On 11 Jun 2018, at 18:21, 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.
Can you explain why we need the mutex here? Can't see any reason why
rte_pktmbuf_free() needs to be protected for non-pmd threads?
free_dpdk_buf() has been modified to make use of the introduced mutex.
Signed-off-by: Tiago Lam <[email protected]>
---
lib/netdev-dpdk.c | 21 ++++++++++++++++++++-
1 file changed, 20 insertions(+), 1 deletion(-)
diff --git a/lib/netdev-dpdk.c b/lib/netdev-dpdk.c
index f546507..efd7c20 100644
--- a/lib/netdev-dpdk.c
+++ b/lib/netdev-dpdk.c
@@ -294,6 +294,10 @@ 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. */
+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;
@@ -461,6 +465,8 @@ 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);
@@ -494,6 +500,12 @@ dpdk_buf_size(int mtu)
NETDEV_DPDK_MBUF_ALIGN);
}
+static bool
+dpdk_thread_is_pmd(void)
+{
+ return rte_lcore_id() != NON_PMD_CORE_ID;
Will this continue to work with newer DPDK versions? I've not looked at
it in detail, but I did notice that the vhost threads in the newer DPDK
now get created with rte_ctrl_thread_create() and does some lcore
mangling.
+}
+
/* Allocates an area of 'sz' bytes from DPDK. The memory is zero'ed.
*
* Unlike xmalloc(), this function can return NULL on failure. */
@@ -506,9 +518,16 @@ dpdk_rte_mzalloc(size_t sz)
void
free_dpdk_buf(struct dp_packet *p)
{
- struct rte_mbuf *pkt = (struct rte_mbuf *) p;
+ if (!dpdk_thread_is_pmd()) {
+ ovs_mutex_lock(&nonpmd_mp_mutex);
+ }
+ struct rte_mbuf *pkt = (struct rte_mbuf *) p;
Should we not use a container_of macro here?
rte_pktmbuf_free(pkt);
+
+ if (!dpdk_thread_is_pmd()) {
+ ovs_mutex_unlock(&nonpmd_mp_mutex);
+ }
}
static void
--
2.7.4
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