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-rw-r--r--net/openvswitch/flow_table.c412
1 files changed, 334 insertions, 78 deletions
diff --git a/net/openvswitch/flow_table.c b/net/openvswitch/flow_table.c
index fd8a01ca7a2d..d4a2db0b2299 100644
--- a/net/openvswitch/flow_table.c
+++ b/net/openvswitch/flow_table.c
@@ -29,6 +29,7 @@
#include <linux/icmp.h>
#include <linux/icmpv6.h>
#include <linux/rculist.h>
+#include <linux/sort.h>
#include <net/ip.h>
#include <net/ipv6.h>
#include <net/ndisc.h>
@@ -37,8 +38,8 @@
#define MASK_ARRAY_SIZE_MIN 16
#define REHASH_INTERVAL (10 * 60 * HZ)
+#define MC_DEFAULT_HASH_ENTRIES 256
#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;
@@ -110,12 +111,16 @@ static void flow_free(struct sw_flow *flow)
if (ovs_identifier_is_key(&flow->id))
kfree(flow->id.unmasked_key);
if (flow->sf_acts)
- ovs_nla_free_flow_actions((struct sw_flow_actions __force *)flow->sf_acts);
+ ovs_nla_free_flow_actions((struct sw_flow_actions __force *)
+ flow->sf_acts);
/* We open code this to make sure cpu 0 is always considered */
- for (cpu = 0; cpu < nr_cpu_ids; cpu = cpumask_next(cpu, &flow->cpu_used_mask))
+ for (cpu = 0; cpu < nr_cpu_ids;
+ cpu = cpumask_next(cpu, &flow->cpu_used_mask)) {
if (flow->stats[cpu])
kmem_cache_free(flow_stats_cache,
(struct sw_flow_stats __force *)flow->stats[cpu]);
+ }
+
kmem_cache_free(flow_cache, flow);
}
@@ -163,22 +168,76 @@ static struct table_instance *table_instance_alloc(int new_size)
ti->n_buckets = new_size;
ti->node_ver = 0;
- ti->keep_flows = false;
get_random_bytes(&ti->hash_seed, sizeof(u32));
return ti;
}
+static void __mask_array_destroy(struct mask_array *ma)
+{
+ free_percpu(ma->masks_usage_stats);
+ kfree(ma);
+}
+
+static void mask_array_rcu_cb(struct rcu_head *rcu)
+{
+ struct mask_array *ma = container_of(rcu, struct mask_array, rcu);
+
+ __mask_array_destroy(ma);
+}
+
+static void tbl_mask_array_reset_counters(struct mask_array *ma)
+{
+ int i, cpu;
+
+ /* As the per CPU counters are not atomic we can not go ahead and
+ * reset them from another CPU. To be able to still have an approximate
+ * zero based counter we store the value at reset, and subtract it
+ * later when processing.
+ */
+ for (i = 0; i < ma->max; i++) {
+ ma->masks_usage_zero_cntr[i] = 0;
+
+ for_each_possible_cpu(cpu) {
+ struct mask_array_stats *stats;
+ unsigned int start;
+ u64 counter;
+
+ stats = per_cpu_ptr(ma->masks_usage_stats, cpu);
+ do {
+ start = u64_stats_fetch_begin_irq(&stats->syncp);
+ counter = stats->usage_cntrs[i];
+ } while (u64_stats_fetch_retry_irq(&stats->syncp, start));
+
+ ma->masks_usage_zero_cntr[i] += counter;
+ }
+ }
+}
+
static struct mask_array *tbl_mask_array_alloc(int size)
{
struct mask_array *new;
size = max(MASK_ARRAY_SIZE_MIN, size);
new = kzalloc(sizeof(struct mask_array) +
- sizeof(struct sw_flow_mask *) * size, GFP_KERNEL);
+ sizeof(struct sw_flow_mask *) * size +
+ sizeof(u64) * size, GFP_KERNEL);
if (!new)
return NULL;
+ new->masks_usage_zero_cntr = (u64 *)((u8 *)new +
+ sizeof(struct mask_array) +
+ sizeof(struct sw_flow_mask *) *
+ size);
+
+ new->masks_usage_stats = __alloc_percpu(sizeof(struct mask_array_stats) +
+ sizeof(u64) * size,
+ __alignof__(u64));
+ if (!new->masks_usage_stats) {
+ kfree(new);
+ return NULL;
+ }
+
new->count = 0;
new->max = size;
@@ -202,10 +261,10 @@ static int tbl_mask_array_realloc(struct flow_table *tbl, int size)
if (ovsl_dereference(old->masks[i]))
new->masks[new->count++] = old->masks[i];
}
+ call_rcu(&old->rcu, mask_array_rcu_cb);
}
rcu_assign_pointer(tbl->mask_array, new);
- kfree_rcu(old, rcu);
return 0;
}
@@ -218,17 +277,22 @@ static int tbl_mask_array_add_mask(struct flow_table *tbl,
if (ma_count >= ma->max) {
err = tbl_mask_array_realloc(tbl, ma->max +
- MASK_ARRAY_SIZE_MIN);
+ MASK_ARRAY_SIZE_MIN);
if (err)
return err;
ma = ovsl_dereference(tbl->mask_array);
+ } else {
+ /* On every add or delete we need to reset the counters so
+ * every new mask gets a fair chance of being prioritized.
