Merge branch 'ovs-meter-tables'

Tonghao Zhang says:

====================
openvswitch: expand meter tables and fix bug

The patch set expand or shrink the meter table when necessary.
and other patches fix bug or improve codes.
====================

Signed-off-by: David S. Miller <[e-mail]>

net/openvswitch/datapath.h

···
 	u32 max_headroom;
 
 	/* Switch meters. */
-	struct hlist_head *meters;
+	struct dp_meter_table meter_tbl;
 };
 
 /**

net/openvswitch/meter.c

···
 #include <linux/openvswitch.h>
 #include <linux/netlink.h>
 #include <linux/rculist.h>
+#include <linux/swap.h>
 
 #include <net/netlink.h>
 #include <net/genetlink.h>
 
 #include "datapath.h"
 #include "meter.h"
-
-#define METER_HASH_BUCKETS 1024
 
 static const struct nla_policy meter_policy[OVS_METER_ATTR_MAX + 1] = {
 	[OVS_METER_ATTR_ID] = { .type = NLA_U32, },
···
 	[OVS_BAND_ATTR_STATS] = { .len = sizeof(struct ovs_flow_stats) },
 };
 
+static u32 meter_hash(struct dp_meter_instance *ti, u32 id)
+{
+	return id % ti->n_meters;
+}
+
 static void ovs_meter_free(struct dp_meter *meter)
 {
 	if (!meter)
···
 	kfree_rcu(meter, rcu);
 }
 
-static struct hlist_head *meter_hash_bucket(const struct datapath *dp,
-					    u32 meter_id)
-{
-	return &dp->meters[meter_id & (METER_HASH_BUCKETS - 1)];
-}
-
 /* Call with ovs_mutex or RCU read lock. */
-static struct dp_meter *lookup_meter(const struct datapath *dp,
+static struct dp_meter *lookup_meter(const struct dp_meter_table *tbl,
 				     u32 meter_id)
 {
+	struct dp_meter_instance *ti = rcu_dereference_ovsl(tbl->ti);
+	u32 hash = meter_hash(ti, meter_id);
 	struct dp_meter *meter;
-	struct hlist_head *head;
 
-	head = meter_hash_bucket(dp, meter_id);
-	hlist_for_each_entry_rcu(meter, head, dp_hash_node,
-				lockdep_ovsl_is_held()) {
-		if (meter->id == meter_id)
-			return meter;
-	}
+	meter = rcu_dereference_ovsl(ti->dp_meters[hash]);
+	if (meter && likely(meter->id == meter_id))
+		return meter;
+
 	return NULL;
 }
 
-static void attach_meter(struct datapath *dp, struct dp_meter *meter)
+static struct dp_meter_instance *dp_meter_instance_alloc(const u32 size)
 {
-	struct hlist_head *head = meter_hash_bucket(dp, meter->id);
+	struct dp_meter_instance *ti;
 
-	hlist_add_head_rcu(&meter->dp_hash_node, head);
+	ti = kvzalloc(sizeof(*ti) +
+		      sizeof(struct dp_meter *) * size,
+		      GFP_KERNEL);
+	if (!ti)
+		return NULL;
+
+	ti->n_meters = size;
+
+	return ti;
 }
 
