[ovs-dev] [PATCH net-next v2 2/2] net: openvswitch: make masks cache size configurable
Eelco Chaudron
echaudro at redhat.com
Thu Jul 23 12:58:31 UTC 2020
This patch makes the masks cache size configurable, or with
a size of 0, disable it.
Reviewed-by: Paolo Abeni <pabeni at redhat.com>
Signed-off-by: Eelco Chaudron <echaudro at redhat.com>
---
include/uapi/linux/openvswitch.h | 1
net/openvswitch/datapath.c | 14 ++++++
net/openvswitch/flow_table.c | 90 ++++++++++++++++++++++++++++++++++----
net/openvswitch/flow_table.h | 10 ++++
4 files changed, 104 insertions(+), 11 deletions(-)
diff --git a/include/uapi/linux/openvswitch.h b/include/uapi/linux/openvswitch.h
index 7cb76e5ca7cf..8300cc29dec8 100644
--- a/include/uapi/linux/openvswitch.h
+++ b/include/uapi/linux/openvswitch.h
@@ -86,6 +86,7 @@ enum ovs_datapath_attr {
OVS_DP_ATTR_MEGAFLOW_STATS, /* struct ovs_dp_megaflow_stats */
OVS_DP_ATTR_USER_FEATURES, /* OVS_DP_F_* */
OVS_DP_ATTR_PAD,
+ OVS_DP_ATTR_MASKS_CACHE_SIZE,
__OVS_DP_ATTR_MAX
};
diff --git a/net/openvswitch/datapath.c b/net/openvswitch/datapath.c
index a54df1fe3ec4..114b2ddb8037 100644
--- a/net/openvswitch/datapath.c
+++ b/net/openvswitch/datapath.c
@@ -1498,6 +1498,7 @@ static size_t ovs_dp_cmd_msg_size(void)
msgsize += nla_total_size_64bit(sizeof(struct ovs_dp_stats));
msgsize += nla_total_size_64bit(sizeof(struct ovs_dp_megaflow_stats));
msgsize += nla_total_size(sizeof(u32)); /* OVS_DP_ATTR_USER_FEATURES */
+ msgsize += nla_total_size(sizeof(u32)); /* OVS_DP_ATTR_MASKS_CACHE_SIZE */
return msgsize;
}
@@ -1535,6 +1536,10 @@ static int ovs_dp_cmd_fill_info(struct datapath *dp, struct sk_buff *skb,
if (nla_put_u32(skb, OVS_DP_ATTR_USER_FEATURES, dp->user_features))
goto nla_put_failure;
+ if (nla_put_u32(skb, OVS_DP_ATTR_MASKS_CACHE_SIZE,
+ ovs_flow_tbl_masks_cache_size(&dp->table)))
+ goto nla_put_failure;
+
genlmsg_end(skb, ovs_header);
return 0;
@@ -1599,6 +1604,13 @@ static int ovs_dp_change(struct datapath *dp, struct nlattr *a[])
#endif
}
+ if (a[OVS_DP_ATTR_MASKS_CACHE_SIZE]) {
+ u32 cache_size;
+
+ cache_size = nla_get_u32(a[OVS_DP_ATTR_MASKS_CACHE_SIZE]);
+ ovs_flow_tbl_masks_cache_resize(&dp->table, cache_size);
+ }
+
dp->user_features = user_features;
if (dp->user_features & OVS_DP_F_TC_RECIRC_SHARING)
@@ -1894,6 +1906,8 @@ static const struct nla_policy datapath_policy[OVS_DP_ATTR_MAX + 1] = {
[OVS_DP_ATTR_NAME] = { .type = NLA_NUL_STRING, .len = IFNAMSIZ - 1 },
[OVS_DP_ATTR_UPCALL_PID] = { .type = NLA_U32 },
[OVS_DP_ATTR_USER_FEATURES] = { .type = NLA_U32 },
+ [OVS_DP_ATTR_MASKS_CACHE_SIZE] = NLA_POLICY_RANGE(NLA_U32, 0,
+ PCPU_MIN_UNIT_SIZE / sizeof(struct mask_cache_entry)),
};
static const struct genl_ops dp_datapath_genl_ops[] = {
diff --git a/net/openvswitch/flow_table.c b/net/openvswitch/flow_table.c
index a5912ea05352..386b7e7a0454 100644