+ */
+ tbl_mask_array_reset_counters(ma);
}
BUG_ON(ovsl_dereference(ma->masks[ma_count]));
rcu_assign_pointer(ma->masks[ma_count], new);
- WRITE_ONCE(ma->count, ma_count +1);
+ WRITE_ONCE(ma->count, ma_count + 1);
return 0;
}
@@ -249,10 +313,10 @@ static void tbl_mask_array_del_mask(struct flow_table *tbl,
return;
found:
- WRITE_ONCE(ma->count, ma_count -1);
+ WRITE_ONCE(ma->count, ma_count - 1);
- rcu_assign_pointer(ma->masks[i], ma->masks[ma_count -1]);
- RCU_INIT_POINTER(ma->masks[ma_count -1], NULL);
+ rcu_assign_pointer(ma->masks[i], ma->masks[ma_count - 1]);
+ RCU_INIT_POINTER(ma->masks[ma_count - 1], NULL);
kfree_rcu(mask, rcu);
@@ -260,6 +324,9 @@ found:
if (ma->max >= (MASK_ARRAY_SIZE_MIN * 2) &&
ma_count <= (ma->max / 3))
tbl_mask_array_realloc(tbl, ma->max / 2);
+ else
+ tbl_mask_array_reset_counters(ma);
+
}
/* Remove 'mask' from the mask list, if it is not needed any more. */
@@ -278,15 +345,79 @@ static void flow_mask_remove(struct flow_table *tbl, struct sw_flow_mask *mask)
}
}
+static void __mask_cache_destroy(struct mask_cache *mc)
+{
+ free_percpu(mc->mask_cache);
+ kfree(mc);
+}
+
+static void mask_cache_rcu_cb(struct rcu_head *rcu)
+{
+ struct mask_cache *mc = container_of(rcu, struct mask_cache, rcu);
+
+ __mask_cache_destroy(mc);
+}
+
+static struct mask_cache *tbl_mask_cache_alloc(u32 size)
+{
+ struct mask_cache_entry __percpu *cache = NULL;
+ struct mask_cache *new;
+
+ /* Only allow size to be 0, or a power of 2, and does not exceed
+ * percpu allocation size.
+ */
+ if ((!is_power_of_2(size) && size != 0) ||
+ (size * sizeof(struct mask_cache_entry)) > PCPU_MIN_UNIT_SIZE)
+ return NULL;
+
+ new = kzalloc(sizeof(*new), GFP_KERNEL);
+ if (!new)
+ return NULL;
+
+ new->cache_size = size;
+ if (new->cache_size > 0) {
+ cache = __alloc_percpu(array_size(sizeof(struct mask_cache_entry),
+ new->cache_size),
+ __alignof__(struct mask_cache_entry));
+ if (!cache) {
+ kfree(new);
+ return NULL;
+ }
+ }
+
+ new->mask_cache = cache;
+ return new;
+}
+int ovs_flow_tbl_masks_cache_resize(struct flow_table *table, u32 size)
+{
+ struct mask_cache *mc = rcu_dereference_ovsl(table->mask_cache);
+ struct mask_cache *new;
+
+ if (size == mc->cache_size)
+ return 0;
+
+ if ((!is_power_of_2(size) && size != 0) ||
+ (size * sizeof(struct mask_cache_entry)) > PCPU_MIN_UNIT_SIZE)
+ return -EINVAL;
+
+ new = tbl_mask_cache_alloc(size);
+ if (!new)
+ return -ENOMEM;
+
+ rcu_assign_pointer(table->mask_cache, new);
+ call_rcu(&mc->rcu, mask_cache_rcu_cb);
+
+ return 0;
+}
+
int ovs_flow_tbl_init(struct flow_table *table)
{
struct table_instance *ti, *ufid_ti;
+ struct mask_cache *mc;
struct mask_array *ma;
- table->mask_cache = __alloc_percpu(sizeof(struct mask_cache_entry) *
- MC_HASH_ENTRIES,
- __alignof__(struct mask_cache_entry));
- if (!table->mask_cache)
+ mc = tbl_mask_cache_alloc(MC_DEFAULT_HASH_ENTRIES);
