#include "vlan.h"
#define TBL_MIN_BUCKETS 1024
+#define MASK_ARRAY_SIZE_MIN 16
#define REHASH_INTERVAL (10 * 60 * HZ)
+#define MC_HASH_SHIFT 8
+#define MC_HASH_ENTRIES (1u << MC_HASH_SHIFT)
+#define MC_HASH_SEGS ((sizeof(uint32_t) * 8) / MC_HASH_SHIFT)
+
static struct kmem_cache *flow_cache;
+struct kmem_cache *flow_stats_cache __read_mostly;
static u16 range_n_bytes(const struct sw_flow_key_range *range)
{
void ovs_flow_mask_key(struct sw_flow_key *dst, const struct sw_flow_key *src,
const struct sw_flow_mask *mask)
{
- const long *m = (long *)((u8 *)&mask->key + mask->range.start);
- const long *s = (long *)((u8 *)src + mask->range.start);
+ const long *m = (const long *)((const u8 *)&mask->key +
+ mask->range.start);
+ const long *s = (const long *)((const u8 *)src +
+ mask->range.start);
long *d = (long *)((u8 *)dst + mask->range.start);
int i;
*d++ = *s++ & *m++;
}
-struct sw_flow *ovs_flow_alloc(bool percpu_stats)
+struct sw_flow *ovs_flow_alloc(void)
{
struct sw_flow *flow;
- int cpu;
+ struct flow_stats *stats;
+ int node;
flow = kmem_cache_alloc(flow_cache, GFP_KERNEL);
if (!flow)
flow->sf_acts = NULL;
flow->mask = NULL;
+ flow->stats_last_writer = NUMA_NO_NODE;
- flow->stats.is_percpu = percpu_stats;
+ /* Initialize the default stat node. */
+ stats = kmem_cache_alloc_node(flow_stats_cache,
+ GFP_KERNEL | __GFP_ZERO, 0);
+ if (!stats)
+ goto err;
- if (!percpu_stats) {
- flow->stats.stat = kzalloc(sizeof(*flow->stats.stat), GFP_KERNEL);
- if (!flow->stats.stat)
- goto err;
+ spin_lock_init(&stats->lock);
- spin_lock_init(&flow->stats.stat->lock);
- } else {
- flow->stats.cpu_stats = alloc_percpu(struct flow_stats);
- if (!flow->stats.cpu_stats)
- goto err;
+ RCU_INIT_POINTER(flow->stats[0], stats);
- for_each_possible_cpu(cpu) {
- struct flow_stats *cpu_stats;
+ for_each_node(node)
+ if (node != 0)
+ RCU_INIT_POINTER(flow->stats[node], NULL);
- cpu_stats = per_cpu_ptr(flow->stats.cpu_stats, cpu);
- spin_lock_init(&cpu_stats->lock);
- }
- }
return flow;
err:
- kfree(flow);
+ kmem_cache_free(flow_cache, flow);
return ERR_PTR(-ENOMEM);
}
static void flow_free(struct sw_flow *flow)
{
- kfree((struct sf_flow_acts __force *)flow->sf_acts);
- if (flow->stats.is_percpu)
- free_percpu(flow->stats.cpu_stats);
- else
- kfree(flow->stats.stat);
+ int node;
+
+ kfree((struct sw_flow_actions __force *)flow->sf_acts);
+ for_each_node(node)
+ if (flow->stats[node])
+ kmem_cache_free(flow_stats_cache,
+ (struct flow_stats __force *)flow->stats[node]);
kmem_cache_free(flow_cache, flow);
}
kfree(mask);
}
-static void flow_mask_del_ref(struct sw_flow_mask *mask, bool deferred)
-{
- if (!mask)
- return;
-
- BUG_ON(!mask->ref_count);
- mask->ref_count--;
-
- if (!mask->ref_count) {
- list_del_rcu(&mask->list);
- if (deferred)
- call_rcu(&mask->rcu, rcu_free_sw_flow_mask_cb);
- else
- kfree(mask);
- }
-}
-
void ovs_flow_free(struct sw_flow *flow, bool deferred)
{
if (!flow)
return;
- flow_mask_del_ref(flow->mask, deferred);
-
if (deferred)
call_rcu(&flow->rcu, rcu_free_flow_callback);
else
flex_array_free(buckets);
}
+
static void __table_instance_destroy(struct table_instance *ti)
{
- int i;
-
- if (ti->keep_flows)
- goto skip_flows;
-
- for (i = 0; i < ti->n_buckets; i++) {
- struct sw_flow *flow;
- struct hlist_head *head = flex_array_get(ti->buckets, i);
- struct hlist_node *n;
- int ver = ti->node_ver;
