1 files changed, 267 insertions, 20 deletions

diff --git a/net/openvswitch/flow_table.c b/net/openvswitch/flow_table.c
index 2398d7238300..8c12675cbb67 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;
@@ -169,16 +170,70 @@ static struct table_instance *table_instance_alloc(int new_size)
 	return ti;
 }
 
+static void __mask_array_destroy(struct mask_array *ma)
+{
+	free_percpu(ma->masks_usage_cntr);
+	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) {
+			u64 *usage_counters = per_cpu_ptr(ma->masks_usage_cntr,
+							  cpu);
+			unsigned int start;
+			u64 counter;
+
+			do {
+				start = u64_stats_fetch_begin_irq(&ma->syncp);
+				counter = usage_counters[i];
+			} while (u64_stats_fetch_retry_irq(&ma->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_cntr = __alloc_percpu(sizeof(u64) * size,
+					       __alignof__(u64));
+	if (!new->masks_usage_cntr) {
+		kfree(new);
+		return NULL;
+	}
+
 	new->count = 0;
 	new->max = size;
 
@@ -202,10 +257,10 @@ 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;
 }
@@ -223,6 +278,11 @@ static int tbl_mask_array_add_mask(struct flow_table *tbl,
 			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]));
@@ -260,6 +320,9 @@ 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 +341,79 @@ 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(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 +431,7 @@ 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;
@@ -312,9 +440,9 @@ 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;
 }
 
@@ -390,9 +518,11 @@ 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);
+	call_rcu(&mc->rcu, mask_cache_rcu_cb);
+	call_rcu(&ma->rcu, mask_array_rcu_cb);
 	table_instance_destroy(table, ti, ufid_ti, false);
 }
 
@@ -604,8 +734,10 @@ static struct sw_flow *flow_lookup(struct flow_table *tbl,
 				   struct mask_array *ma,
 				   const struct sw_flow_key *key,
 				   u32 *n_mask_hit,
+				   u32 *n_cache_hit,
 				   u32 *index)
 {
+	u64 *usage_counters = this_cpu_ptr(ma->masks_usage_cntr);
 	struct sw_flow *flow;
 	struct sw_flow_mask *mask;
 	int i;
@@ -614,8 +746,13 @@ 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(&ma->syncp);
+				usage_counters[*index]++;
+				u64_stats_update_end(&ma->syncp);
+				(*n_cache_hit)++;
 				return flow;
+			}
 		}
 	}
 
@@ -631,6 +768,9 @@ 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(&ma->syncp);
+			usage_counters[*index]++;
+			u64_stats_update_end(&ma->syncp);
 			return flow;
 		}
 	}
@@ -648,8 +788,10 @@ 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;
@@ -658,10 +800,13 @@ 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
@@ -672,17 +817,17 @@ 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;
@@ -695,10 +840,12 @@ 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;
 }
 
@@ -708,9 +855,10 @@ 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;
 	u32 index = 0;
 
-	return flow_lookup(tbl, ti, ma, key, &n_mask_hit, &index);
+	return flow_lookup(tbl, ti, ma, key, &n_mask_hit, &n_cache_hit, &index);
 }
 
 struct sw_flow *ovs_flow_tbl_lookup_exact(struct flow_table *tbl,
@@ -787,6 +935,13 @@ 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)
 {
@@ -934,6 +1089,98 @@ 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;
+		unsigned int start;
+		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) {
+			u64 *usage_counters = per_cpu_ptr(ma->masks_usage_cntr,
+							  cpu);
+			u64 counter;
+
+			do {
+				start = u64_stats_fetch_begin_irq(&ma->syncp);
+				counter = usage_counters[i];
+			} while (u64_stats_fetch_retry_irq(&ma->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)