+ if (!mc)
return -ENOMEM;
ma = tbl_mask_array_alloc(MASK_ARRAY_SIZE_MIN);
@@ -304,6 +435,7 @@ int ovs_flow_tbl_init(struct flow_table *table)
rcu_assign_pointer(table->ti, ti);
rcu_assign_pointer(table->ufid_ti, ufid_ti);
rcu_assign_pointer(table->mask_array, ma);
+ rcu_assign_pointer(table->mask_cache, mc);
table->last_rehash = jiffies;
table->count = 0;
table->ufid_count = 0;
@@ -312,77 +444,71 @@ int ovs_flow_tbl_init(struct flow_table *table)
free_ti:
__table_instance_destroy(ti);
free_mask_array:
- kfree(ma);
+ __mask_array_destroy(ma);
free_mask_cache:
- free_percpu(table->mask_cache);
+ __mask_cache_destroy(mc);
return -ENOMEM;
}
static void flow_tbl_destroy_rcu_cb(struct rcu_head *rcu)
{
- struct table_instance *ti = container_of(rcu, struct table_instance, rcu);
+ struct table_instance *ti;
+ ti = container_of(rcu, struct table_instance, rcu);
__table_instance_destroy(ti);
}
static void table_instance_flow_free(struct flow_table *table,
- struct table_instance *ti,
- struct table_instance *ufid_ti,
- struct sw_flow *flow,
- bool count)
+ struct table_instance *ti,
+ struct table_instance *ufid_ti,
+ struct sw_flow *flow)
{
hlist_del_rcu(&flow->flow_table.node[ti->node_ver]);
- if (count)
- table->count--;
+ table->count--;
if (ovs_identifier_is_ufid(&flow->id)) {
hlist_del_rcu(&flow->ufid_table.node[ufid_ti->node_ver]);
-
- if (count)
- table->ufid_count--;
+ table->ufid_count--;
}
flow_mask_remove(table, flow->mask);
}
-static void table_instance_destroy(struct flow_table *table,
- struct table_instance *ti,
- struct table_instance *ufid_ti,
- bool deferred)
+/* Must be called with OVS mutex held. */
+void table_instance_flow_flush(struct flow_table *table,
+ struct table_instance *ti,
+ struct table_instance *ufid_ti)
{
int i;
- if (!ti)
- return;
-
- BUG_ON(!ufid_ti);
- if (ti->keep_flows)
- goto skip_flows;
-
for (i = 0; i < ti->n_buckets; i++) {
- struct sw_flow *flow;
struct hlist_head *head = &ti->buckets[i];
struct hlist_node *n;
+ struct sw_flow *flow;
hlist_for_each_entry_safe(flow, n, head,
flow_table.node[ti->node_ver]) {
table_instance_flow_free(table, ti, ufid_ti,
- flow, false);
- ovs_flow_free(flow, deferred);
+ flow);
+ ovs_flow_free(flow, true);
}
}
-skip_flows:
- if (deferred) {
- call_rcu(&ti->rcu, flow_tbl_destroy_rcu_cb);
- call_rcu(&ufid_ti->rcu, flow_tbl_destroy_rcu_cb);
- } else {
- __table_instance_destroy(ti);
- __table_instance_destroy(ufid_ti);
+ if (WARN_ON(table->count != 0 ||
+ table->ufid_count != 0)) {
+ table->count = 0;
+ table->ufid_count = 0;
}
}
+static void table_instance_destroy(struct table_instance *ti,
+ struct table_instance *ufid_ti)
+{
+ call_rcu(&ti->rcu, flow_tbl_destroy_rcu_cb);
+ call_rcu(&ufid_ti->rcu, flow_tbl_destroy_rcu_cb);
+}
+
/* No need for locking this function is called from RCU callback or
* error path.
