme <jrajaha...@nicira.com>
---
lib/classifier.c | 15 ++++-----------
1 file changed, 4 insertions(+), 11 deletions(-)
diff --git a/lib/classifier.c b/lib/classifier.c
index 0c7d5c3..35d950c 100644
--- a/lib/classifier.c
+++ b/lib/classifier.c
@@ -755,33 +755,26 @@ classifier_lookup(const struct classifier *cls, const
struct flow *flow,
const struct cls_rule *
classifier_find_rule_exactly(const struct classifier *cls,
const struct cls_rule *target)
- OVS_EXCLUDED(cls->mutex)
{
const struct cls_match *head, *rule;
const struct cls_subtable *subtable;
- ovs_mutex_lock(&cls->mutex);
subtable = find_subtable(cls, &target->match.mask);
if (!subtable) {
- goto out;
- }
-
- /* Skip if there is no hope. */
- if (target->priority > subtable->max_priority) {
- goto out;
+ return NULL;
}
head = find_equal(subtable, &target->match.flow,
miniflow_hash_in_minimask(&target->match.flow,
&target->match.mask, 0));
+ if (!head) {
+ return NULL;
+ }
FOR_EACH_RULE_IN_LIST (rule, head) {
if (target->priority >= rule->priority) {
- ovs_mutex_unlock(&cls->mutex);
return target->priority == rule->priority ? rule->cls_rule : NULL;
}
}
-out:
- ovs_mutex_unlock(&cls->mutex);
return NULL;
}
--
1.7.10.4
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