[ovs-dev] [PATCH V2 3/4] datapath: Convert mask list in mask array.
Pravin B Shelar
pshelar at nicira.com
Wed Apr 23 15:49:44 UTC 2014
mask caches index of mask in mask_list. On packet recv OVS
need to traverse mask-list to get cached mask. Therefore array
is better for retrieving cached mask. This also allows better
cache replacement algorithm by directly checking mask's existence.
Signed-off-by: Pravin B Shelar <pshelar at nicira.com>
---
datapath/flow.h | 1 -
datapath/flow_table.c | 200 ++++++++++++++++++++++++++++++++++++++-----------
datapath/flow_table.h | 8 +-
3 files changed, 163 insertions(+), 46 deletions(-)
diff --git a/datapath/flow.h b/datapath/flow.h
index d05a9f4..2018691 100644
--- a/datapath/flow.h
+++ b/datapath/flow.h
@@ -127,7 +127,6 @@ struct sw_flow_key_range {
struct sw_flow_mask {
int ref_count;
struct rcu_head rcu;
- struct list_head list;
struct sw_flow_key_range range;
struct sw_flow_key key;
};
diff --git a/datapath/flow_table.c b/datapath/flow_table.c
index cc0eaf2..c8bd9d1 100644
--- a/datapath/flow_table.c
+++ b/datapath/flow_table.c
@@ -47,6 +47,7 @@
#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
@@ -211,26 +212,83 @@ static struct table_instance *table_instance_alloc(int new_size)
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++) {
+ if (old->masks[i])
+ new->masks[new->count++] = old->masks[i];
+ }
+ }
+ rcu_assign_pointer(tbl->mask_array, new);
+
+ if (old)
+ call_rcu(&old->rcu, mask_array_rcu_cb);
+
+ return 0;
+}
+
int ovs_flow_tbl_init(struct flow_table *table)
{
struct table_instance *ti;
+ 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)
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) {
- free_percpu(table->mask_cache);
- return -ENOMEM;
- }
+ if (!ti)
+ 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)
@@ -276,6 +334,7 @@ void ovs_flow_tbl_destroy(struct flow_table *table)
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);
}
@@ -457,17 +516,27 @@ static struct sw_flow *masked_flow_lookup(struct table_instance *ti,
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_mask_hit,
+ u32 *index)
{
- struct sw_flow_mask *mask;
struct sw_flow *flow;
+ int i;
- list_for_each_entry_rcu(mask, &tbl->mask_list, list) {
- flow = masked_flow_lookup(ti, key, mask, n_mask_hit);
- if (flow) /* Found */
- return flow;
+ for (i = 0; i < ma->max; i++) {
+ struct sw_flow_mask *mask;
+
+ mask = rcu_dereference_ovsl(ma->masks[i]);
+ if (mask) {
+ flow = masked_flow_lookup(ti, key, mask, n_mask_hit);
+ if (flow) { /* Found */
+ *index = i;
+ return flow;
+ }
+ }
}
+
return NULL;
}
@@ -483,6 +552,7 @@ struct sw_flow *ovs_flow_tbl_lookup_stats(struct flow_table *tbl,
u32 skb_hash,
u32 *n_mask_hit)
{
+ struct mask_array *ma = rcu_dereference_ovsl(tbl->mask_array);
struct table_instance *ti = rcu_dereference_ovsl(tbl->ti);
struct mask_cache_entry *entries, *ce, *del;
struct sw_flow *flow;
@@ -490,8 +560,11 @@ struct sw_flow *ovs_flow_tbl_lookup_stats(struct flow_table *tbl,
int seg;
*n_mask_hit = 0;
- if (unlikely(!skb_hash))
- return flow_lookup(tbl, ti, key, n_mask_hit);
+ if (unlikely(!skb_hash)) {
+ u32 __always_unused mask_index;
+
+ return flow_lookup(tbl, ti, ma, key, n_mask_hit, &mask_index);
+ }
del = NULL;
entries = this_cpu_ptr(tbl->mask_cache);
@@ -504,36 +577,33 @@ struct sw_flow *ovs_flow_tbl_lookup_stats(struct flow_table *tbl,