-
- hlist_for_each_entry_safe(flow, n, head, hash_node[ver]) {
- hlist_del(&flow->hash_node[ver]);
- ovs_flow_free(flow, false);
- }
- }
-
-skip_flows:
free_buckets(ti->buckets);
kfree(ti);
}
return ti;
}
+static void mask_array_rcu_cb(struct rcu_head *rcu)
+{
+ struct mask_array *ma = container_of(rcu, struct mask_array, rcu);
+
+ kfree(ma);
+}
+
+static struct mask_array *tbl_mask_array_alloc(int size)
+{
+ struct mask_array *new;
+
+ new = kzalloc(sizeof(struct mask_array) +
+ sizeof(struct sw_flow_mask *) * size, GFP_KERNEL);
+ if (!new)
+ return NULL;
+
+ new->count = 0;
+ new->max = size;
+
+ return new;
+}
+
+static int tbl_mask_array_realloc(struct flow_table *tbl, int size)
+{
+ struct mask_array *old;
+ struct mask_array *new;
+
+ new = tbl_mask_array_alloc(size);
+ if (!new)
+ return -ENOMEM;
+
+ old = ovsl_dereference(tbl->mask_array);
+ if (old) {
+ int i;
+
+ for (i = 0; i < old->max; i++)
+ new->masks[i] = old->masks[i];
+
+ new->count = old->count;
+ }
+ rcu_assign_pointer(tbl->mask_array, new);
+
+ if (old)
+ call_rcu(&old->rcu, mask_array_rcu_cb);
+
+ return 0;
+}
+
+static void tbl_mask_array_delete_mask(struct mask_array *ma,
+ const struct sw_flow_mask *mask)
+{
+ int i = 0;
+
+ /* Delete a mask pointer from the valid section.
+ *
+ * Also move the last entry in its place, so there is no
+ * whole in the valid section.
+ *
+ * Notice the last entry still points to the original mask.
+ *
+ * <Note>: there is a small race window that may cause a mask
+ * to be missed in a search. Imaging a core is
+ * walking through the array, passing the index of deleting mask.
+ * But before reaching the last entry, it is overwritten,
+ * by another core that is adding a new mask, now the last entry
+ * will point to the new mask. In this case, the moved up last
+ * entry can be missed by the core walking the mask array.
+ *
+ * In case this missed mask would have led to successful
+ * lookup, Hitting the race window could cause a packet to miss
+ * kernel flow cache, and be sent to the user space.
+ * </Note>
+ */
+ for (i = 0; i < ma->count; i++)
+ if (mask == ovsl_dereference(ma->masks[i])) {
+ struct sw_flow_mask *last;
+
+ last = ovsl_dereference(ma->masks[ma->count - 1]);
+ rcu_assign_pointer(ma->masks[i], last);
+ ma->count--;
+ break;
+ }
+
+ /* Remove the deleted mask pointers from the invalid section. */
+ for (i = ma->count; i < ma->max; i++)
+ if (mask == ovsl_dereference(ma->masks[i]))
+ RCU_INIT_POINTER(ma->masks[i], NULL);
+}
+
int ovs_flow_tbl_init(struct flow_table *table)
{
struct table_instance *ti;
+ struct mask_array *ma;
- ti = table_instance_alloc(TBL_MIN_BUCKETS);
+ table->mask_cache = __alloc_percpu(sizeof(struct mask_cache_entry) *
+ MC_HASH_ENTRIES, __alignof__(struct mask_cache_entry));
+ if (!table->mask_cache)
+ return -ENOMEM;
+ ma = tbl_mask_array_alloc(MASK_ARRAY_SIZE_MIN);
+ if (!ma)
+ goto free_mask_cache;
+
+ ti = table_instance_alloc(TBL_MIN_BUCKETS);
if (!ti)
- return -ENOMEM;
+ goto free_mask_array;
rcu_assign_pointer(table->ti, ti);
- INIT_LIST_HEAD(&table->mask_list);
+ rcu_assign_pointer(table->mask_array, ma);
table->last_rehash = jiffies;
table->count = 0;
return 0;
+
+free_mask_array:
+ kfree((struct mask_array __force *)table->mask_array);
+free_mask_cache:
+ free_percpu(table->mask_cache);
+ return -ENOMEM;
}
