From: Tonghao Zhang <xiangxia.m....@gmail.com>
The full looking up on flow table traverses all mask array.
If mask-array is too large, the number of invalid flow-mask
increase, performance will be drop.
This patch optimizes mask-array operation:
* Inserting, insert it [ma->count- 1] directly.
* Removing, only change last and current mask point, and free current mask.
* Looking up, full looking up will break if mask is NULL.
The function which changes or gets *count* of struct mask_array,
is protected by ovs_lock, but flow_lookup (not protected) should use *max* of
struct mask_array.
Functions protected by ovs_lock:
* tbl_mask_array_del_mask
* tbl_mask_array_add_mask
* flow_mask_find
* ovs_flow_tbl_lookup_exact
* ovs_flow_tbl_num_masks
Signed-off-by: Tonghao Zhang <xiangxia.m....@gmail.com>
---
net/openvswitch/flow_table.c | 106 ++++++++++++++++++++++---------------------
1 file changed, 54 insertions(+), 52 deletions(-)
diff --git a/net/openvswitch/flow_table.c b/net/openvswitch/flow_table.c
index 4c82960..7edddd9 100644
--- a/net/openvswitch/flow_table.c
+++ b/net/openvswitch/flow_table.c
@@ -538,7 +538,7 @@ static struct sw_flow *flow_lookup(struct flow_table *tbl,
mask = rcu_dereference_ovsl(ma->masks[i]);
if (!mask)
- continue;
+ break;
flow = masked_flow_lookup(ti, key, mask, n_mask_hit);
if (flow) { /* Found */
@@ -632,15 +632,13 @@ struct sw_flow *ovs_flow_tbl_lookup_exact(struct
flow_table *tbl,
int i;
/* Always called under ovs-mutex. */
- for (i = 0; i < ma->max; i++) {
+ for (i = 0; i < ma->count; 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) &&
@@ -704,21 +702,34 @@ static struct table_instance
*table_instance_expand(struct table_instance *ti,
return table_instance_rehash(ti, ti->n_buckets * 2, ufid);
}
-static void tbl_mask_array_delete_mask(struct mask_array *ma,
- struct sw_flow_mask *mask)
+static void tbl_mask_array_del_mask(struct flow_table *tbl,
+ struct sw_flow_mask *mask)
{
+ struct mask_array *ma = ovsl_dereference(tbl->mask_array);
int i;
/* Remove the deleted mask pointers from the 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;
- }
+ for (i = 0; i < ma->count; i++) {
+ if (mask == ovsl_dereference(ma->masks[i]))
+ goto found;
}
+
BUG();
+ return;
+
+found:
+ ma->count--;
+ smp_wmb();
+
+ rcu_assign_pointer(ma->masks[i], ma->masks[ma->count]);
+ RCU_INIT_POINTER(ma->masks[ma->count], NULL);
+
+ kfree_rcu(mask, rcu);
+
+ /* Shrink the mask array if necessary. */
+ if (ma->max >= (MASK_ARRAY_SIZE_MIN * 2) &&
+ ma->count <= (ma->max / 3))
+ tbl_mask_array_realloc(tbl, ma->max / 2);
}
/* Remove 'mask' from the mask list, if it is not needed any more. */
@@ -732,17 +743,8 @@ static void flow_mask_remove(struct flow_table *tbl,
struct sw_flow_mask *mask)
BUG_ON(!mask->ref_count);
mask->ref_count--;
- if (!mask->ref_count) {
- struct mask_array *ma;
-
- ma = ovsl_dereference(tbl->mask_array);
- tbl_mask_array_delete_mask(ma, mask);
-
- /* Shrink the mask array if necessary. */
- if (ma->max >= (MASK_ARRAY_SIZE_MIN * 2) &&
- ma->count <= (ma->max / 3))
- tbl_mask_array_realloc(tbl, ma->max / 2);
- }
+ if (!mask->ref_count)
+ tbl_mask_array_del_mask(tbl, mask);
}
}
@@ -795,17 +797,40 @@ static struct sw_flow_mask *flow_mask_find(const struct
flow_table *tbl,
int i;
ma = ovsl_dereference(tbl->mask_array);
- for (i = 0; i < ma->max; i++) {
+ for (i = 0; i < ma->count; i++) {
struct sw_flow_mask *t;
t = ovsl_dereference(ma->masks[i]);
- if (t && mask_equal(mask, t))
+ if (mask_equal(mask, t))
return t;
}
return NULL;
}
+static int tbl_mask_array_add_mask(struct flow_table *tbl,
+ struct sw_flow_mask *new)
+{
+ struct mask_array *ma = ovsl_dereference(tbl->mask_array);
+ int err;
+
+ if (ma->count >= ma->max) {
+ err = tbl_mask_array_realloc(tbl, ma->max +
+ MASK_ARRAY_SIZE_MIN);
+ if (err)
+ return err;
+ }
+
+ BUG_ON(ovsl_dereference(ma->masks[ma->count]));
+
+ rcu_assign_pointer(ma->masks[ma->count], new);
+
+ smp_wmb();
+ ma->count++;
+
+ return 0;
+}
+
/* Add 'mask' into the mask list, if it is not already there. */
static int flow_mask_insert(struct flow_table *tbl, struct sw_flow *flow,
const struct sw_flow_mask *new)
@@ -814,9 +839,6 @@ static int flow_mask_insert(struct flow_table *tbl, struct
sw_flow *flow,
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)
@@ -825,29 +847,9 @@ static int flow_mask_insert(struct flow_table *tbl, struct
sw_flow *flow,
mask->range = new->range;
/* 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;
- }
+ if (tbl_mask_array_add_mask(tbl, mask)) {
+ kfree(mask);
+ return -ENOMEM;
}
} else {
BUG_ON(!mask->ref_count);
--
1.8.3.1