*/
@@ -390,10 +516,12 @@ void ovs_flow_tbl_destroy(struct flow_table *table)
{
struct table_instance *ti = rcu_dereference_raw(table->ti);
struct table_instance *ufid_ti = rcu_dereference_raw(table->ufid_ti);
+ struct mask_cache *mc = rcu_dereference_raw(table->mask_cache);
+ struct mask_array *ma = rcu_dereference_raw(table->mask_array);
- free_percpu(table->mask_cache);
- kfree_rcu(rcu_dereference_raw(table->mask_array), rcu);
- table_instance_destroy(table, ti, ufid_ti, false);
+ call_rcu(&mc->rcu, mask_cache_rcu_cb);
+ call_rcu(&ma->rcu, mask_array_rcu_cb);
+ table_instance_destroy(ti, ufid_ti);
}
struct sw_flow *ovs_flow_tbl_dump_next(struct table_instance *ti,
@@ -462,16 +590,16 @@ static void flow_table_copy_flows(struct table_instance *old,
struct hlist_head *head = &old->buckets[i];
if (ufid)
- hlist_for_each_entry(flow, head,
- ufid_table.node[old_ver])
+ hlist_for_each_entry_rcu(flow, head,
+ ufid_table.node[old_ver],
+ lockdep_ovsl_is_held())
ufid_table_instance_insert(new, flow);
else
- hlist_for_each_entry(flow, head,
- flow_table.node[old_ver])
+ hlist_for_each_entry_rcu(flow, head,
+ flow_table.node[old_ver],
+ lockdep_ovsl_is_held())
table_instance_insert(new, flow);
}
-
- old->keep_flows = true;
}
static struct table_instance *table_instance_rehash(struct table_instance *ti,
@@ -506,10 +634,9 @@ int ovs_flow_tbl_flush(struct flow_table *flow_table)
rcu_assign_pointer(flow_table->ti, new_ti);
rcu_assign_pointer(flow_table->ufid_ti, new_ufid_ti);
flow_table->last_rehash = jiffies;
- flow_table->count = 0;
- flow_table->ufid_count = 0;
- table_instance_destroy(flow_table, old_ti, old_ufid_ti, true);
+ table_instance_flow_flush(flow_table, old_ti, old_ufid_ti);
+ table_instance_destroy(old_ti, old_ufid_ti);
return 0;
err_free_ti:
@@ -534,7 +661,7 @@ static int flow_key_start(const struct sw_flow_key *key)
return 0;
else
return rounddown(offsetof(struct sw_flow_key, phy),
- sizeof(long));
+ sizeof(long));
}
static bool cmp_key(const struct sw_flow_key *key1,
@@ -543,13 +670,13 @@ static bool cmp_key(const struct sw_flow_key *key1,
{
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;
- for (i = key_start; i < key_end; i += sizeof(long))
- diffs |= *cp1++ ^ *cp2++;
+ for (i = key_start; i < key_end; i += sizeof(long))
+ if (*cp1++ ^ *cp2++)
+ return false;
- return diffs == 0;
+ return true;
}
static bool flow_cmp_masked_key(const struct sw_flow *flow,
@@ -586,7 +713,7 @@ static struct sw_flow *masked_flow_lookup(struct table_instance *ti,
(*n_mask_hit)++;
hlist_for_each_entry_rcu(flow, head, flow_table.node[ti->node_ver],
- lockdep_ovsl_is_held()) {
+ lockdep_ovsl_is_held()) {
if (flow->mask == mask && flow->flow_table.hash == hash &&
flow_cmp_masked_key(flow, &masked_key, &mask->range))
return flow;
@@ -596,14 +723,18 @@ static struct sw_flow *masked_flow_lookup(struct table_instance *ti,
/* Flow lookup does full lookup on flow table. It starts with
* mask from index passed in *index.
+ * This function MUST be called with BH disabled due to the use
+ * of CPU specific variables.
