[PATCH v5] net/bonding: another fix to LACP mempool size

[Gaoxiang Liu <gaoxiangliu0@163.com>]

The following log message may appear after a slave is idle(or nearly
idle)
for a few minutes:"PMD: Failed to allocate LACP packet from pool".
And bond mode 4 negotiation may fail.

Problem:When bond mode 4 has been chosed and delicated queue has
not been enable, all mbufs from a slave' private pool(used
exclusively for transmitting LACPDUs) have been allocated in
interrupt thread, and are still sitting in the device's tx
descriptor ring and other cores' mempool caches in fwd thread.
Thus the interrupt thread can not alloc LACP packet from pool.

Solution: Ensure that each slave'tx (LACPDU) mempool owns more than
n-tx-queues * n-tx-descriptor + fwd_core_num *
per-core-mmempool-flush-threshold mbufs.

Note that the LACP tx machine fuction is the only code that allocates
from a slave's private pool. It runs in the context of the interrupt
thread, and thus it has no mempool cache of its own.

Signed-off-by: Gaoxiang Liu <liugaoxiang@huawei.com>

---
v2:
* Fixed compile issues.

v3:
* delete duplicate code.

v4;
* Fixed some issues.
1. total_tx_desc should use +=
2. add detailed logs

v5:
* Fixed some issues.
1. move CACHE_FLUSHTHRESH_MULTIPLIER to rte_eth_bond-8023ad.c
2. use RTE_MIN
---
 drivers/net/bonding/rte_eth_bond_8023ad.c | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/drivers/net/bonding/rte_eth_bond_8023ad.c b/drivers/net/bonding/rte_eth_bond_8023ad.c
index ca50583d62..4c65e7fff7 100644
--- a/drivers/net/bonding/rte_eth_bond_8023ad.c
+++ b/drivers/net/bonding/rte_eth_bond_8023ad.c
@@ -1050,6 +1050,7 @@ bond_mode_8023ad_activate_slave(struct rte_eth_dev *bond_dev,
 	uint32_t total_tx_desc;
 	struct bond_tx_queue *bd_tx_q;
 	uint16_t q_id;
+	uint32_t cache_size;
 
 	/* Given slave mus not be in active list */
 	RTE_ASSERT(find_slave_by_id(internals->active_slaves,
@@ -1100,11 +1101,15 @@ bond_mode_8023ad_activate_slave(struct rte_eth_dev *bond_dev,
 		total_tx_desc += bd_tx_q->nb_tx_desc;
 	}
 
+/* 8023AD_CACHE_FLUSHTHRESH_MULTIPLIER  is the same as
+ * CACHE_FLUSHTHRESH_MULTIPLIER already defined in rte_mempool.c */
+#define 8023AD_CACHE_FLUSHTHRESH_MULTIPLIER 1.5
+
+	cache_size = RTE_MIN(RTE_MEMPOOL_CACHE_MAX_SIZE, 32);
+	total_tx_desc += rte_lcore_count() * cache_size * 8023AD_CACHE_FLUSHTHRESH_MULTIPLIER;
 	snprintf(mem_name, RTE_DIM(mem_name), "slave_port%u_pool", slave_id);
 	port->mbuf_pool = rte_pktmbuf_pool_create(mem_name, total_tx_desc,
-		RTE_MEMPOOL_CACHE_MAX_SIZE >= 32 ?
-			32 : RTE_MEMPOOL_CACHE_MAX_SIZE,
-		0, element_size, socket_id);
+		cache_size, 0, element_size, socket_id);
 
 	/* Any memory allocation failure in initialization is critical because
 	 * resources can't be free, so reinitialization is impossible. */
-- 
2.32.0