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classifier: Remove internal mutex.
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Almost all classifier users already exclude concurrent modifications,
or are single-threaded, hence the classifier internal mutex can be
removed.  Due to this change, ovs-router.c and tnl-ports.c need new
mutexes, which are added.

As noted by Ben in review, ovs_router_flush() should also free the
entries it removes from the classifier.  It now calls
ovsrcu_postpone() to that effect.

Suggested-by: Ben Pfaff <blp@nicira.com>
Signed-off-by: Jarno Rajahalme <jrajahalme@nicira.com>
Acked-by: Ben Pfaff <blp@nicira.com>
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Jarno Rajahalme committed Nov 14, 2014
1 parent de4ad4a commit fccd7c0
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Showing 6 changed files with 56 additions and 87 deletions.
14 changes: 7 additions & 7 deletions lib/classifier-private.h
View file
Expand Up @@ -27,11 +27,11 @@

/* A set of rules that all have the same fields wildcarded. */
struct cls_subtable {
struct cmap_node cmap_node OVS_GUARDED; /* Within struct classifier's
* 'subtables_map'. */
struct cmap_node cmap_node; /* Within classifier's 'subtables_map'. */

/* These fields are only used by writers. */
int max_priority OVS_GUARDED; /* Max priority of any rule in subtable. */
unsigned int max_count OVS_GUARDED; /* Count of max_priority rules. */
int max_priority; /* Max priority of any rule in subtable. */
unsigned int max_count; /* Count of max_priority rules. */

/* Accessed by iterators. */
struct rculist rules_list; /* Unordered. */
Expand Down Expand Up @@ -62,16 +62,16 @@ struct cls_partition {
struct cmap_node cmap_node; /* In struct classifier's 'partitions' map. */
ovs_be64 metadata; /* metadata value for this partition. */
tag_type tags; /* OR of each flow's cls_subtable tag. */
struct tag_tracker tracker OVS_GUARDED; /* Tracks the bits in 'tags'. */
struct tag_tracker tracker; /* Tracks the bits in 'tags'. */
};

/* Internal representation of a rule in a "struct cls_subtable". */
struct cls_match {
/* Accessed by everybody. */
struct rculist list OVS_GUARDED; /* Identical, lower-priority rules. */
struct rculist list; /* Identical, lower-priority rules. */

/* Accessed only by writers. */
struct cls_partition *partition OVS_GUARDED;
struct cls_partition *partition;

/* Accessed by readers interested in wildcarding. */
const int priority; /* Larger numbers are higher priorities. */
Expand Down
46 changes: 5 additions & 41 deletions lib/classifier.c
View file
Expand Up @@ -56,10 +56,8 @@ cls_match_alloc(struct cls_rule *rule)
static struct cls_subtable *find_subtable(const struct classifier *cls,
const struct minimask *);
static struct cls_subtable *insert_subtable(struct classifier *cls,
const struct minimask *)
OVS_REQUIRES(cls->mutex);
static void destroy_subtable(struct classifier *cls, struct cls_subtable *)
OVS_REQUIRES(cls->mutex);
const struct minimask *);
static void destroy_subtable(struct classifier *cls, struct cls_subtable *);

static const struct cls_match *find_match_wc(const struct cls_subtable *,
const struct flow *,
Expand Down Expand Up @@ -99,9 +97,7 @@ next_rule_in_list_protected(struct cls_match *rule)
return next->priority < rule->priority ? next : NULL;
}

/* Iterates RULE over HEAD and all of the cls_rules on HEAD->list.
* Classifier's mutex must be held while iterating, as the list is
* protoceted by it. */
/* Iterates RULE over HEAD and all of the cls_rules on HEAD->list. */
#define FOR_EACH_RULE_IN_LIST(RULE, HEAD) \
for ((RULE) = (HEAD); (RULE) != NULL; (RULE) = next_rule_in_list(RULE))
#define FOR_EACH_RULE_IN_LIST_PROTECTED(RULE, HEAD) \
Expand All @@ -111,8 +107,7 @@ next_rule_in_list_protected(struct cls_match *rule)
static unsigned int minimask_get_prefix_len(const struct minimask *,
const struct mf_field *);
static void trie_init(struct classifier *cls, int trie_idx,
const struct mf_field *)
OVS_REQUIRES(cls->mutex);
const struct mf_field *);
static unsigned int trie_lookup(const struct cls_trie *, const struct flow *,
union mf_value *plens);
static unsigned int trie_lookup_value(const rcu_trie_ptr *,
Expand All @@ -134,7 +129,6 @@ static bool mask_prefix_bits_set(const struct flow_wildcards *,