static void flow_tbl_destroy_rcu_cb(struct rcu_head *rcu)
static void table_instance_destroy(struct table_instance *ti, bool deferred)
{
+ int i;
+
if (!ti)
return;
+ if (ti->keep_flows)
+ goto skip_flows;
+
+ for (i = 0; i < ti->n_buckets; i++) {
+ struct sw_flow *flow;
+ struct hlist_head *head = flex_array_get(ti->buckets, i);
+ struct hlist_node *n;
+ int ver = ti->node_ver;
+
+ hlist_for_each_entry_safe(flow, n, head, hash_node[ver]) {
+ hlist_del_rcu(&flow->hash_node[ver]);
+ ovs_flow_free(flow, deferred);
+ }
+ }
+
+skip_flows:
if (deferred)
call_rcu(&ti->rcu, flow_tbl_destroy_rcu_cb);
else
__table_instance_destroy(ti);
}
+/* No need for locking this function is called from RCU callback or
+ * error path. */
void ovs_flow_tbl_destroy(struct flow_table *table)
{
- struct table_instance *ti = ovsl_dereference(table->ti);
+ struct table_instance *ti = (struct table_instance __force *)table->ti;
+ free_percpu(table->mask_cache);
+ kfree((struct mask_array __force *)table->mask_array);
table_instance_destroy(ti, false);
}
static u32 flow_hash(const struct sw_flow_key *key, int key_start,
int key_end)
{
- u32 *hash_key = (u32 *)((u8 *)key + key_start);
+ const u32 *hash_key = (const u32 *)((const u8 *)key + key_start);
int hash_u32s = (key_end - key_start) >> 2;
/* Make sure number of hash bytes are multiple of u32. */
const struct sw_flow_key *key2,
int key_start, int key_end)
{
- const long *cp1 = (long *)((u8 *)key1 + key_start);
- const long *cp2 = (long *)((u8 *)key2 + key_start);
+ const long *cp1 = (const long *)((const u8 *)key1 + key_start);
+ const long *cp2 = (const long *)((const u8 *)key2 + key_start);
long diffs = 0;
int i;
static struct sw_flow *masked_flow_lookup(struct table_instance *ti,
const struct sw_flow_key *unmasked,
- struct sw_flow_mask *mask)
+ struct sw_flow_mask *mask,
+ u32 *n_mask_hit)
{
struct sw_flow *flow;
struct hlist_head *head;
ovs_flow_mask_key(&masked_key, unmasked, mask);
hash = flow_hash(&masked_key, key_start, key_end);
head = find_bucket(ti, hash);
+ (*n_mask_hit)++;
hlist_for_each_entry_rcu(flow, head, hash_node[ti->node_ver]) {
if (flow->mask == mask && flow->hash == hash &&
flow_cmp_masked_key(flow, &masked_key,
return NULL;
}
-struct sw_flow *ovs_flow_tbl_lookup_stats(struct flow_table *tbl,
- const struct sw_flow_key *key,
- u32 *n_mask_hit)
+static struct sw_flow *flow_lookup(struct flow_table *tbl,
+ struct table_instance *ti,
+ struct mask_array *ma,
+ const struct sw_flow_key *key,
+ u32 *n_mask_hit,
+ u32 *index)
{
- struct table_instance *ti = rcu_dereference_ovsl(tbl->ti);
- struct sw_flow_mask *mask;
struct sw_flow *flow;
+ int i;
- *n_mask_hit = 0;
- list_for_each_entry_rcu(mask, &tbl->mask_list, list) {
- (*n_mask_hit)++;
- flow = masked_flow_lookup(ti, key, mask);
- if (flow) /* Found */
+ for (i = 0; i < ma->max; i++) {
+ struct sw_flow_mask *mask;
+
+ mask = rcu_dereference_ovsl(ma->masks[i]);
+ if (!mask)
+ break;
+
+ flow = masked_flow_lookup(ti, key, mask, n_mask_hit);
+ if (flow) { /* Found */
+ *index = i;
return flow;
+ }
}
+
return NULL;
}
+/*
+ * mask_cache maps flow to probable mask. This cache is not tightly
+ * coupled cache, It means updates to mask list can result in inconsistent
+ * cache entry in mask cache.
+ * This is per cpu cache and is divided in MC_HASH_SEGS segments.
+ * In case of a hash collision the entry is hashed in next segment.
