[PATCH v4 3/3] ethdev: cleanup shared data with the last port

[David Marchand]

If no port is allocated and no port owner is still registered,
ethdev from a primary process may release the memzone used to store
port data.
This makes it possible for the DPDK memory allocator to release
associated resources back to the OS.

Signed-off-by: David Marchand <david.march...@redhat.com>
Acked-by: Morten Brørup <m...@smartsharesystems.com>
---
Changes since v2:
- tracked owners count and and avoided releasing shared mem if some
  owner is still registered,

---
 lib/ethdev/ethdev_driver.c  |  6 ++++++
 lib/ethdev/ethdev_private.c | 21 ++++++++++++++++++++-
 lib/ethdev/ethdev_private.h |  4 ++++
 lib/ethdev/rte_ethdev.c     |  3 +++
 4 files changed, 33 insertions(+), 1 deletion(-)

diff --git a/lib/ethdev/ethdev_driver.c b/lib/ethdev/ethdev_driver.c
index b339e325a0..fff4b7b4cd 100644
--- a/lib/ethdev/ethdev_driver.c
+++ b/lib/ethdev/ethdev_driver.c
@@ -115,6 +115,8 @@ rte_eth_dev_allocate(const char *name)
        eth_dev->data->backer_port_id = RTE_MAX_ETHPORTS;
        eth_dev->data->mtu = RTE_ETHER_MTU;
        pthread_mutex_init(&eth_dev->data->flow_ops_mutex, NULL);
+       RTE_ASSERT(rte_eal_process_type() == RTE_PROC_PRIMARY);
+       eth_dev_shared_data->allocated_ports++;
 
 unlock:
        rte_spinlock_unlock(rte_mcfg_ethdev_get_lock());
@@ -265,6 +267,10 @@ rte_eth_dev_release_port(struct rte_eth_dev *eth_dev)
                rte_free(eth_dev->data->dev_private);
                pthread_mutex_destroy(&eth_dev->data->flow_ops_mutex);
                memset(eth_dev->data, 0, sizeof(struct rte_eth_dev_data));
+               eth_dev->data = NULL;
+
+               eth_dev_shared_data->allocated_ports--;
+               eth_dev_shared_data_release();
        }
 
        rte_spinlock_unlock(rte_mcfg_ethdev_get_lock());
diff --git a/lib/ethdev/ethdev_private.c b/lib/ethdev/ethdev_private.c
index 911de1e595..aea9112cc2 100644
--- a/lib/ethdev/ethdev_private.c
+++ b/lib/ethdev/ethdev_private.c
@@ -11,6 +11,7 @@
 
 static const char *MZ_RTE_ETH_DEV_DATA = "rte_eth_dev_data";
 
+static const struct rte_memzone *eth_dev_shared_mz;
 struct eth_dev_shared *eth_dev_shared_data;
 
 /* spinlock for eth device callbacks */
@@ -324,7 +325,7 @@ eth_dev_shared_data_prepare(void)
        const unsigned int flags = 0;
        const struct rte_memzone *mz;
 
-       if (eth_dev_shared_data == NULL) {
+       if (eth_dev_shared_mz == NULL) {
                if (rte_eal_process_type() == RTE_PROC_PRIMARY) {
                        /* Allocate port data and ownership shared memory. */
                        mz = rte_memzone_reserve(MZ_RTE_ETH_DEV_DATA,
@@ -337,10 +338,13 @@ eth_dev_shared_data_prepare(void)
                        goto out;
                }
 
+               eth_dev_shared_mz = mz;
                eth_dev_shared_data = mz->addr;
                if (rte_eal_process_type() == RTE_PROC_PRIMARY) {
+                       eth_dev_shared_data->allocated_owners = 0;
                        eth_dev_shared_data->next_owner_id =
                                        RTE_ETH_DEV_NO_OWNER + 1;
+                       eth_dev_shared_data->allocated_ports = 0;
                        memset(eth_dev_shared_data->data, 0,
                               sizeof(eth_dev_shared_data->data));
                }
@@ -349,6 +353,21 @@ eth_dev_shared_data_prepare(void)
        return eth_dev_shared_data;
 }
 
+void
+eth_dev_shared_data_release(void)
+{
+       RTE_ASSERT(rte_eal_process_type() == RTE_PROC_PRIMARY);
+
+       if (eth_dev_shared_data->allocated_ports != 0)
+               return;
+       if (eth_dev_shared_data->allocated_owners != 0)
+               return;
+
+       rte_memzone_free(eth_dev_shared_mz);
+       eth_dev_shared_mz = NULL;
+       eth_dev_shared_data = NULL;
+}
+
 void
 eth_dev_rxq_release(struct rte_eth_dev *dev, uint16_t qid)
 {
diff --git a/lib/ethdev/ethdev_private.h b/lib/ethdev/ethdev_private.h
index 1572da7b48..0d36b9c30f 100644
--- a/lib/ethdev/ethdev_private.h
+++ b/lib/ethdev/ethdev_private.h
@@ -14,7 +14,9 @@
 #include "rte_ethdev.h"
 
 struct eth_dev_shared {
+       uint64_t allocated_owners;
        uint64_t next_owner_id;
+       uint64_t allocated_ports;
        struct rte_eth_dev_data data[RTE_MAX_ETHPORTS];
 };
 
@@ -69,6 +71,8 @@ void eth_dev_fp_ops_setup(struct rte_eth_fp_ops *fpo,
 
 void *eth_dev_shared_data_prepare(void)
        __rte_exclusive_locks_required(rte_mcfg_ethdev_get_lock());
+void eth_dev_shared_data_release(void)
+       __rte_exclusive_locks_required(rte_mcfg_ethdev_get_lock());
 
 void eth_dev_rxq_release(struct rte_eth_dev *dev, uint16_t qid);
 void eth_dev_txq_release(struct rte_eth_dev *dev, uint16_t qid);
diff --git a/lib/ethdev/rte_ethdev.c b/lib/ethdev/rte_ethdev.c
index 5c9495ecfe..61572d0cd1 100644
--- a/lib/ethdev/rte_ethdev.c
+++ b/lib/ethdev/rte_ethdev.c
@@ -444,6 +444,7 @@ rte_eth_dev_owner_new(uint64_t *owner_id)
 
        if (eth_dev_shared_data_prepare() != NULL) {
                *owner_id = eth_dev_shared_data->next_owner_id++;
+               eth_dev_shared_data->allocated_owners++;
                ret = 0;
        } else {
                ret = -ENOMEM;
@@ -566,6 +567,8 @@ rte_eth_dev_owner_delete(const uint64_t owner_id)
                RTE_ETHDEV_LOG(NOTICE,
                        "All port owners owned by %016"PRIx64" identifier have 
removed\n",
                        owner_id);
+               eth_dev_shared_data->allocated_owners--;
+               eth_dev_shared_data_release();
        } else {
                RTE_ETHDEV_LOG(ERR,
                               "Invalid owner ID=%016"PRIx64"\n",
-- 
2.41.0