static inline void
cls_rule_init__(struct cls_rule *rule, unsigned int priority)
OVS_NO_THREAD_SAFETY_ANALYSIS
{
rculist_init(&rule->node);
rule->priority = priority;
Expand Down Expand Up @@ -181,7 +175,6 @@ cls_rule_clone(struct cls_rule *dst, const struct cls_rule *src)
* The caller must eventually destroy 'dst' with cls_rule_destroy(). */
void
cls_rule_move(struct cls_rule *dst, struct cls_rule *src)
OVS_NO_THREAD_SAFETY_ANALYSIS
{
ovs_assert(!src->cls_match); /* Must not be in a classifier. */
cls_rule_init__(dst, src->priority);
Expand All @@ -194,7 +187,6 @@ cls_rule_move(struct cls_rule *dst, struct cls_rule *src)
* ('rule' must not currently be in a classifier.) */
void
cls_rule_destroy(struct cls_rule *rule)
OVS_NO_THREAD_SAFETY_ANALYSIS
{
ovs_assert(!rule->cls_match); /* Must not be in a classifier. */

Expand Down Expand Up @@ -240,10 +232,7 @@ cls_rule_is_catchall(const struct cls_rule *rule)
* rules. */
void
classifier_init(struct classifier *cls, const uint8_t *flow_segments)
OVS_EXCLUDED(cls->mutex)
{
ovs_mutex_init(&cls->mutex);
ovs_mutex_lock(&cls->mutex);
cls->n_rules = 0;
cmap_init(&cls->subtables_map);
pvector_init(&cls->subtables);
Expand All @@ -259,22 +248,19 @@ classifier_init(struct classifier *cls, const uint8_t *flow_segments)
for (int i = 0; i < CLS_MAX_TRIES; i++) {
trie_init(cls, i, NULL);
}
ovs_mutex_unlock(&cls->mutex);
}

/* Destroys 'cls'. Rules within 'cls', if any, are not freed; this is the
* caller's responsibility.
* May only be called after all the readers have been terminated. */
void
classifier_destroy(struct classifier *cls)
OVS_EXCLUDED(cls->mutex)
{
if (cls) {
struct cls_partition *partition;
struct cls_subtable *subtable;
int i;

ovs_mutex_lock(&cls->mutex);
for (i = 0; i < cls->n_tries; i++) {
trie_destroy(&cls->tries[i].root);
}
Expand All @@ -290,8 +276,6 @@ classifier_destroy(struct classifier *cls)
cmap_destroy(&cls->partitions);

pvector_destroy(&cls->subtables);
ovs_mutex_unlock(&cls->mutex);
ovs_mutex_destroy(&cls->mutex);
}
}

Expand All @@ -300,14 +284,12 @@ bool
classifier_set_prefix_fields(struct classifier *cls,
const enum mf_field_id *trie_fields,
unsigned int n_fields)
OVS_EXCLUDED(cls->mutex)
{
const struct mf_field * new_fields[CLS_MAX_TRIES];
struct mf_bitmap fields = MF_BITMAP_INITIALIZER;
int i, n_tries = 0;
bool changed = false;

ovs_mutex_lock(&cls->mutex);
for (i = 0; i < n_fields && n_tries < CLS_MAX_TRIES; i++) {
const struct mf_field *field = mf_from_id(trie_fields[i]);
if (field->flow_be32ofs < 0 || field->n_bits % 32) {
Expand Down Expand Up @@ -370,17 +352,14 @@ classifier_set_prefix_fields(struct classifier *cls,
}

