RW concurrency is required with single writer and multiple reader
usecase as well. Hence, multi-writer should not be enabled by default when
RW concurrency is enabled.
Fixes: f2e3001b53ec ("hash: support read/write concurrency")
Cc: yipeng1.w...@intel.com
Signed-off-by: Honnappa Nagarahalli <honnappa.nagaraha...@arm.com>
Reviewed-by: Gavin Hu <gavin...@arm.com>
---
lib/librte_hash/rte_cuckoo_hash.c | 27 ++++++++++++++++-----------
lib/librte_hash/rte_cuckoo_hash.h | 2 ++
test/test/test_hash_readwrite.c | 6 ++++--
3 files changed, 22 insertions(+), 13 deletions(-)
diff --git a/lib/librte_hash/rte_cuckoo_hash.c
b/lib/librte_hash/rte_cuckoo_hash.c
index f7b86c8..e32b746 100644
--- a/lib/librte_hash/rte_cuckoo_hash.c
+++ b/lib/librte_hash/rte_cuckoo_hash.c
@@ -93,6 +93,7 @@ rte_hash_create(const struct rte_hash_parameters *params)
unsigned i;
unsigned int hw_trans_mem_support = 0, multi_writer_support = 0;
unsigned int readwrite_concur_support = 0;
+ unsigned int writer_takes_lock = 0;
rte_hash_function default_hash_func = (rte_hash_function)rte_jhash;
@@ -116,12 +117,14 @@ rte_hash_create(const struct rte_hash_parameters *params)
if (params->extra_flag & RTE_HASH_EXTRA_FLAGS_TRANS_MEM_SUPPORT)
hw_trans_mem_support = 1;
- if (params->extra_flag & RTE_HASH_EXTRA_FLAGS_MULTI_WRITER_ADD)
+ if (params->extra_flag & RTE_HASH_EXTRA_FLAGS_MULTI_WRITER_ADD) {
multi_writer_support = 1;
+ writer_takes_lock = 1;
+ }
if (params->extra_flag & RTE_HASH_EXTRA_FLAGS_RW_CONCURRENCY) {
readwrite_concur_support = 1;
- multi_writer_support = 1;
+ writer_takes_lock = 1;
}
/* Store all keys and leave the first entry as a dummy entry for
lookup_bulk */
@@ -269,6 +272,7 @@ rte_hash_create(const struct rte_hash_parameters *params)
h->hw_trans_mem_support = hw_trans_mem_support;
h->multi_writer_support = multi_writer_support;
h->readwrite_concur_support = readwrite_concur_support;
+ h->writer_takes_lock = writer_takes_lock;
#if defined(RTE_ARCH_X86)
if (rte_cpu_get_flag_enabled(RTE_CPUFLAG_AVX2))
@@ -279,10 +283,11 @@ rte_hash_create(const struct rte_hash_parameters *params)
#endif
h->sig_cmp_fn = RTE_HASH_COMPARE_SCALAR;
- /* Turn on multi-writer only with explicit flag from user and TM
- * support.
+ /* Writer threads need to take the lock when:
+ * 1) RTE_HASH_EXTRA_FLAGS_RW_CONCURRENCY is enabled OR
+ * 2) RTE_HASH_EXTRA_FLAGS_MULTI_WRITER_ADD is enabled
*/
- if (h->multi_writer_support) {
+ if (h->writer_takes_lock) {
h->readwrite_lock = rte_malloc(NULL, sizeof(rte_rwlock_t),
RTE_CACHE_LINE_SIZE);
if (h->readwrite_lock == NULL)
@@ -339,10 +344,10 @@ rte_hash_free(struct rte_hash *h)
rte_rwlock_write_unlock(RTE_EAL_TAILQ_RWLOCK);
- if (h->multi_writer_support) {
+ if (h->multi_writer_support)
rte_free(h->local_free_slots);
+ if (h->writer_takes_lock)
rte_free(h->readwrite_lock);
- }
rte_ring_free(h->free_slots);
rte_free(h->key_store);
rte_free(h->buckets);
@@ -397,9 +402,9 @@ rte_hash_count(const struct rte_hash *h)
static inline void
__hash_rw_writer_lock(const struct rte_hash *h)
{
- if (h->multi_writer_support && h->hw_trans_mem_support)
+ if (h->writer_takes_lock && h->hw_trans_mem_support)
rte_rwlock_write_lock_tm(h->readwrite_lock);
- else if (h->multi_writer_support)
+ else if (h->writer_takes_lock)
rte_rwlock_write_lock(h->readwrite_lock);
}
@@ -416,9 +421,9 @@ __hash_rw_reader_lock(const struct rte_hash *h)
static inline void
__hash_rw_writer_unlock(const struct rte_hash *h)
{
- if (h->multi_writer_support && h->hw_trans_mem_support)
+ if (h->writer_takes_lock && h->hw_trans_mem_support)
rte_rwlock_write_unlock_tm(h->readwrite_lock);
- else if (h->multi_writer_support)
+ else if (h->writer_takes_lock)
rte_rwlock_write_unlock(h->readwrite_lock);
}
diff --git a/lib/librte_hash/rte_cuckoo_hash.h
b/lib/librte_hash/rte_cuckoo_hash.h
index b43f467..6fa429e 100644
--- a/lib/librte_hash/rte_cuckoo_hash.h
+++ b/lib/librte_hash/rte_cuckoo_hash.h
@@ -168,6 +168,8 @@ struct rte_hash {
/**< If multi-writer support is enabled. */
uint8_t readwrite_concur_support;
/**< If read-write concurrency support is enabled */
+ uint8_t writer_takes_lock;
+ /**< Indicates if the writer threads need to take lock */
rte_hash_function hash_func; /**< Function used to calculate hash. */
uint32_t hash_func_init_val; /**< Init value used by hash_func. */
rte_hash_cmp_eq_t rte_hash_custom_cmp_eq;
diff --git a/test/test/test_hash_readwrite.c b/test/test/test_hash_readwrite.c
index 55ae33d..af57708 100644
--- a/test/test/test_hash_readwrite.c
+++ b/test/test/test_hash_readwrite.c
@@ -118,10 +118,12 @@ init_params(int use_htm, int use_jhash)
if (use_htm)
hash_params.extra_flag =
RTE_HASH_EXTRA_FLAGS_TRANS_MEM_SUPPORT |
- RTE_HASH_EXTRA_FLAGS_RW_CONCURRENCY;
+ RTE_HASH_EXTRA_FLAGS_RW_CONCURRENCY |
+ RTE_HASH_EXTRA_FLAGS_MULTI_WRITER_ADD;
else
hash_params.extra_flag =
- RTE_HASH_EXTRA_FLAGS_RW_CONCURRENCY;
+ RTE_HASH_EXTRA_FLAGS_RW_CONCURRENCY |
+ RTE_HASH_EXTRA_FLAGS_MULTI_WRITER_ADD;
hash_params.name = "tests";
--
2.7.4
