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[vpp.git] / src / vppinfra / bihash_template.h

diff --git a/src/vppinfra/bihash_template.h b/src/vppinfra/bihash_template.h
index feb6fb6..ea1b6f7 100644 (file)
--- a/src/vppinfra/bihash_template.h
+++ b/src/vppinfra/bihash_template.h
@@ -65,7 +65,9 @@ typedef struct
     };
     u64 as_u64;
   };
+#if BIHASH_KVP_CACHE_SIZE > 0
     BVT (clib_bihash_kv) cache[BIHASH_KVP_CACHE_SIZE];
+#endif
 } BVT (clib_bihash_bucket);
 
 typedef struct
@@ -155,11 +157,16 @@ BV (clib_bihash_update_lru_not_inline) (BVT (clib_bihash_bucket) * b,
 
 static inline u8 BV (clib_bihash_get_lru) (BVT (clib_bihash_bucket) * b)
 {
+#if BIHASH_KVP_CACHE_SIZE > 0
   return (b->cache_lru >> (3 * (BIHASH_KVP_CACHE_SIZE - 1))) & 7;
+#else
+  return 0;
+#endif
 }
 
 static inline void BV (clib_bihash_reset_cache) (BVT (clib_bihash_bucket) * b)
 {
+#if BIHASH_KVP_CACHE_SIZE > 0
   u16 initial_lru_value;
 
   memset (b->cache, 0xff, sizeof (b->cache));
@@ -180,15 +187,32 @@ static inline void BV (clib_bihash_reset_cache) (BVT (clib_bihash_bucket) * b)
     initial_lru_value = (0 << 12) | (1 << 9) | (2 << 6) | (3 << 3) | (4 << 0);
 
   b->cache_lru = initial_lru_value;
+#endif
 }
 
-static inline void BV (clib_bihash_cache_enable_disable)
-  (BVT (clib_bihash_bucket) * b, u8 enable)
+static inline int BV (clib_bihash_lock_bucket) (BVT (clib_bihash_bucket) * b)
 {
   BVT (clib_bihash_bucket) tmp_b;
+  u64 rv;
+
+  tmp_b.as_u64 = 0;
+  tmp_b.cache_lru = 1 << 15;
+
+  rv = __sync_fetch_and_or (&b->as_u64, tmp_b.as_u64);
+  tmp_b.as_u64 = rv;
+  /* Was already locked? */
+  if (tmp_b.cache_lru & (1 << 15))
+    return 0;
+  return 1;
+}
+
+static inline void BV (clib_bihash_unlock_bucket)
+  (BVT (clib_bihash_bucket) * b)
+{
+  BVT (clib_bihash_bucket) tmp_b;
+
   tmp_b.as_u64 = b->as_u64;
-  tmp_b.cache_lru &= 0x7FFF;
-  tmp_b.cache_lru |= enable << 15;
+  tmp_b.cache_lru &= ~(1 << 15);
   b->as_u64 = tmp_b.as_u64;
 }
 
@@ -238,7 +262,9 @@ static inline int BV (clib_bihash_search_inline)
   u32 bucket_index;
   BVT (clib_bihash_value) * v;
   BVT (clib_bihash_bucket) * b;
+#if BIHASH_KVP_CACHE_SIZE > 0
   BVT (clib_bihash_kv) * kvp;
+#endif
   int i, limit;
 
   hash = BV (clib_bihash_hash) (key_result);
@@ -249,8 +275,9 @@ static inline int BV (clib_bihash_search_inline)
   if (b->offset == 0)
     return -1;
 
-  /* Check the cache, if currently enabled */
-  if (PREDICT_TRUE (b->cache_lru & (1 << 15)))
+#if BIHASH_KVP_CACHE_SIZE > 0
+  /* Check the cache, if not currently locked */
+  if (PREDICT_TRUE ((b->cache_lru & (1 << 15)) == 0))
     {
       limit = BIHASH_KVP_CACHE_SIZE;
       kvp = b->cache;
@@ -264,6 +291,7 @@ static inline int BV (clib_bihash_search_inline)
            }
        }
     }
+#endif
 
   hash >>= h->log2_nbuckets;
 