cls->n_tries = n_tries;
ovs_mutex_unlock(&cls->mutex);
return true;
}

ovs_mutex_unlock(&cls->mutex);
return false; /* No change. */
}

static void
trie_init(struct classifier *cls, int trie_idx, const struct mf_field *field)
OVS_REQUIRES(cls->mutex)
{
struct cls_trie *trie = &cls->tries[trie_idx];
struct cls_subtable *subtable;
Expand Down Expand Up @@ -422,7 +401,6 @@ classifier_is_empty(const struct classifier *cls)
/* Returns the number of rules in 'cls'. */
int
classifier_count(const struct classifier *cls)
OVS_NO_THREAD_SAFETY_ANALYSIS
{
/* n_rules is an int, so in the presence of concurrent writers this will
* return either the old or a new value. */
Expand Down Expand Up @@ -453,7 +431,6 @@ find_partition(const struct classifier *cls, ovs_be64 metadata, uint32_t hash)
static struct cls_partition *
create_partition(struct classifier *cls, struct cls_subtable *subtable,
ovs_be64 metadata)
OVS_REQUIRES(cls->mutex)
{
uint32_t hash = hash_metadata(metadata);
struct cls_partition *partition = find_partition(cls, metadata, hash);
Expand All @@ -480,7 +457,6 @@ subtable_replace_head_rule(struct classifier *cls OVS_UNUSED,
struct cls_subtable *subtable,
struct cls_match *head, struct cls_match *new,
uint32_t hash, uint32_t ihash[CLS_MAX_INDICES])
OVS_REQUIRES(cls->mutex)
{
/* Rule's data is already in the tries. */

Expand Down Expand Up @@ -510,7 +486,6 @@ subtable_replace_head_rule(struct classifier *cls OVS_UNUSED,
*/
const struct cls_rule *
classifier_replace(struct classifier *cls, struct cls_rule *rule)
OVS_EXCLUDED(cls->mutex)
{
struct cls_match *new = cls_match_alloc(rule);
struct cls_subtable *subtable;
Expand All @@ -522,7 +497,6 @@ classifier_replace(struct classifier *cls, struct cls_rule *rule)
uint32_t hash;
int i;

ovs_mutex_lock(&cls->mutex);
rule->cls_match = new;

subtable = find_subtable(cls, &rule->match.mask);
Expand Down Expand Up @@ -628,7 +602,6 @@ classifier_replace(struct classifier *cls, struct cls_rule *rule)

/* Return displaced rule. Caller is responsible for keeping it
* around until all threads quiesce. */
ovs_mutex_unlock(&cls->mutex);
return old;
}
} else {
Expand Down Expand Up @@ -659,7 +632,6 @@ classifier_replace(struct classifier *cls, struct cls_rule *rule)

/* Nothing was replaced. */
cls->n_rules++;
ovs_mutex_unlock(&cls->mutex);
return NULL;
}

Expand All @@ -686,7 +658,6 @@ classifier_insert(struct classifier *cls, struct cls_rule *rule)
*/
const struct cls_rule *
classifier_remove(struct classifier *cls, const struct cls_rule *rule)
OVS_EXCLUDED(cls->mutex)
{
struct cls_partition *partition;
struct cls_match *cls_match;
Expand All @@ -698,11 +669,9 @@ classifier_remove(struct classifier *cls, const struct cls_rule *rule)
uint8_t prev_be32ofs = 0;
size_t n_rules;

ovs_mutex_lock(&cls->mutex);
cls_match = rule->cls_match;
if (!cls_match) {
rule = NULL;
goto unlock; /* Already removed. */
return NULL;
}
/* Mark as removed. */
CONST_CAST(struct cls_rule *, rule)->cls_match = NULL;
Expand Down Expand Up @@ -799,8 +768,6 @@ classifier_remove(struct classifier *cls, const struct cls_rule *rule)
free:
ovsrcu_postpone(free, cls_match);
cls->n_rules--;
unlock:
ovs_mutex_unlock(&cls->mutex);