--- a/net/openvswitch/flow_table.c
+++ b/net/openvswitch/flow_table.c
@@ -38,8 +38,8 @@
#define MASK_ARRAY_SIZE_MIN 16
#define REHASH_INTERVAL (10 * 60 * HZ)
+#define MC_DEFAULT_HASH_ENTRIES 256
#define MC_HASH_SHIFT 8
-#define MC_HASH_ENTRIES (1u << MC_HASH_SHIFT)
#define MC_HASH_SEGS ((sizeof(uint32_t) * 8) / MC_HASH_SHIFT)
static struct kmem_cache *flow_cache;
@@ -341,15 +341,76 @@ static void flow_mask_remove(struct flow_table *tbl, struct sw_flow_mask *mask)
}
}
+static void __mask_cache_destroy(struct mask_cache *mc)
+{
+ if (mc->mask_cache)
+ free_percpu(mc->mask_cache);
+ kfree(mc);
+}
+
+static void mask_cache_rcu_cb(struct rcu_head *rcu)
+{
+ struct mask_cache *mc = container_of(rcu, struct mask_cache, rcu);
+
+ __mask_cache_destroy(mc);
+}
+
+static struct mask_cache *tbl_mask_cache_alloc(u32 size)
+{
+ struct mask_cache_entry __percpu *cache = NULL;
+ struct mask_cache *new;
+
+ /* Only allow size to be 0, or a power of 2, and does not exceed
+ * percpu allocation size.
+ */
+ if ((size & (size - 1)) != 0 ||
+ (size * sizeof(struct mask_cache_entry)) > PCPU_MIN_UNIT_SIZE)
+ return NULL;
+
+ new = kzalloc(sizeof(*new), GFP_KERNEL);
+ if (!new)
+ return NULL;
+
+ new->cache_size = size;
+ if (new->cache_size > 0) {
+ cache = __alloc_percpu(sizeof(struct mask_cache_entry) *
+ new->cache_size,
+ __alignof__(struct mask_cache_entry));
+
+ if (!cache) {
+ kfree(new);
+ return NULL;
+ }
+ }
+
+ new->mask_cache = cache;
+ return new;
+}
+
+void ovs_flow_tbl_masks_cache_resize(struct flow_table *table, u32 size)
+{
+ struct mask_cache *mc = rcu_dereference(table->mask_cache);
+ struct mask_cache *new;
+
+ if (size == mc->cache_size || (size & (size - 1)) != 0)
+ return;
+
+ new = tbl_mask_cache_alloc(size);
+ if (!new)
+ return;
+
+ rcu_assign_pointer(table->mask_cache, new);
+ call_rcu(&mc->rcu, mask_cache_rcu_cb);
+}
+
int ovs_flow_tbl_init(struct flow_table *table)
{
struct table_instance *ti, *ufid_ti;
+ struct mask_cache *mc;
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)
+ mc = tbl_mask_cache_alloc(MC_DEFAULT_HASH_ENTRIES);
+ if (!mc)
return -ENOMEM;
ma = tbl_mask_array_alloc(MASK_ARRAY_SIZE_MIN);
@@ -367,6 +428,7 @@ int ovs_flow_tbl_init(struct flow_table *table)
rcu_assign_pointer(table->ti, ti);
rcu_assign_pointer(table->ufid_ti, ufid_ti);
rcu_assign_pointer(table->mask_array, ma);
+ rcu_assign_pointer(table->mask_cache, mc);
table->last_rehash = jiffies;
table->count = 0;
table->ufid_count = 0;
@@ -377,7 +439,7 @@ int ovs_flow_tbl_init(struct flow_table *table)
free_mask_array:
__mask_array_destroy(ma);
free_mask_cache:
- free_percpu(table->mask_cache);
+ __mask_cache_destroy(mc);
return -ENOMEM;
}
@@ -454,7 +516,7 @@ void ovs_flow_tbl_destroy(struct flow_table *table)
struct table_instance *ti = rcu_dereference_raw(table->ti);
struct table_instance *ufid_ti = rcu_dereference_raw(table->ufid_ti);
