[dpdk-dev] [PATCH 3/4] net/bonding: another fix to LACP mempool size

[Robert Sanford]

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".

Problem: All mbufs from a slave's private pool (used exclusively for
transmitting LACPDUs) have been allocated and are still sitting in
the device's tx descriptor ring and other cores' mempool caches.

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

Note that the LACP tx machine function 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: Robert Sanford <rsanford at akamai.com>
---
 drivers/net/bonding/rte_eth_bond_8023ad.c |   10 +++++++---
 1 files changed, 7 insertions(+), 3 deletions(-)

diff --git a/drivers/net/bonding/rte_eth_bond_8023ad.c b/drivers/net/bonding/rte_eth_bond_8023ad.c
index 2f7ae70..1207896 100644
--- a/drivers/net/bonding/rte_eth_bond_8023ad.c
+++ b/drivers/net/bonding/rte_eth_bond_8023ad.c
@@ -854,6 +854,8 @@ bond_mode_8023ad_activate_slave(struct rte_eth_dev *bond_dev, uint8_t slave_id)
 	char mem_name[RTE_ETH_NAME_MAX_LEN];
 	int socket_id;
 	unsigned element_size;
+	unsigned cache_size;
+	unsigned cache_flushthresh;
 	uint32_t total_tx_desc;
 	struct bond_tx_queue *bd_tx_q;
 	uint16_t q_id;
@@ -890,19 +892,21 @@ bond_mode_8023ad_activate_slave(struct rte_eth_dev *bond_dev, uint8_t slave_id)
 
 	element_size = sizeof(struct slow_protocol_frame) + sizeof(struct rte_mbuf)
 				+ RTE_PKTMBUF_HEADROOM;
+	cache_size = RTE_MEMPOOL_CACHE_MAX_SIZE >= 32 ?
+		32 : RTE_MEMPOOL_CACHE_MAX_SIZE;
+	cache_flushthresh = RTE_MEMPOOL_CALC_CACHE_FLUSHTHRESH(cache_size);
 
 	/* The size of the mempool should be at least:
 	 * the sum of the TX descriptors + BOND_MODE_8023AX_SLAVE_TX_PKTS */
 	total_tx_desc = BOND_MODE_8023AX_SLAVE_TX_PKTS;
 	for (q_id = 0; q_id < bond_dev->data->nb_tx_queues; q_id++) {
 		bd_tx_q = (struct bond_tx_queue*)bond_dev->data->tx_queues[q_id];
-		total_tx_desc += bd_tx_q->nb_tx_desc;
+		total_tx_desc += bd_tx_q->nb_tx_desc + cache_flushthresh;
 	}
 
 	snprintf(mem_name, RTE_DIM(mem_name), "slave_port%u_pool", slave_id);
 	port->mbuf_pool = rte_mempool_create(mem_name,
-		total_tx_desc, element_size,
-		RTE_MEMPOOL_CACHE_MAX_SIZE >= 32 ? 32 : RTE_MEMPOOL_CACHE_MAX_SIZE,
+		total_tx_desc, element_size, cache_size,
 		sizeof(struct rte_pktmbuf_pool_private), rte_pktmbuf_pool_init,
 		NULL, rte_pktmbuf_init, NULL, socket_id, MEMPOOL_F_NO_SPREAD);
 
-- 
1.7.1