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Message-ID: <CAMDZJNV9LndPTgDdFOJv7SUMiidTdUh+L=hysGBhKAGXDbzBDA@mail.gmail.com>
Date: Tue, 8 Oct 2019 09:44:26 +0800
From: Tonghao Zhang <xiangxia.m.yue@...il.com>
To: Pravin Shelar <pshelar@....org>
Cc: Greg Rose <gvrose8192@...il.com>,
Linux Kernel Network Developers <netdev@...r.kernel.org>
Subject: Re: [PATCH net-next 2/9] net: openvswitch: convert mask list in mask array
On Wed, Oct 2, 2019 at 10:02 AM Pravin Shelar <pshelar@....org> wrote:
>
> On Sun, Sep 29, 2019 at 7:09 PM <xiangxia.m.yue@...il.com> wrote:
> >
> > From: Tonghao Zhang <xiangxia.m.yue@...il.com>
> >
> > 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@...il.com>
> > ---
> > net/openvswitch/flow.h | 1 -
> > net/openvswitch/flow_table.c | 218 +++++++++++++++++++++++++++++++++----------
> > net/openvswitch/flow_table.h | 8 +-
> > 3 files changed, 175 insertions(+), 52 deletions(-)
> >
> > diff --git a/net/openvswitch/flow.h b/net/openvswitch/flow.h
> > index b830d5f..8080518 100644
> > --- a/net/openvswitch/flow.h
> > +++ b/net/openvswitch/flow.h
> > @@ -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;
> > };
> > diff --git a/net/openvswitch/flow_table.c b/net/openvswitch/flow_table.c
> > index 3d515c0..99954fa 100644
> > --- a/net/openvswitch/flow_table.c
> > +++ b/net/openvswitch/flow_table.c
> > @@ -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
> > @@ -168,9 +169,59 @@ 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;
> > +
> > + 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);
> > +
> > + if (old)
> > + call_rcu(&old->rcu, mask_array_rcu_cb);
> > +
> kfree_rcu can be used instead of call_rcu.
will be changed in v2. thanks.
>
> > + 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,
> > @@ -178,9 +229,13 @@ int ovs_flow_tbl_init(struct flow_table *table)
> > 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)
> > @@ -188,7 +243,7 @@ int ovs_flow_tbl_init(struct flow_table *table)
> >
> > 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;
> > @@ -196,6 +251,8 @@ int ovs_flow_tbl_init(struct flow_table *table)
> >
> > free_ti:
> > __table_instance_destroy(ti);
> > +free_mask_array:
> > + kfree(ma);
> > free_mask_cache:
> > free_percpu(table->mask_cache);
> > return -ENOMEM;
> > @@ -255,6 +312,7 @@ 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_dereference_raw(table->mask_array));
> > table_instance_destroy(ti, ufid_ti, false);
> > }
> >
> > @@ -460,17 +518,27 @@ 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;
> > }
> >
> > @@ -486,6 +554,7 @@ 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;
> > @@ -493,8 +562,11 @@ 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);
> > @@ -507,37 +579,33 @@ 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;
> > }
> > @@ -546,26 +614,38 @@ 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;
> > }
> >
> > @@ -611,13 +691,8 @@ 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;
> > -
> > - list_for_each_entry(mask, &table->mask_list, list)
> > - num++;
> > -
> > - return num;
> > + struct mask_array *ma = rcu_dereference_ovsl(table->mask_array);
> > + return ma->count;
> > }
> >
> > static struct table_instance *table_instance_expand(struct table_instance *ti,
> > @@ -638,8 +713,19 @@ 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();
> > }
> > }
> > }
> > @@ -689,13 +775,16 @@ 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;
> > @@ -706,15 +795,44 @@ 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++;
> > diff --git a/net/openvswitch/flow_table.h b/net/openvswitch/flow_table.h
> > index 04b6b1c..8a5cea6 100644
> > --- a/net/openvswitch/flow_table.h
> > +++ b/net/openvswitch/flow_table.h
> > @@ -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;
> > @@ -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;
> > --
> > 1.8.3.1
> >
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