- free_percpu(table->mask_cache);
+ call_rcu(&table->mask_cache->rcu, mask_cache_rcu_cb);
call_rcu(&table->mask_array->rcu, mask_array_rcu_cb);
table_instance_destroy(table, ti, ufid_ti, false);
}
@@ -724,6 +786,7 @@ struct sw_flow *ovs_flow_tbl_lookup_stats(struct flow_table *tbl,
u32 *n_mask_hit,
u32 *n_cache_hit)
{
+ struct mask_cache *mc = rcu_dereference(tbl->mask_cache);
struct mask_array *ma = rcu_dereference(tbl->mask_array);
struct table_instance *ti = rcu_dereference(tbl->ti);
struct mask_cache_entry *entries, *ce;
@@ -733,7 +796,7 @@ struct sw_flow *ovs_flow_tbl_lookup_stats(struct flow_table *tbl,
*n_mask_hit = 0;
*n_cache_hit = 0;
- if (unlikely(!skb_hash)) {
+ if (unlikely(!skb_hash || mc->cache_size == 0)) {
u32 mask_index = 0;
u32 cache = 0;
@@ -749,11 +812,11 @@ struct sw_flow *ovs_flow_tbl_lookup_stats(struct flow_table *tbl,
ce = NULL;
hash = skb_hash;
- entries = this_cpu_ptr(tbl->mask_cache);
+ entries = this_cpu_ptr(mc->mask_cache);
/* Find the cache entry 'ce' to operate on. */
for (seg = 0; seg < MC_HASH_SEGS; seg++) {
- int index = hash & (MC_HASH_ENTRIES - 1);
+ int index = hash & (mc->cache_size - 1);
struct mask_cache_entry *e;
e = &entries[index];
@@ -867,6 +930,13 @@ int ovs_flow_tbl_num_masks(const struct flow_table *table)
return READ_ONCE(ma->count);
}
+u32 ovs_flow_tbl_masks_cache_size(const struct flow_table *table)
+{
+ struct mask_cache *mc = rcu_dereference(table->mask_cache);
+
+ return READ_ONCE(mc->cache_size);
+}
+
static struct table_instance *table_instance_expand(struct table_instance *ti,
bool ufid)
{
diff --git a/net/openvswitch/flow_table.h b/net/openvswitch/flow_table.h
index 325e939371d8..f2dba952db2f 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_cache {
+ struct rcu_head rcu;
+ u32 cache_size; /* Must be ^2 value. */
+ struct mask_cache_entry __percpu *mask_cache;
+};
+
struct mask_count {
int index;
u64 counter;
@@ -53,7 +59,7 @@ struct table_instance {
struct flow_table {
struct table_instance __rcu *ti;
struct table_instance __rcu *ufid_ti;
- struct mask_cache_entry __percpu *mask_cache;
+ struct mask_cache __rcu *mask_cache;
struct mask_array __rcu *mask_array;
unsigned long last_rehash;
unsigned int count;
@@ -77,6 +83,8 @@ int ovs_flow_tbl_insert(struct flow_table *table, struct sw_flow *flow,
const struct sw_flow_mask *mask);
void ovs_flow_tbl_remove(struct flow_table *table, struct sw_flow *flow);
int ovs_flow_tbl_num_masks(const struct flow_table *table);
+u32 ovs_flow_tbl_masks_cache_size(const struct flow_table *table);
+void ovs_flow_tbl_masks_cache_resize(struct flow_table *table, u32 size);
struct sw_flow *ovs_flow_tbl_dump_next(struct table_instance *table,
u32 *bucket, u32 *idx);
struct sw_flow *ovs_flow_tbl_lookup_stats(struct flow_table *,
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