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net: openvswitch: convert mask list in mask array
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Port the codes to linux upstream and with little changes.

Pravin B Shelar, says:
| 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.

Link: https://github.com/openvswitch/ovs/commit/d49fc3ff53c65e4eca9cabd52ac63396746a7ef5
Signed-off-by: Tonghao Zhang <xiangxia.m.yue@gmail.com>
Tested-by: Greg Rose <gvrose8192@gmail.com>
Acked-by: William Tu <u9012063@gmail.com>
Signed-off-by: Pravin B Shelar <pshelar@ovn.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Tonghao Zhang authored and David S. Miller committed Nov 4, 2019
1 parent 04b7d13 commit 4bc63b1
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Showing 3 changed files with 167 additions and 51 deletions.
1 change: 0 additions & 1 deletion net/openvswitch/flow.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -166,7 +166,6 @@ 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;
};
Expand Down
209 changes: 160 additions & 49 deletions net/openvswitch/flow_table.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -34,6 +34,7 @@
#include <net/ndisc.h>

#define TBL_MIN_BUCKETS 1024
#define MASK_ARRAY_SIZE_MIN 16
#define REHASH_INTERVAL (10 * 60 * HZ)

#define MC_HASH_SHIFT 8
Expand Down Expand Up @@ -168,34 +169,82 @@ static struct table_instance *table_instance_alloc(int new_size)
return ti;
}

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);
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 (ovsl_dereference(old->masks[i]))
new->masks[new->count++] = old->masks[i];
}
}

rcu_assign_pointer(tbl->mask_array, new);
kfree_rcu(old, rcu);

return 0;
}

int ovs_flow_tbl_init(struct flow_table *table)
{
struct table_instance *ti, *ufid_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)
goto free_mask_cache;
goto free_mask_array;

ufid_ti = table_instance_alloc(TBL_MIN_BUCKETS);
if (!ufid_ti)
goto free_ti;

rcu_assign_pointer(table->ti, ti);
rcu_assign_pointer(table->ufid_ti, ufid_ti);
INIT_LIST_HEAD(&table->mask_list);
rcu_assign_pointer(table->mask_array, ma);
table->last_rehash = jiffies;
table->count = 0;
table->ufid_count = 0;
return 0;

free_ti:
__table_instance_destroy(ti);
free_mask_array:
kfree(ma);
free_mask_cache:
free_percpu(table->mask_cache);
return -ENOMEM;
Expand Down Expand Up @@ -255,6 +304,7 @@ void ovs_flow_tbl_destroy(struct flow_table *table)
struct table_instance *ufid_ti = rcu_dereference_raw(table->ufid_ti);

free_percpu(table->mask_cache);
kfree_rcu(rcu_dereference_raw(table->mask_array), rcu);
table_instance_destroy(ti, ufid_ti, false);
}

Expand Down Expand Up @@ -460,17 +510,27 @@ 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;
}

Expand All @@ -486,15 +546,19 @@ 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;
u32 hash = skb_hash;
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);
Expand All @@ -507,37 +571,33 @@ 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;

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;

break;
}
struct sw_flow *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;
}

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);
flow = flow_lookup(tbl, ti, ma, key, n_mask_hit, &del->mask_index);

if (flow) {
if (flow)
del->skb_hash = skb_hash;
del->mask_index = (*n_mask_hit - 1);
}

return flow;
}
Expand All @@ -546,26 +606,38 @@ 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 flow_lookup(tbl, ti, key, &n_mask_hit);
return flow_lookup(tbl, ti, ma, key, &n_mask_hit, &index);
}

struct sw_flow *ovs_flow_tbl_lookup_exact(struct flow_table *tbl,
const struct sw_flow_match *match)
{
struct table_instance *ti = rcu_dereference_ovsl(tbl->ti);
struct sw_flow_mask *mask;
struct sw_flow *flow;
u32 __always_unused n_mask_hit;
struct mask_array *ma = ovsl_dereference(tbl->mask_array);
int i;

/* Always called under ovs-mutex. */
list_for_each_entry(mask, &tbl->mask_list, list) {
for (i = 0; i < ma->max; i++) {
struct table_instance *ti = rcu_dereference_ovsl(tbl->ti);
u32 __always_unused n_mask_hit;
struct sw_flow_mask *mask;
struct sw_flow *flow;

mask = ovsl_dereference(ma->masks[i]);
if (!mask)
continue;

flow = masked_flow_lookup(ti, match->key, mask, &n_mask_hit);
if (flow && ovs_identifier_is_key(&flow->id) &&
ovs_flow_cmp_unmasked_key(flow, match))
ovs_flow_cmp_unmasked_key(flow, match)) {
return flow;
}
}

return NULL;
}

Expand Down Expand Up @@ -611,13 +683,9 @@ struct sw_flow *ovs_flow_tbl_lookup_ufid(struct flow_table *tbl,

int ovs_flow_tbl_num_masks(const struct flow_table *table)
{
struct sw_flow_mask *mask;
int num = 0;
struct mask_array *ma = rcu_dereference_ovsl(table->mask_array);

list_for_each_entry(mask, &table->mask_list, list)
num++;

return num;
return ma->count;
}

static struct table_instance *table_instance_expand(struct table_instance *ti,
Expand All @@ -638,8 +706,19 @@ 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);
kfree_rcu(mask, rcu);
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--;
kfree_rcu(mask, rcu);
return;
}
}
BUG();
}
}
}
Expand Down Expand Up @@ -689,13 +768,16 @@ 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;

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;
ma = ovsl_dereference(tbl->mask_array);
for (i = 0; i < ma->max; i++) {
struct sw_flow_mask *t;
t = ovsl_dereference(ma->masks[i]);

if (t && mask_equal(mask, t))
return t;
}

return NULL;
Expand All @@ -706,15 +788,44 @@ static int flow_mask_insert(struct flow_table *tbl, struct sw_flow *flow,
const 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++;
Expand Down
8 changes: 7 additions & 1 deletion net/openvswitch/flow_table.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -27,6 +27,12 @@ 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 hlist_head *buckets;
unsigned int n_buckets;
Expand All @@ -40,7 +46,7 @@ struct flow_table {
struct table_instance __rcu *ti;
struct table_instance __rcu *ufid_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;
unsigned int ufid_count;
Expand Down

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