+ * */
+struct sw_flow *ovs_flow_tbl_lookup_stats(struct flow_table *tbl,
+ const struct sw_flow_key *key,
+ u32 skb_hash,
+ u32 *n_mask_hit)
+{
+ struct mask_array *ma = rcu_dereference(tbl->mask_array);
+ struct table_instance *ti = rcu_dereference(tbl->ti);
+ struct mask_cache_entry *entries, *ce;
+ struct sw_flow *flow;
+ u32 hash = skb_hash;
+ int seg;
+
+ *n_mask_hit = 0;
+ if (unlikely(!skb_hash)) {
+ u32 __always_unused mask_index;
+
+ return flow_lookup(tbl, ti, ma, key, n_mask_hit, &mask_index);
+ }
+
+ ce = NULL;
+ entries = this_cpu_ptr(tbl->mask_cache);
+
+ /* Find the cache entry 'ce' to operate on. */
+ for (seg = 0; seg < MC_HASH_SEGS; seg++) {
+ int index = hash & (MC_HASH_ENTRIES - 1);
+ struct mask_cache_entry *e;
+
+ e = &entries[index];
+ if (e->skb_hash == skb_hash) {
+ struct sw_flow_mask *cache;
+ int i = e->mask_index;
+
+ if (likely(i < ma->max)) {
+ cache = rcu_dereference(ma->masks[i]);
+ if (cache) {
+ flow = masked_flow_lookup(ti, key,
+ cache, n_mask_hit);
+ if (flow)
+ return flow;
+ }
+ }
+
+ /* Cache miss. This is the best cache
+ * replacement candidate. */
+ e->skb_hash = 0;
+ ce = e;
+ break;
+ }
+
+ if (!ce || e->skb_hash < ce->skb_hash)
+ ce = e; /* A better replacement cache candidate. */
+
+ hash >>= MC_HASH_SHIFT;
+ }
+
+ /* Cache miss, do full lookup. */
+ flow = flow_lookup(tbl, ti, ma, key, n_mask_hit, &ce->mask_index);
+ if (flow)
+ ce->skb_hash = skb_hash;
+
+ return flow;
+}
+
struct sw_flow *ovs_flow_tbl_lookup(struct flow_table *tbl,
const struct sw_flow_key *key)
{
+ struct table_instance *ti = rcu_dereference_ovsl(tbl->ti);
+ struct mask_array *ma = rcu_dereference_ovsl(tbl->mask_array);
u32 __always_unused n_mask_hit;
+ u32 __always_unused index;
- return ovs_flow_tbl_lookup_stats(tbl, key, &n_mask_hit);
+ return flow_lookup(tbl, ti, ma, key, &n_mask_hit, &index);
}
-int ovs_flow_tbl_num_masks(const struct flow_table *table)
+struct sw_flow *ovs_flow_tbl_lookup_exact(struct flow_table *tbl,
+ struct sw_flow_match *match)
{
- struct sw_flow_mask *mask;
- int num = 0;
+ struct table_instance *ti = rcu_dereference_ovsl(tbl->ti);
+ struct mask_array *ma = rcu_dereference_ovsl(tbl->mask_array);
+ struct sw_flow *flow;
+ u32 __always_unused n_mask_hit;
+ int i;
+
+ /* Always called under ovs-mutex. */
+ for (i = 0; i < ma->count; i++) {
+ struct sw_flow_mask *mask;
+
+ mask = ovsl_dereference(ma->masks[i]);
+ if (mask) {
+ flow = masked_flow_lookup(ti, match->key, mask, &n_mask_hit);
+ if (flow && ovs_flow_cmp_unmasked_key(flow, match)) { /* Found */
+ return flow;
+ }
+ }
+ }
+ return NULL;
+}
- list_for_each_entry(mask, &table->mask_list, list)
- num++;
+int ovs_flow_tbl_num_masks(const struct flow_table *table)
+{
+ struct mask_array *ma;
- return num;
+ ma = rcu_dereference_ovsl(table->mask_array);
+ return ma->count;
}
static struct table_instance *table_instance_expand(struct table_instance *ti)
return table_instance_rehash(ti, ti->n_buckets * 2);
}
+/* Remove 'mask' from the mask list, if it is not needed any more. */
+static void flow_mask_remove(struct flow_table *tbl, struct sw_flow_mask *mask)
+{
+ if (mask) {
+ /* ovs-lock is required to protect mask-refcount and
+ * mask list.