if (ce->skb_hash == skb_hash) {
struct sw_flow_mask *mask;
- int i;
+ struct sw_flow *flow;
- i = 0;
- list_for_each_entry_rcu(mask, &tbl->mask_list, list) {
- if (ce->mask_index == i++) {
- flow = masked_flow_lookup(ti, key, mask,
- n_mask_hit);
- if (flow) /* Found */
- return flow;
+ mask = rcu_dereference_ovsl(ma->masks[ce->mask_index]);
+ if (mask) {
+ flow = masked_flow_lookup(ti, key, mask,
+ n_mask_hit);
+ if (flow) /* Found */
+ return flow;
- break;
- }
}
del = ce;
break;
}
- if (!del || (del->skb_hash && !ce->skb_hash)) {
+ if (!del || (del->skb_hash && !ce->skb_hash) ||
+ (rcu_dereference_ovsl(ma->masks[del->mask_index]) &&
+ !rcu_dereference_ovsl(ma->masks[ce->mask_index]))) {
del = ce;
}
hash >>= MC_HASH_SHIFT;
}
- flow = flow_lookup(tbl, ti, key, n_mask_hit);
-
- if (flow) {
+ flow = flow_lookup(tbl, ti, ma, key, n_mask_hit, &del->mask_index);
+ if (flow)
del->skb_hash = skb_hash;
- del->mask_index = (*n_mask_hit - 1);
- }
+
return flow;
}
@@ -541,21 +611,20 @@ 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;
n_mask_hit = 0;
- return flow_lookup(tbl, ti, 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_mask *mask;
- int num = 0;
-
- list_for_each_entry(mask, &table->mask_list, list)
- num++;
+ 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)
@@ -575,7 +644,19 @@ static void flow_mask_remove(struct flow_table *tbl, struct sw_flow_mask *mask)
mask->ref_count--;
if (!mask->ref_count) {
- list_del_rcu(&mask->list);
+ struct mask_array *ma;
+ int i;
+
+ ma = ovsl_dereference(tbl->mask_array);
+ for (i = 0; i < ma->max; i++) {
+ if (mask == ovsl_dereference(ma->masks[i])) {
+ RCU_INIT_POINTER(ma->masks[i], NULL);
+ ma->count--;
+ goto free;
+ }
+ }
+ BUG();
+free:
call_rcu(&mask->rcu, rcu_free_sw_flow_mask_cb);
}
}
@@ -620,13 +701,16 @@ static bool mask_equal(const struct sw_flow_mask *a,
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->max; 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;
@@ -637,15 +721,43 @@ static int flow_mask_insert(struct flow_table *tbl, struct sw_flow *flow,
struct sw_flow_mask *new)
{
struct sw_flow_mask *mask;
+
mask = flow_mask_find(tbl, new);
if (!mask) {
+ struct mask_array *ma;
+ int i;
+
/* Allocate a new mask if none exsits. */
mask = mask_alloc();
if (!mask)
return -ENOMEM;
+
mask->key = new->key;
mask->range = new->range;
- list_add_tail_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);
+ }
+ for (i = 0; i < ma->max; i++) {
+ const struct sw_flow_mask *t;
+
+ t = ovsl_dereference(ma->masks[i]);
+ if (!t) {
+ rcu_assign_pointer(ma->masks[i], mask);
+ ma->count++;
+ break;
+ }
+ }
} else {
BUG_ON(!mask->ref_count);
mask->ref_count++;
diff --git a/datapath/flow_table.h b/datapath/flow_table.h
index 281d1da..ee86953 100644
--- a/datapath/flow_table.h
+++ b/datapath/flow_table.h
@@ -41,6 +41,12 @@ struct mask_cache_entry {
u32 mask_index;
};
+struct mask_array {
+ struct rcu_head rcu;
+ int count, max;
+ struct sw_flow_mask __rcu *masks[];
+};
+
struct table_instance {
struct flex_array *buckets;
unsigned int n_buckets;
@@ -53,7 +59,7 @@ struct table_instance {
struct flow_table {
struct table_instance __rcu *ti;
struct mask_cache_entry __percpu *mask_cache;
- struct list_head mask_list;
+ struct mask_array __rcu *mask_array;
unsigned long last_rehash;
unsigned int count;
};
--
1.7.9.5
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