On 28 Jun 2018, at 17:41, Tiago Lam wrote:
A new mutex, 'nonpmd_mp_mutex', has been introduced to serialise
allocation and free operations by non-pmd threads on a given mempool.
free_dpdk_buf() has been modified to make use of the introduced mutex.
Signed-off-by: Tiago Lam <[email protected]>
---
lib/netdev-dpdk.c | 30 +++++++++++++++++++++++++++---
1 file changed, 27 insertions(+), 3 deletions(-)
diff --git a/lib/netdev-dpdk.c b/lib/netdev-dpdk.c
index c5c6aab..5c62d85 100644
--- a/lib/netdev-dpdk.c
+++ b/lib/netdev-dpdk.c
@@ -294,6 +294,16 @@ static struct ovs_mutex dpdk_mp_mutex
OVS_ACQ_AFTER(dpdk_mutex)
static struct ovs_list dpdk_mp_free_list
OVS_GUARDED_BY(dpdk_mp_mutex)
= OVS_LIST_INITIALIZER(&dpdk_mp_free_list);
+/* This mutex must be used by non pmd threads when allocating or
freeing
+ * mbufs through mempools, when outside of the `non_pmd_mutex` mutex,
in struct
+ * dp_netdev.
+ * The reason, as pointed out in the "Known Issues" section in DPDK's
EAL docs,
+ * is that the implementation on which mempool is based off is
non-preemptable.
+ * Since non-pmds may end up not being pinned this could lead to the
preemption
+ * between non-pmds performing operations on the same mempool, which
could lead
+ * to memory corruption. */
+static struct ovs_mutex nonpmd_mp_mutex = OVS_MUTEX_INITIALIZER;
+
/* Wrapper for a mempool released but not yet freed. */
struct dpdk_mp {
struct rte_mempool *mp;
@@ -462,6 +472,8 @@ struct netdev_rxq_dpdk {
dpdk_port_t port_id;
};
+static bool dpdk_thread_is_pmd(void);
+
static void netdev_dpdk_destruct(struct netdev *netdev);
static void netdev_dpdk_vhost_destruct(struct netdev *netdev);
@@ -495,6 +507,12 @@ dpdk_buf_size(int mtu)
NETDEV_DPDK_MBUF_ALIGN);
}
+static bool
+dpdk_thread_is_pmd(void)
+{
+ return rte_lcore_id() != NON_PMD_CORE_ID;
+}
+
/* Allocates an area of 'sz' bytes from DPDK. The memory is zero'ed.
*
* Unlike xmalloc(), this function can return NULL on failure. */
@@ -505,11 +523,17 @@ dpdk_rte_mzalloc(size_t sz)
}
void
-free_dpdk_buf(struct dp_packet *p)
+free_dpdk_buf(struct dp_packet *packet)
{
- struct rte_mbuf *pkt = (struct rte_mbuf *) p;
+ if (!dpdk_thread_is_pmd()) {
+ ovs_mutex_lock(&nonpmd_mp_mutex);
+ }
- rte_pktmbuf_free(pkt);
+ rte_pktmbuf_free((struct rte_mbuf *) packet);
Rather than casting it, it should be &packet->mbuf, some one might
change the order in the dp_packet structure.
+
+ if (!dpdk_thread_is_pmd()) {
+ ovs_mutex_unlock(&nonpmd_mp_mutex);
+ }
}
static void
--
2.7.4
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