[ovs-dev] [branch-2.7/2.8 PATCH v3] netdev-dpdk: Free mempool only when no in-use mbufs.
Kevin Traynor
ktraynor at redhat.com
Fri Apr 20 12:24:30 UTC 2018
DPDK mempools are freed when they are no longer needed.
This can happen when a port is removed or a port's mtu
is reconfigured so that a new mempool is used.
It is possible that an mbuf is attempted to be returned
to a freed mempool from NIC Tx queues and this can lead
to a segfault.
In order to prevent this, only free mempools when they
are not needed and have no in-use mbufs. As this might
not be possible immediately, sweep the mempools anytime
a port tries to get a mempool.
Fixes: 8d38823bdf8b ("netdev-dpdk: fix memory leak")
Cc: mark.b.kavanagh81 at gmail.com
Cc: Ilya Maximets <i.maximets at samsung.com>
Reported-by: Venkatesan Pradeep <venkatesan.pradeep at ericsson.com>
Signed-off-by: Kevin Traynor <ktraynor at redhat.com>
---
lib/netdev-dpdk.c | 56 ++++++++++++++++++++++++++++++++++++++++++++-----------
1 file changed, 45 insertions(+), 11 deletions(-)
diff --git a/lib/netdev-dpdk.c b/lib/netdev-dpdk.c
index 48ffaa2..4bde232 100644
--- a/lib/netdev-dpdk.c
+++ b/lib/netdev-dpdk.c
@@ -548,8 +548,42 @@ dpdk_mp_create(int socket_id, int mtu)
}
+static int
+dpdk_mp_full(const struct rte_mempool *mp) OVS_REQUIRES(dpdk_mp_mutex)
+{
+ unsigned ring_count;
+ /* This logic is needed because rte_mempool_full() is not guaranteed to
+ * be atomic and mbufs could be moved from mempool cache --> mempool ring
+ * during the call. However, as no mbufs will be taken from the mempool
+ * at this time, we can work around it by also checking the ring entries
+ * separately and ensuring that they have not changed.
+ */
+ ring_count = rte_mempool_ops_get_count(mp);
+ if (rte_mempool_full(mp) && rte_mempool_ops_get_count(mp) == ring_count) {
+ return 1;
+ }
+
+ return 0;
+}
+
+/* Free unused mempools. */
+static void
+dpdk_mp_sweep(void) OVS_REQUIRES(dpdk_mp_mutex)
+{
+ struct dpdk_mp *dmp, *next;
+
+ LIST_FOR_EACH_SAFE (dmp, next, list_node, &dpdk_mp_list) {
+ if (!dmp->refcount && dpdk_mp_full(dmp->mp)) {
+ ovs_list_remove(&dmp->list_node);
+ rte_mempool_free(dmp->mp);
+ rte_free(dmp);
+ }
+ }
+}
+
static struct dpdk_mp *
dpdk_mp_get(int socket_id, int mtu)
{
struct dpdk_mp *dmp;
+ bool reuse = false;
ovs_mutex_lock(&dpdk_mp_mutex);
@@ -557,14 +591,18 @@ dpdk_mp_get(int socket_id, int mtu)
if (dmp->socket_id == socket_id && dmp->mtu == mtu) {
dmp->refcount++;
- goto out;
+ reuse = true;
+ break;
}
}
+ /* Sweep mempools after reuse or before create. */
+ dpdk_mp_sweep();
- dmp = dpdk_mp_create(socket_id, mtu);
- if (dmp) {
- ovs_list_push_back(&dpdk_mp_list, &dmp->list_node);
+ if (!reuse) {
+ dmp = dpdk_mp_create(socket_id, mtu);
+ if (dmp) {
+ ovs_list_push_back(&dpdk_mp_list, &dmp->list_node);
+ }
}
-out:
ovs_mutex_unlock(&dpdk_mp_mutex);
@@ -572,4 +610,5 @@ out:
}
+/* Decrement reference to a mempool. */
static void
dpdk_mp_put(struct dpdk_mp *dmp)
@@ -581,10 +620,5 @@ dpdk_mp_put(struct dpdk_mp *dmp)
ovs_mutex_lock(&dpdk_mp_mutex);
ovs_assert(dmp->refcount);
-
- if (!--dmp->refcount) {
- ovs_list_remove(&dmp->list_node);
- rte_mempool_free(dmp->mp);
- rte_free(dmp);
- }
+ dmp->refcount--;
ovs_mutex_unlock(&dpdk_mp_mutex);
}
--
1.8.3.1
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