*: Rearrange vrf_bitmap_X api to reduce memory footprint

When running all daemons with config for most of them, FRR has
sharpd@janelle:~/frr$ vtysh -c "show debug hashtable"  | grep "VRF BIT HASH" | wc -l
3570

3570 hashes for bitmaps associated with the vrf.  This is a very
large number of hashes.  Let's do two things:

a) Reduce the created size of the actually created hashes to 2
instead of 32.

b) Delay generation of the hash *until* a set operation happens.
As that no hash directly implies a unset value if/when checked.

This reduces the number of hashes to 61 in my setup for normal
operation.

Signed-off-by: Donald Sharp <sharpd@nvidia.com>

1 files changed, 41 insertions, 15 deletions

diff --git a/lib/vrf.c b/lib/vrf.c
index 73f5d8ff72..b279e8b7bf 100644
--- a/lib/vrf.c
+++ b/lib/vrf.c
@@ -384,54 +384,80 @@ static void vrf_hash_bitmap_free(void *data)
 	XFREE(MTYPE_VRF_BITMAP, bit);
 }
 
-vrf_bitmap_t vrf_bitmap_init(void)
+void vrf_bitmap_init(vrf_bitmap_t *pbmap)
 {
-	return hash_create_size(32, vrf_hash_bitmap_key, vrf_hash_bitmap_cmp,
-				"VRF BIT HASH");
+	*pbmap = NULL;
 }
 
-void vrf_bitmap_free(vrf_bitmap_t bmap)
+void vrf_bitmap_free(vrf_bitmap_t *pbmap)
 {
-	struct hash *vrf_hash = bmap;
+	struct hash *vrf_hash;
+
+	if (!*pbmap)
+		return;
+
+	vrf_hash = *pbmap;
 
 	hash_clean_and_free(&vrf_hash, vrf_hash_bitmap_free);
 }
 
-void vrf_bitmap_set(vrf_bitmap_t bmap, vrf_id_t vrf_id)
+void vrf_bitmap_set(vrf_bitmap_t *pbmap, vrf_id_t vrf_id)
 {
 	struct vrf_bit_set lookup = { .vrf_id = vrf_id };
-	struct hash *vrf_hash = bmap;
+	struct hash *vrf_hash;
 	struct vrf_bit_set *bit;
 
-	if (vrf_hash == NULL || vrf_id == VRF_UNKNOWN)
+	if (vrf_id == VRF_UNKNOWN)
 		return;
 
+	if (!*pbmap)
+		*pbmap = vrf_hash =
+			hash_create_size(2, vrf_hash_bitmap_key,
+					 vrf_hash_bitmap_cmp, "VRF BIT HASH");
+	else
+		vrf_hash = *pbmap;
+
 	bit = hash_get(vrf_hash, &lookup, vrf_hash_bitmap_alloc);
 	bit->set = true;
 }
 
-void vrf_bitmap_unset(vrf_bitmap_t bmap, vrf_id_t vrf_id)
+void vrf_bitmap_unset(vrf_bitmap_t *pbmap, vrf_id_t vrf_id)
 {
 	struct vrf_bit_set lookup = { .vrf_id = vrf_id };
-	struct hash *vrf_hash = bmap;
+	struct hash *vrf_hash;
 	struct vrf_bit_set *bit;
 
-	if (vrf_hash == NULL || vrf_id == VRF_UNKNOWN)
+	if (vrf_id == VRF_UNKNOWN)
+		return;
+
+	/*
+	 * If the hash is not created then unsetting is unnecessary
+	 */
+	if (!*pbmap)
+		return;
+
+	vrf_hash = *pbmap;
+
+	/*
+	 * If we can't look it up, no need to unset it!
+	 */
+	bit = hash_lookup(vrf_hash, &lookup);
+	if (!bit)
 		return;
 
-	bit = hash_get(vrf_hash, &lookup, vrf_hash_bitmap_alloc);
 	bit->set = false;
 }
 
-int vrf_bitmap_check(vrf_bitmap_t bmap, vrf_id_t vrf_id)
+int vrf_bitmap_check(vrf_bitmap_t *pbmap, vrf_id_t vrf_id)
 {
 	struct vrf_bit_set lookup = { .vrf_id = vrf_id };
-	struct hash *vrf_hash = bmap;
+	struct hash *vrf_hash;
 	struct vrf_bit_set *bit;
 
-	if (vrf_hash == NULL || vrf_id == VRF_UNKNOWN)
+	if (!*pbmap || vrf_id == VRF_UNKNOWN)
 		return 0;
 
+	vrf_hash = *pbmap;
 	bit = hash_lookup(vrf_hash, &lookup);
 	if (bit)
 		return bit->set;