-static void detach_meter(struct dp_meter *meter)
+static void dp_meter_instance_free(struct dp_meter_instance *ti)
 {
+	kvfree(ti);
+}
+
+static void dp_meter_instance_free_rcu(struct rcu_head *rcu)
+{
+	struct dp_meter_instance *ti;
+
+	ti = container_of(rcu, struct dp_meter_instance, rcu);
+	kvfree(ti);
+}
+
+static int
+dp_meter_instance_realloc(struct dp_meter_table *tbl, u32 size)
+{
+	struct dp_meter_instance *ti = rcu_dereference_ovsl(tbl->ti);
+	int n_meters = min(size, ti->n_meters);
+	struct dp_meter_instance *new_ti;
+	int i;
+
+	new_ti = dp_meter_instance_alloc(size);
+	if (!new_ti)
+		return -ENOMEM;
+
+	for (i = 0; i < n_meters; i++)
+		new_ti->dp_meters[i] =
+			rcu_dereference_ovsl(ti->dp_meters[i]);
+
+	rcu_assign_pointer(tbl->ti, new_ti);
+	call_rcu(&ti->rcu, dp_meter_instance_free_rcu);
+
+	return 0;
+}
+
+static void dp_meter_instance_insert(struct dp_meter_instance *ti,
+				     struct dp_meter *meter)
+{
+	u32 hash;
+
+	hash = meter_hash(ti, meter->id);
+	rcu_assign_pointer(ti->dp_meters[hash], meter);
+}
+
+static void dp_meter_instance_remove(struct dp_meter_instance *ti,
+				     struct dp_meter *meter)
+{
+	u32 hash;
+
+	hash = meter_hash(ti, meter->id);
+	RCU_INIT_POINTER(ti->dp_meters[hash], NULL);
+}
+
+static int attach_meter(struct dp_meter_table *tbl, struct dp_meter *meter)
+{
+	struct dp_meter_instance *ti = rcu_dereference_ovsl(tbl->ti);
+	u32 hash = meter_hash(ti, meter->id);
+	int err;
+
+	/* In generally, slots selected should be empty, because
+	 * OvS uses id-pool to fetch a available id.
+	 */
+	if (unlikely(rcu_dereference_ovsl(ti->dp_meters[hash])))
+		return -EBUSY;
+
+	dp_meter_instance_insert(ti, meter);
+
+	/* That function is thread-safe. */
+	tbl->count++;
+	if (tbl->count >= tbl->max_meters_allowed) {
+		err = -EFBIG;
+		goto attach_err;
+	}
+
+	if (tbl->count >= ti->n_meters &&
+	    dp_meter_instance_realloc(tbl, ti->n_meters * 2)) {
+		err = -ENOMEM;
+		goto attach_err;
+	}
+
+	return 0;
+
+attach_err:
+	dp_meter_instance_remove(ti, meter);
+	tbl->count--;
+	return err;
+}
+
+static int detach_meter(struct dp_meter_table *tbl, struct dp_meter *meter)
+{
+	struct dp_meter_instance *ti;
+
 	ASSERT_OVSL();
-	if (meter)
-		hlist_del_rcu(&meter->dp_hash_node);
+	if (!meter)
+		return 0;
+
+	ti = rcu_dereference_ovsl(tbl->ti);
+	dp_meter_instance_remove(ti, meter);
+
+	tbl->count--;
+
+	/* Shrink the meter array if necessary. */
+	if (ti->n_meters > DP_METER_ARRAY_SIZE_MIN &&
+	    tbl->count <= (ti->n_meters / 4)) {
+		int half_size = ti->n_meters / 2;
+		int i;
+
+		/* Avoid hash collision, don't move slots to other place.
+		 * Make sure there are no references of meters in array
+		 * which will be released.
+		 */
+		for (i = half_size; i < ti->n_meters; i++)
+			if (rcu_dereference_ovsl(ti->dp_meters[i]))
+				goto out;
+
+		if (dp_meter_instance_realloc(tbl, half_size))
+			goto shrink_err;
+	}
+
+out:
+	return 0;
+
+shrink_err:
+	dp_meter_instance_insert(ti, meter);
+	tbl->count++;
+	return -ENOMEM;
 }
 
 static struct sk_buff *
···
 	if (nla_put_u32(reply, OVS_METER_ATTR_ID, meter_id))
 		goto error;
 
-	if (!meter)
-		return 0;
-
 	if (nla_put(reply, OVS_METER_ATTR_STATS,
-		    sizeof(struct ovs_flow_stats), &meter->stats) ||
-	    nla_put_u64_64bit(reply, OVS_METER_ATTR_USED, meter->used,
+		    sizeof(struct ovs_flow_stats), &meter->stats))
+		goto error;
+
+	if (nla_put_u64_64bit(reply, OVS_METER_ATTR_USED, meter->used,
 			      OVS_METER_ATTR_PAD))
 		goto error;
 
···
 
 static int ovs_meter_cmd_features(struct sk_buff *skb, struct genl_info *info)
 {
-	struct sk_buff *reply;
+	struct ovs_header *ovs_header = info->userhdr;
 	struct ovs_header *ovs_reply_header;
 	struct nlattr *nla, *band_nla;
-	int err;
+	struct sk_buff *reply;
+	struct datapath *dp;
+	int err = -EMSGSIZE;
 
 	reply = ovs_meter_cmd_reply_start(info, OVS_METER_CMD_FEATURES,
 					  &ovs_reply_header);
 	if (IS_ERR(reply))
 		return PTR_ERR(reply);
 
-	if (nla_put_u32(reply, OVS_METER_ATTR_MAX_METERS, U32_MAX) ||
-	    nla_put_u32(reply, OVS_METER_ATTR_MAX_BANDS, DP_MAX_BANDS))
+	ovs_lock();
+	dp = get_dp(sock_net(skb->sk), ovs_header->dp_ifindex);
+	if (!dp) {
+		err = -ENODEV;
+		goto exit_unlock;
+	}
+
+	if (nla_put_u32(reply, OVS_METER_ATTR_MAX_METERS,
+			dp->meter_tbl.max_meters_allowed))
+		goto exit_unlock;
+
+	ovs_unlock();
+
+	if (nla_put_u32(reply, OVS_METER_ATTR_MAX_BANDS, DP_MAX_BANDS))
 		goto nla_put_failure;
 
 	nla = nla_nest_start_noflag(reply, OVS_METER_ATTR_BANDS);
···
 	genlmsg_end(reply, ovs_reply_header);
 	return genlmsg_reply(reply, info);
 