@@ -279,20 +307,22 @@ static inline int BV (clib_bihash_search_inline)
     {
       if (BV (clib_bihash_key_compare) (v->kvp[i].key, key_result->key))
        {
-         u8 cache_slot;
          *key_result = v->kvp[i];
 
-         /* Shut off the cache */
-         BV (clib_bihash_cache_enable_disable) (b, 0);
-         CLIB_MEMORY_BARRIER ();
-
-         cache_slot = BV (clib_bihash_get_lru) (b);
-         b->cache[cache_slot] = v->kvp[i];
-         BV (clib_bihash_update_lru) (b, cache_slot);
+#if BIHASH_KVP_CACHE_SIZE > 0
+         u8 cache_slot;
+         /* Try to lock the bucket */
+         if (BV (clib_bihash_lock_bucket) (b))
+           {
+             cache_slot = BV (clib_bihash_get_lru) (b);
+             b->cache[cache_slot] = v->kvp[i];
+             BV (clib_bihash_update_lru) (b, cache_slot);
 
-         /* Reenable the cache */
-         BV (clib_bihash_cache_enable_disable) (b, 1);
-         h->cache_misses++;
+             /* Unlock the bucket */
+             BV (clib_bihash_unlock_bucket) (b);
+             h->cache_misses++;
+           }
+#endif
          return 0;
        }
     }
@@ -307,7 +337,9 @@ static inline int BV (clib_bihash_search_inline_2)
   u32 bucket_index;
   BVT (clib_bihash_value) * v;
   BVT (clib_bihash_bucket) * b;
+#if BIHASH_KVP_CACHE_SIZE > 0
   BVT (clib_bihash_kv) * kvp;
+#endif
   int i, limit;
 
   ASSERT (valuep);
@@ -320,8 +352,9 @@ static inline int BV (clib_bihash_search_inline_2)
   if (b->offset == 0)
     return -1;
 
-  /* Check the cache, if currently enabled */
-  if (PREDICT_TRUE (b->cache_lru & (1 << 15)))
+  /* Check the cache, if currently unlocked */
+#if BIHASH_KVP_CACHE_SIZE > 0
+  if (PREDICT_TRUE ((b->cache_lru & (1 << 15)) == 0))
     {
       limit = BIHASH_KVP_CACHE_SIZE;
       kvp = b->cache;
@@ -335,6 +368,7 @@ static inline int BV (clib_bihash_search_inline_2)
            }
        }
     }
+#endif
 
   hash >>= h->log2_nbuckets;
   v = BV (clib_bihash_get_value) (h, b->offset);
@@ -349,20 +383,23 @@ static inline int BV (clib_bihash_search_inline_2)
     {
       if (BV (clib_bihash_key_compare) (v->kvp[i].key, search_key->key))
        {
-         u8 cache_slot;
          *valuep = v->kvp[i];
 
-         /* Shut off the cache */
-         BV (clib_bihash_cache_enable_disable) (b, 0);
-         CLIB_MEMORY_BARRIER ();
+#if BIHASH_KVP_CACHE_SIZE > 0
+         u8 cache_slot;
 
-         cache_slot = BV (clib_bihash_get_lru) (b);
-         b->cache[cache_slot] = v->kvp[i];
-         BV (clib_bihash_update_lru) (b, cache_slot);
+         /* Try to lock the bucket */
+         if (BV (clib_bihash_lock_bucket) (b))
+           {
+             cache_slot = BV (clib_bihash_get_lru) (b);
+             b->cache[cache_slot] = v->kvp[i];
+             BV (clib_bihash_update_lru) (b, cache_slot);
 
-         /* Reenable the cache */
-         BV (clib_bihash_cache_enable_disable) (b, 1);
-         h->cache_misses++;
+             /* Reenable the cache */
+             BV (clib_bihash_unlock_bucket) (b);
+             h->cache_misses++;
+           }
+#endif
          return 0;
        }
     }