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Atomic bucket lock

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Change-Id: I84908b9ad30d7555024e98b69ed37b111f31c27a
Signed-off-by: Dave Barach <dbarach@cisco.com>
This commit is contained in:
Dave Barach
2017-07-21 10:44:27 -04:00
committed by John Lo
parent 6534b7aa13
commit 858c06fac6
2 changed files with 58 additions and 41 deletions
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27
src/vppinfra/bihash_template.c
View File

@ -135,8 +135,9 @@ BV (make_working_copy) (BVT (clib_bihash) * h, BVT (clib_bihash_bucket) * b)
clib_mem_set_heap (oldheap);
/* Turn off the cache */
BV (clib_bihash_cache_enable_disable) (b, 0);
/* Lock the bucket... */
while (BV (clib_bihash_lock_bucket) (b) == 0)
;
v = BV (clib_bihash_get_value) (h, b->offset);
@ -416,7 +417,7 @@ expand_ok:
unlock:
BV (clib_bihash_reset_cache) (b);
BV (clib_bihash_cache_enable_disable) (b, 1 /* enable */ );
BV (clib_bihash_unlock_bucket) (b);
CLIB_MEMORY_BARRIER ();
h->writer_lock[0] = 0;
return rv;
@ -444,7 +445,7 @@ int BV (clib_bihash_search)
return -1;
/* Check the cache, if currently enabled */
if (PREDICT_TRUE (b->cache_lru & (1 << 15)))
if (PREDICT_TRUE ((b->cache_lru & (1 << 15)) == 0))
{
limit = BIHASH_KVP_CACHE_SIZE;
kvp = b->cache;
@ -475,16 +476,16 @@ int BV (clib_bihash_search)
*valuep = v->kvp[i];
/* Shut off the cache */
BV (clib_bihash_cache_enable_disable) (b, 0);
CLIB_MEMORY_BARRIER ();
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);
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++;
}
return 0;
}
}

72
src/vppinfra/bihash_template.h
View File

@ -182,13 +182,29 @@ static inline void BV (clib_bihash_reset_cache) (BVT (clib_bihash_bucket) * b)
b->cache_lru = initial_lru_value;
}
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;
}
@ -249,8 +265,8 @@ 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)))
/* Check the cache, if not currently locked */
if (PREDICT_TRUE ((b->cache_lru & (1 << 15)) == 0))
{
limit = BIHASH_KVP_CACHE_SIZE;
kvp = b->cache;
@ -282,17 +298,17 @@ static inline int BV (clib_bihash_search_inline)
u8 cache_slot;
*key_result = v->kvp[i];
/* Shut off the cache */
BV (clib_bihash_cache_enable_disable) (b, 0);
CLIB_MEMORY_BARRIER ();
/* 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);
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++;
}
return 0;
}
}
@ -320,8 +336,8 @@ 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 (PREDICT_TRUE ((b->cache_lru & (1 << 15)) == 0))
{
limit = BIHASH_KVP_CACHE_SIZE;
kvp = b->cache;
@ -352,17 +368,17 @@ static inline int BV (clib_bihash_search_inline_2)
u8 cache_slot;
*valuep = v->kvp[i];
/* Shut off the cache */
BV (clib_bihash_cache_enable_disable) (b, 0);
CLIB_MEMORY_BARRIER ();
/* 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);
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++;
}
return 0;
}
}