+ */
+ ASSERT_OVSL();
+ BUG_ON(!mask->ref_count);
+ mask->ref_count--;
+
+ if (!mask->ref_count) {
+ struct mask_array *ma;
+
+ ma = ovsl_dereference(tbl->mask_array);
+ /* Shrink the mask array if necessary. */
+ if (ma->max > MASK_ARRAY_SIZE_MIN * 2
+ && ma->count <= ma->max / 4) {
+
+ tbl_mask_array_realloc(tbl, ma->max / 2);
+ ma = ovsl_dereference(tbl->mask_array);
+ }
+
+ tbl_mask_array_delete_mask(ma, mask);
+ call_rcu(&mask->rcu, rcu_free_sw_flow_mask_cb);
+ }
+ }
+}
+
+/* Must be called with OVS mutex held. */
void ovs_flow_tbl_remove(struct flow_table *table, struct sw_flow *flow)
{
struct table_instance *ti = ovsl_dereference(table->ti);
BUG_ON(table->count == 0);
hlist_del_rcu(&flow->hash_node[ti->node_ver]);
table->count--;
+
+ /* RCU delete the mask. 'flow->mask' is not NULLed, as it should be
+ * accessible as long as the RCU read lock is held. */
+ flow_mask_remove(table, flow->mask);
}
static struct sw_flow_mask *mask_alloc(void)
mask = kmalloc(sizeof(*mask), GFP_KERNEL);
if (mask)
- mask->ref_count = 0;
+ mask->ref_count = 1;
return mask;
}
-static void mask_add_ref(struct sw_flow_mask *mask)
-{
- mask->ref_count++;
-}
-
static bool mask_equal(const struct sw_flow_mask *a,
const struct sw_flow_mask *b)
{
- u8 *a_ = (u8 *)&a->key + a->range.start;
- u8 *b_ = (u8 *)&b->key + b->range.start;
+ const u8 *a_ = (const u8 *)&a->key + a->range.start;
+ const u8 *b_ = (const u8 *)&b->key + b->range.start;
return (a->range.end == b->range.end)
&& (a->range.start == b->range.start)
static struct sw_flow_mask *flow_mask_find(const struct flow_table *tbl,
const struct sw_flow_mask *mask)
{
- struct list_head *ml;
+ struct mask_array *ma;
+ int i;
+
+ ma = ovsl_dereference(tbl->mask_array);
+ for (i = 0; i < ma->count; i++) {
+ struct sw_flow_mask *t;
- list_for_each(ml, &tbl->mask_list) {
- struct sw_flow_mask *m;
- m = container_of(ml, struct sw_flow_mask, list);
- if (mask_equal(mask, m))
- return m;
+ t = ovsl_dereference(ma->masks[i]);
+ if (t && mask_equal(mask, t))
+ return t;
}
return NULL;
struct sw_flow_mask *new)
{
struct sw_flow_mask *mask;
+
mask = flow_mask_find(tbl, new);
if (!mask) {
+ struct mask_array *ma;
+
/* Allocate a new mask if none exsits. */
mask = mask_alloc();
if (!mask)
return -ENOMEM;
+
mask->key = new->key;
mask->range = new->range;
- list_add_rcu(&mask->list, &tbl->mask_list);
+
+ /* Add mask to mask-list. */
+ ma = ovsl_dereference(tbl->mask_array);
+ if (ma->count >= ma->max) {
+ int err;
+
+ err = tbl_mask_array_realloc(tbl, ma->max +
+ MASK_ARRAY_SIZE_MIN);
+ if (err) {
+ kfree(mask);
+ return err;
+ }
+ ma = ovsl_dereference(tbl->mask_array);
+ }
+
+ rcu_assign_pointer(ma->masks[ma->count], mask);
+ ma->count++;
+ } else {
+ BUG_ON(!mask->ref_count);
+ mask->ref_count++;
}
- mask_add_ref(mask);
flow->mask = mask;
return 0;
}
+/* Must be called with OVS mutex held. */
int ovs_flow_tbl_insert(struct flow_table *table, struct sw_flow *flow,
struct sw_flow_mask *mask)
{
BUILD_BUG_ON(__alignof__(struct sw_flow_key) % __alignof__(long));
BUILD_BUG_ON(sizeof(struct sw_flow_key) % sizeof(long));
- flow_cache = kmem_cache_create("sw_flow", sizeof(struct sw_flow), 0,
- 0, NULL);
+ flow_cache = kmem_cache_create("sw_flow", sizeof(struct sw_flow)
+ + (num_possible_nodes()
+ * sizeof(struct flow_stats *)),
+ 0, 0, NULL);
if (flow_cache == NULL)
return -ENOMEM;
+ flow_stats_cache
+ = kmem_cache_create("sw_flow_stats", sizeof(struct flow_stats),
+ 0, SLAB_HWCACHE_ALIGN, NULL);
+ if (flow_stats_cache == NULL) {
+ kmem_cache_destroy(flow_cache);
+ flow_cache = NULL;
+ return -ENOMEM;
+ }
+
return 0;
}
/* Uninitializes the flow module. */
void ovs_flow_exit(void)
{
+ kmem_cache_destroy(flow_stats_cache);
kmem_cache_destroy(flow_cache);
}