+exit_unlock:
+	ovs_unlock();
 nla_put_failure:
 	nlmsg_free(reply);
-	err = -EMSGSIZE;
 	return err;
 }
 
···
 		 *
 		 * Start with a full bucket.
 		 */
-		band->bucket = (band->burst_size + band->rate) * 1000;
+		band->bucket = (band->burst_size + band->rate) * 1000ULL;
 		band_max_delta_t = band->bucket / band->rate;
 		if (band_max_delta_t > meter->max_delta_t)
 			meter->max_delta_t = band_max_delta_t;
···
 	struct sk_buff *reply;
 	struct ovs_header *ovs_reply_header;
 	struct ovs_header *ovs_header = info->userhdr;
+	struct dp_meter_table *meter_tbl;
 	struct datapath *dp;
 	int err;
 	u32 meter_id;
 	bool failed;
 
-	if (!a[OVS_METER_ATTR_ID]) {
-		return -ENODEV;
-	}
+	if (!a[OVS_METER_ATTR_ID])
+		return -EINVAL;
 
 	meter = dp_meter_create(a);
 	if (IS_ERR_OR_NULL(meter))
···
 		goto exit_unlock;
 	}
 
+	meter_tbl = &dp->meter_tbl;
 	meter_id = nla_get_u32(a[OVS_METER_ATTR_ID]);
 
-	/* Cannot fail after this. */
-	old_meter = lookup_meter(dp, meter_id);
-	detach_meter(old_meter);
-	attach_meter(dp, meter);
+	old_meter = lookup_meter(meter_tbl, meter_id);
+	err = detach_meter(meter_tbl, old_meter);
+	if (err)
+		goto exit_unlock;
+
+	err = attach_meter(meter_tbl, meter);
+	if (err)
+		goto exit_unlock;
+
 	ovs_unlock();
 
 	/* Build response with the meter_id and stats from
···
 
 static int ovs_meter_cmd_get(struct sk_buff *skb, struct genl_info *info)
 {
-	struct nlattr **a = info->attrs;
-	u32 meter_id;
 	struct ovs_header *ovs_header = info->userhdr;
 	struct ovs_header *ovs_reply_header;
-	struct datapath *dp;
-	int err;
-	struct sk_buff *reply;
+	struct nlattr **a = info->attrs;
 	struct dp_meter *meter;
+	struct sk_buff *reply;
+	struct datapath *dp;
+	u32 meter_id;
+	int err;
 
 	if (!a[OVS_METER_ATTR_ID])
 		return -EINVAL;
···
 	}
 
 	/* Locate meter, copy stats. */
-	meter = lookup_meter(dp, meter_id);
+	meter = lookup_meter(&dp->meter_tbl, meter_id);
 	if (!meter) {
 		err = -ENOENT;
 		goto exit_unlock;
···
 
 static int ovs_meter_cmd_del(struct sk_buff *skb, struct genl_info *info)
 {
-	struct nlattr **a = info->attrs;
-	u32 meter_id;
 	struct ovs_header *ovs_header = info->userhdr;
 	struct ovs_header *ovs_reply_header;
-	struct datapath *dp;
-	int err;
-	struct sk_buff *reply;
+	struct nlattr **a = info->attrs;
 	struct dp_meter *old_meter;
+	struct sk_buff *reply;
+	struct datapath *dp;
+	u32 meter_id;
+	int err;
 
 	if (!a[OVS_METER_ATTR_ID])
 		return -EINVAL;
-	meter_id = nla_get_u32(a[OVS_METER_ATTR_ID]);
 
 	reply = ovs_meter_cmd_reply_start(info, OVS_METER_CMD_DEL,
 					  &ovs_reply_header);
···
 		goto exit_unlock;
 	}
 
