net: openvswitch: expand the meters supported number

In kernel datapath of Open vSwitch, there are only 1024
buckets of meter in one datapath. If installing more than
1024 (e.g. 8192) meters, it may lead to the performance drop.
But in some case, for example, Open vSwitch used as edge
gateway, there should be 20K at least, where meters used for
IP address bandwidth limitation.

[Open vSwitch userspace datapath has this issue too.]

For more scalable meter, this patch use meter array instead of
hash tables, and expand/shrink the array when necessary. So we
can install more meters than before in the datapath.
Introducing the struct *dp_meter_instance, it's easy to
expand meter though changing the *ti point in the struct
*dp_meter_table.

Cc: Pravin B Shelar <pshelar@ovn.org>
Cc: Andy Zhou <azhou@ovn.org>
Signed-off-by: Tonghao Zhang <xiangxia.m.yue@gmail.com>
Acked-by: Pravin B Shelar <pshelar@ovn.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 13 insertions, 3 deletions

diff --git a/net/openvswitch/meter.h b/net/openvswitch/meter.h
index f645913870bd..f52052d30a16 100644
--- a/net/openvswitch/meter.h
+++ b/net/openvswitch/meter.h
@@ -13,11 +13,13 @@
 #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)
 
 struct dp_meter_band {
 	u32 type;
@@ -30,9 +32,6 @@ struct dp_meter_band {
 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;
@@ -42,6 +41,17 @@ struct dp_meter {
 	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;
+};
+
 extern struct genl_family dp_meter_genl_family;
 int ovs_meters_init(struct datapath *dp);
 void ovs_meters_exit(struct datapath *dp);