*/
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 *n_cache_hit,
u32 *index)
{
+ struct mask_array_stats *stats = this_cpu_ptr(ma->masks_usage_stats);
struct sw_flow *flow;
struct sw_flow_mask *mask;
int i;
@@ -612,8 +743,13 @@ static struct sw_flow *flow_lookup(struct flow_table *tbl,
mask = rcu_dereference_ovsl(ma->masks[*index]);
if (mask) {
flow = masked_flow_lookup(ti, key, mask, n_mask_hit);
- if (flow)
+ if (flow) {
+ u64_stats_update_begin(&stats->syncp);
+ stats->usage_cntrs[*index]++;
+ u64_stats_update_end(&stats->syncp);
+ (*n_cache_hit)++;
return flow;
+ }
}
}
@@ -629,6 +765,9 @@ static struct sw_flow *flow_lookup(struct flow_table *tbl,
flow = masked_flow_lookup(ti, key, mask, n_mask_hit);
if (flow) { /* Found */
*index = i;
+ u64_stats_update_begin(&stats->syncp);
+ stats->usage_cntrs[*index]++;
+ u64_stats_update_end(&stats->syncp);
return flow;
}
}
@@ -646,8 +785,10 @@ static struct sw_flow *flow_lookup(struct flow_table *tbl,
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)
+ u32 *n_mask_hit,
+ u32 *n_cache_hit)
{
+ struct mask_cache *mc = rcu_dereference(tbl->mask_cache);
struct mask_array *ma = rcu_dereference(tbl->mask_array);
struct table_instance *ti = rcu_dereference(tbl->ti);
struct mask_cache_entry *entries, *ce;
@@ -656,10 +797,13 @@ struct sw_flow *ovs_flow_tbl_lookup_stats(struct flow_table *tbl,
int seg;
*n_mask_hit = 0;
- if (unlikely(!skb_hash)) {
+ *n_cache_hit = 0;
+ if (unlikely(!skb_hash || mc->cache_size == 0)) {
u32 mask_index = 0;
+ u32 cache = 0;
- return flow_lookup(tbl, ti, ma, key, n_mask_hit, &mask_index);
+ return flow_lookup(tbl, ti, ma, key, n_mask_hit, &cache,
+ &mask_index);
}
/* Pre and post recirulation flows usually have the same skb_hash
@@ -670,17 +814,17 @@ struct sw_flow *ovs_flow_tbl_lookup_stats(struct flow_table *tbl,
ce = NULL;
hash = skb_hash;
- entries = this_cpu_ptr(tbl->mask_cache);
+ entries = this_cpu_ptr(mc->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);
+ int index = hash & (mc->cache_size - 1);
struct mask_cache_entry *e;
e = &entries[index];
if (e->skb_hash == skb_hash) {
flow = flow_lookup(tbl, ti, ma, key, n_mask_hit,
- &e->mask_index);
+ n_cache_hit, &e->mask_index);
if (!flow)
e->skb_hash = 0;
return flow;
@@ -693,10 +837,12 @@ struct sw_flow *ovs_flow_tbl_lookup_stats(struct flow_table *tbl,
}
/* Cache miss, do full lookup. */
- flow = flow_lookup(tbl, ti, ma, key, n_mask_hit, &ce->mask_index);
+ flow = flow_lookup(tbl, ti, ma, key, n_mask_hit, n_cache_hit,
+ &ce->mask_index);
if (flow)
ce->skb_hash = skb_hash;
+ *n_cache_hit = 0;
return flow;
}
@@ -706,9 +852,18 @@ struct sw_flow *ovs_flow_tbl_lookup(struct flow_table *tbl,
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 n_cache_hit;
+ struct sw_flow *flow;
u32 index = 0;
- return flow_lookup(tbl, ti, ma, key, &n_mask_hit, &index);
+ /* This function gets called trough the netlink interface and therefore
+ * is preemptible. However, flow_lookup() function needs to be called
+ * with BH disabled due to CPU specific variables.