-	old_meter = lookup_meter(dp, meter_id);
+	meter_id = nla_get_u32(a[OVS_METER_ATTR_ID]);
+	old_meter = lookup_meter(&dp->meter_tbl, meter_id);
 	if (old_meter) {
 		spin_lock_bh(&old_meter->lock);
 		err = ovs_meter_cmd_reply_stats(reply, meter_id, old_meter);
 		WARN_ON(err);
 		spin_unlock_bh(&old_meter->lock);
-		detach_meter(old_meter);
+
+		err = detach_meter(&dp->meter_tbl, old_meter);
+		if (err)
+			goto exit_unlock;
 	}
+
 	ovs_unlock();
 	ovs_meter_free(old_meter);
 	genlmsg_end(reply, ovs_reply_header);
···
 bool ovs_meter_execute(struct datapath *dp, struct sk_buff *skb,
 		       struct sw_flow_key *key, u32 meter_id)
 {
-	struct dp_meter *meter;
-	struct dp_meter_band *band;
 	long long int now_ms = div_u64(ktime_get_ns(), 1000 * 1000);
 	long long int long_delta_ms;
-	u32 delta_ms;
-	u32 cost;
+	struct dp_meter_band *band;
+	struct dp_meter *meter;
 	int i, band_exceeded_max = -1;
 	u32 band_exceeded_rate = 0;
+	u32 delta_ms;
+	u32 cost;
 
-	meter = lookup_meter(dp, meter_id);
+	meter = lookup_meter(&dp->meter_tbl, meter_id);
 	/* Do not drop the packet when there is no meter. */
 	if (!meter)
 		return false;
···
 
 int ovs_meters_init(struct datapath *dp)
 {
-	int i;
+	struct dp_meter_table *tbl = &dp->meter_tbl;
+	struct dp_meter_instance *ti;
+	unsigned long free_mem_bytes;
 
-	dp->meters = kmalloc_array(METER_HASH_BUCKETS,
-				   sizeof(struct hlist_head), GFP_KERNEL);
-
-	if (!dp->meters)
+	ti = dp_meter_instance_alloc(DP_METER_ARRAY_SIZE_MIN);
+	if (!ti)
 		return -ENOMEM;
 
-	for (i = 0; i < METER_HASH_BUCKETS; i++)
-		INIT_HLIST_HEAD(&dp->meters[i]);
+	/* Allow meters in a datapath to use ~3.12% of physical memory. */
+	free_mem_bytes = nr_free_buffer_pages() * (PAGE_SIZE >> 5);
+	tbl->max_meters_allowed = min(free_mem_bytes / sizeof(struct dp_meter),
+				      DP_METER_NUM_MAX);
+	if (!tbl->max_meters_allowed)
+		goto out_err;
+
+	rcu_assign_pointer(tbl->ti, ti);
+	tbl->count = 0;
 
 	return 0;
+
+out_err:
+	dp_meter_instance_free(ti);
+	return -ENOMEM;
 }
 
 void ovs_meters_exit(struct datapath *dp)
 {
+	struct dp_meter_table *tbl = &dp->meter_tbl;
+	struct dp_meter_instance *ti = rcu_dereference_raw(tbl->ti);
 	int i;
 
-	for (i = 0; i < METER_HASH_BUCKETS; i++) {
-		struct hlist_head *head = &dp->meters[i];
-		struct dp_meter *meter;
-		struct hlist_node *n;
+	for (i = 0; i < ti->n_meters; i++)
+		ovs_meter_free(ti->dp_meters[i]);
 
-		hlist_for_each_entry_safe(meter, n, head, dp_hash_node)
-			kfree(meter);
-	}
-
-	kfree(dp->meters);
+	dp_meter_instance_free(ti);
 }

net/openvswitch/meter.h

···
 #include <linux/openvswitch.h>
 #include <linux/genetlink.h>
 #include <linux/skbuff.h>
+#include <linux/bits.h>
 
 #include "flow.h"
 struct datapath;
 
 #define DP_MAX_BANDS		1
+#define DP_METER_ARRAY_SIZE_MIN	BIT_ULL(10)
+#define DP_METER_NUM_MAX	(200000UL)
 
 struct dp_meter_band {
 	u32 type;
 	u32 rate;
 	u32 burst_size;
-	u32 bucket; /* 1/1000 packets, or in bits */
+	u64 bucket; /* 1/1000 packets, or in bits */
 	struct ovs_flow_stats stats;
 };
 
 struct dp_meter {
 	spinlock_t lock;    /* Per meter lock */
 	struct rcu_head rcu;
-	struct hlist_node dp_hash_node; /*Element in datapath->meters
-					 * hash table.
-					 */
 	u32 id;
 	u16 kbps:1, keep_stats:1;
 	u16 n_bands;
···
 	u64 used;
 	struct ovs_flow_stats stats;
 	struct dp_meter_band bands[];
+};
+
+struct dp_meter_instance {
+	struct rcu_head rcu;
+	u32 n_meters;
+	struct dp_meter __rcu *dp_meters[];
+};
+
+struct dp_meter_table {
+	struct dp_meter_instance __rcu *ti;
+	u32 count;
+	u32 max_meters_allowed;
 };
 
 extern struct genl_family dp_meter_genl_family;