return rule;
}
Expand Down Expand Up @@ -1134,7 +1101,6 @@ find_subtable(const struct classifier *cls, const struct minimask *mask)
/* The new subtable will be visible to the readers only after this. */
static struct cls_subtable *
insert_subtable(struct classifier *cls, const struct minimask *mask)
OVS_REQUIRES(cls->mutex)
{
uint32_t hash = minimask_hash(mask, 0);
struct cls_subtable *subtable;
Expand Down Expand Up @@ -1204,7 +1170,6 @@ insert_subtable(struct classifier *cls, const struct minimask *mask)
/* RCU readers may still access the subtable before it is actually freed. */
static void
destroy_subtable(struct classifier *cls, struct cls_subtable *subtable)
OVS_REQUIRES(cls->mutex)
{
int i;

Expand Down Expand Up @@ -1605,7 +1570,6 @@ trie_node_rcu_realloc(const struct trie_node *node)
return new_node;
}

/* May only be called while holding the classifier mutex. */
static void
trie_destroy(rcu_trie_ptr *trie)
{
Expand Down
23 changes: 10 additions & 13 deletions lib/classifier.h
View file
Expand Up @@ -216,7 +216,6 @@
#include "cmap.h"
#include "match.h"
#include "meta-flow.h"
#include "ovs-thread.h"
#include "pvector.h"
#include "rculist.h"

Expand Down Expand Up @@ -244,8 +243,7 @@ enum {

/* A flow classifier. */
struct classifier {
struct ovs_mutex mutex;
int n_rules OVS_GUARDED; /* Total number of rules. */
int n_rules; /* Total number of rules. */
uint8_t n_flow_segments;
uint8_t flow_segments[CLS_MAX_INDICES]; /* Flow segment boundaries to use
* for staged lookup. */
Expand All @@ -260,7 +258,7 @@ struct classifier {
struct cls_rule {
struct rculist node; /* In struct cls_subtable 'rules_list'. */
int priority; /* Larger numbers are higher priorities. */
struct cls_match *cls_match OVS_GUARDED; /* NULL if not in a classifier. */
struct cls_match *cls_match; /* NULL if not in a classifier. */
struct minimatch match; /* Matching rule. */
};

Expand All @@ -270,42 +268,41 @@ void cls_rule_init_from_minimatch(struct cls_rule *, const struct minimatch *,
void cls_rule_clone(struct cls_rule *, const struct cls_rule *);
void cls_rule_move(struct cls_rule *dst, struct cls_rule *src);
void cls_rule_destroy(struct cls_rule *);

bool cls_rule_equal(const struct cls_rule *, const struct cls_rule *);
uint32_t cls_rule_hash(const struct cls_rule *, uint32_t basis);

void cls_rule_format(const struct cls_rule *, struct ds *);

bool cls_rule_is_catchall(const struct cls_rule *);

bool cls_rule_is_loose_match(const struct cls_rule *rule,
const struct minimatch *criteria);

/* Constructor/destructor. Must run single-threaded. */
void classifier_init(struct classifier *, const uint8_t *flow_segments);
void classifier_destroy(struct classifier *);

/* Modifiers. Caller MUST exclude concurrent calls from other threads. */
bool classifier_set_prefix_fields(struct classifier *,
const enum mf_field_id *trie_fields,
unsigned int n_trie_fields);

bool classifier_is_empty(const struct classifier *);
int classifier_count(const struct classifier *);
void classifier_insert(struct classifier *, struct cls_rule *);
const struct cls_rule *classifier_replace(struct classifier *,
struct cls_rule *);
const struct cls_rule *classifier_remove(struct classifier *,
const struct cls_rule *);

/* Lookups. These are RCU protected and may run concurrently with modifiers
* and each other. */
const struct cls_rule *classifier_lookup(const struct classifier *,
const struct flow *,
struct flow_wildcards *);
bool classifier_rule_overlaps(const struct classifier *,
const struct cls_rule *);

const struct cls_rule *classifier_find_rule_exactly(const struct classifier *,
const struct cls_rule *);

const struct cls_rule *classifier_find_match_exactly(const struct classifier *,
const struct match *,
int priority);
bool classifier_is_empty(const struct classifier *);
int classifier_count(const struct classifier *);

/* Iteration.
*
Expand Down

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