+ */
+ local_bh_disable();
+ flow = flow_lookup(tbl, ti, ma, key, &n_mask_hit, &n_cache_hit, &index);
+ local_bh_enable();
+ return flow;
}
struct sw_flow *ovs_flow_tbl_lookup_exact(struct flow_table *tbl,
@@ -752,7 +907,8 @@ static bool ovs_flow_cmp_ufid(const struct sw_flow *flow,
return !memcmp(flow->id.ufid, sfid->ufid, sfid->ufid_len);
}
-bool ovs_flow_cmp(const struct sw_flow *flow, const struct sw_flow_match *match)
+bool ovs_flow_cmp(const struct sw_flow *flow,
+ const struct sw_flow_match *match)
{
if (ovs_identifier_is_ufid(&flow->id))
return flow_cmp_masked_key(flow, match->key, &match->range);
@@ -771,7 +927,7 @@ struct sw_flow *ovs_flow_tbl_lookup_ufid(struct flow_table *tbl,
hash = ufid_hash(ufid);
head = find_bucket(ti, hash);
hlist_for_each_entry_rcu(flow, head, ufid_table.node[ti->node_ver],
- lockdep_ovsl_is_held()) {
+ lockdep_ovsl_is_held()) {
if (flow->ufid_table.hash == hash &&
ovs_flow_cmp_ufid(flow, ufid))
return flow;
@@ -785,6 +941,13 @@ int ovs_flow_tbl_num_masks(const struct flow_table *table)
return READ_ONCE(ma->count);
}
+u32 ovs_flow_tbl_masks_cache_size(const struct flow_table *table)
+{
+ struct mask_cache *mc = rcu_dereference_ovsl(table->mask_cache);
+
+ return READ_ONCE(mc->cache_size);
+}
+
static struct table_instance *table_instance_expand(struct table_instance *ti,
bool ufid)
{
@@ -798,7 +961,7 @@ void ovs_flow_tbl_remove(struct flow_table *table, struct sw_flow *flow)
struct table_instance *ufid_ti = ovsl_dereference(table->ufid_ti);
BUG_ON(table->count == 0);
- table_instance_flow_free(table, ti, ufid_ti, flow, true);
+ table_instance_flow_free(table, ti, ufid_ti, flow);
}
static struct sw_flow_mask *mask_alloc(void)
@@ -932,6 +1095,99 @@ int ovs_flow_tbl_insert(struct flow_table *table, struct sw_flow *flow,
return 0;
}
+static int compare_mask_and_count(const void *a, const void *b)
+{
+ const struct mask_count *mc_a = a;
+ const struct mask_count *mc_b = b;
+
+ return (s64)mc_b->counter - (s64)mc_a->counter;
+}
+
+/* Must be called with OVS mutex held. */
+void ovs_flow_masks_rebalance(struct flow_table *table)
+{
+ struct mask_array *ma = rcu_dereference_ovsl(table->mask_array);
+ struct mask_count *masks_and_count;
+ struct mask_array *new;
+ int masks_entries = 0;
+ int i;
+
+ /* Build array of all current entries with use counters. */
+ masks_and_count = kmalloc_array(ma->max, sizeof(*masks_and_count),
+ GFP_KERNEL);
+ if (!masks_and_count)
+ return;
+
+ for (i = 0; i < ma->max; i++) {
+ struct sw_flow_mask *mask;
+ int cpu;
+
+ mask = rcu_dereference_ovsl(ma->masks[i]);
+ if (unlikely(!mask))
+ break;
+
+ masks_and_count[i].index = i;
+ masks_and_count[i].counter = 0;
+
+ for_each_possible_cpu(cpu) {
+ struct mask_array_stats *stats;
+ unsigned int start;
+ u64 counter;
+
+ stats = per_cpu_ptr(ma->masks_usage_stats, cpu);
+ do {
+ start = u64_stats_fetch_begin_irq(&stats->syncp);
+ counter = stats->usage_cntrs[i];
+ } while (u64_stats_fetch_retry_irq(&stats->syncp,
+ start));
+
+ masks_and_count[i].counter += counter;
+ }
+
+ /* Subtract the zero count value. */
+ masks_and_count[i].counter -= ma->masks_usage_zero_cntr[i];
+
+ /* Rather than calling tbl_mask_array_reset_counters()
+ * below when no change is needed, do it inline here.
+ */
+ ma->masks_usage_zero_cntr[i] += masks_and_count[i].counter;
+ }
+
+ if (i == 0)
+ goto free_mask_entries;
+
+ /* Sort the entries */
+ masks_entries = i;
+ sort(masks_and_count, masks_entries, sizeof(*masks_and_count),
+ compare_mask_and_count, NULL);
+
+ /* If the order is the same, nothing to do... */
+ for (i = 0; i < masks_entries; i++) {
+ if (i != masks_and_count[i].index)
+ break;
+ }
+ if (i == masks_entries)
+ goto free_mask_entries;
+
+ /* Rebuilt the new list in order of usage. */
+ new = tbl_mask_array_alloc(ma->max);
+ if (!new)
+ goto free_mask_entries;
+
+ for (i = 0; i < masks_entries; i++) {
+ int index = masks_and_count[i].index;
+
+ if (ovsl_dereference(ma->masks[index]))
+ new->masks[new->count++] = ma->masks[index];
+ }
+
+ rcu_assign_pointer(table->mask_array, new);
+ call_rcu(&ma->rcu, mask_array_rcu_cb);
+
+free_mask_entries:
+ kfree(masks_and_count);
+}
+
/* Initializes the flow module.
* Returns zero if successful or a negative error code. */
int ovs_flow_init(void)