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netdev-dpdk: Free mempool only when no in-use mbufs.

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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, create a free list of
mempools and sweep it anytime a port tries to get a
mempool.

Fixes: 8d38823bdf ("netdev-dpdk: fix memory leak")
Cc: mark.b.kavanagh81@gmail.com
Cc: Ilya Maximets <i.maximets@samsung.com>
Reported-by: Venkatesan Pradeep <venkatesan.pradeep@ericsson.com>
Signed-off-by: Kevin Traynor <ktraynor@redhat.com>
Signed-off-by: Ian Stokes <ian.stokes@intel.com>
This commit is contained in:
Kevin Traynor
2018-04-13 18:40:13 +01:00
committed by Ian Stokes
parent 293e7c56f6
commit 91fccdad72
1 changed files with 81 additions and 5 deletions
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86
lib/netdev-dpdk.c
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@@ -296,6 +296,16 @@ static struct ovs_list dpdk_list OVS_GUARDED_BY(dpdk_mutex)
static struct ovs_mutex dpdk_mp_mutex OVS_ACQ_AFTER(dpdk_mutex)
= OVS_MUTEX_INITIALIZER;
/* Contains all 'struct dpdk_mp's. */
static struct ovs_list dpdk_mp_free_list OVS_GUARDED_BY(dpdk_mp_mutex)
= OVS_LIST_INITIALIZER(&dpdk_mp_free_list);
/* Wrapper for a mempool released but not yet freed. */
struct dpdk_mp {
struct rte_mempool *mp;
struct ovs_list list_node OVS_GUARDED_BY(dpdk_mp_mutex);
};
/* There should be one 'struct dpdk_tx_queue' created for
* each cpu core. */
struct dpdk_tx_queue {
@@ -511,6 +521,58 @@ ovs_rte_pktmbuf_init(struct rte_mempool *mp OVS_UNUSED,
dp_packet_init_dpdk((struct dp_packet *) pkt, pkt->buf_len);
}
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)
{
struct dpdk_mp *dmp, *next;
ovs_mutex_lock(&dpdk_mp_mutex);
LIST_FOR_EACH_SAFE (dmp, next, list_node, &dpdk_mp_free_list) {
if (dpdk_mp_full(dmp->mp)) {
VLOG_DBG("Freeing mempool \"%s\"", dmp->mp->name);
ovs_list_remove(&dmp->list_node);
rte_mempool_free(dmp->mp);
rte_free(dmp);
}
}
ovs_mutex_unlock(&dpdk_mp_mutex);
}
/* Ensure a mempool will not be freed. */
static void
dpdk_mp_do_not_free(struct rte_mempool *mp) OVS_REQUIRES(dpdk_mp_mutex)
{
struct dpdk_mp *dmp, *next;
LIST_FOR_EACH_SAFE (dmp, next, list_node, &dpdk_mp_free_list) {
if (dmp->mp == mp) {
VLOG_DBG("Removing mempool \"%s\" from free list", dmp->mp->name);
ovs_list_remove(&dmp->list_node);
rte_free(dmp);
break;
}
}
}
/* Returns a valid pointer when either of the following is true:
* - a new mempool was just created;
* - a matching mempool already exists. */
@@ -577,6 +639,8 @@ dpdk_mp_create(struct netdev_dpdk *dev, int mtu)
* that's not the case we keep track of it. */
VLOG_DBG("A mempool with name \"%s\" already exists at %p.",
mp_name, mp);
/* Ensure this reused mempool will not be freed. */
dpdk_mp_do_not_free(mp);
} else {
VLOG_ERR("Failed mempool \"%s\" create request of %u mbufs",
mp_name, n_mbufs);
@@ -589,15 +653,25 @@ dpdk_mp_create(struct netdev_dpdk *dev, int mtu)
/* Release an existing mempool. */
static void
dpdk_mp_free(struct rte_mempool *mp)
dpdk_mp_release(struct rte_mempool *mp)
{
if (!mp) {
return;
}
ovs_mutex_lock(&dpdk_mp_mutex);
VLOG_DBG("Releasing \"%s\" mempool", mp->name);
rte_mempool_free(mp);
if (dpdk_mp_full(mp)) {
VLOG_DBG("Freeing mempool \"%s\"", mp->name);
rte_mempool_free(mp);
} else {
struct dpdk_mp *dmp;
dmp = dpdk_rte_mzalloc(sizeof *dmp);
if (dmp) {
dmp->mp = mp;
ovs_list_push_back(&dpdk_mp_free_list, &dmp->list_node);
}
}
ovs_mutex_unlock(&dpdk_mp_mutex);
}
@@ -615,6 +689,8 @@ netdev_dpdk_mempool_configure(struct netdev_dpdk *dev)
struct rte_mempool *mp;
int ret = 0;
dpdk_mp_sweep();
mp = dpdk_mp_create(dev, FRAME_LEN_TO_MTU(buf_size));
if (!mp) {
VLOG_ERR("Failed to create memory pool for netdev "
@@ -627,7 +703,7 @@ netdev_dpdk_mempool_configure(struct netdev_dpdk *dev)
* that is currently used, then the existing mempool is returned. */
if (dev->mp != mp) {
/* A new mempool was created, release the previous one. */
dpdk_mp_free(dev->mp);
dpdk_mp_release(dev->mp);
} else {
ret = EEXIST;
}
@@ -1082,7 +1158,7 @@ common_destruct(struct netdev_dpdk *dev)
OVS_EXCLUDED(dev->mutex)
{
rte_free(dev->tx_q);
dpdk_mp_free(dev->mp);
dpdk_mp_release(dev->mp);
ovs_list_remove(&dev->list_node);
free(ovsrcu_get_protected(struct ingress_policer *,