vcl: support for eventfd mq signaling

- support eventfd based mq signaling. Based on configuration, vcl
epoll/select can use either condvars or epoll on mq eventfds.
- add vcl support for memfd segments
- vpp explicitly registers cut-through segments with apps/vcl
- if using eventfd, make ldp allow one call to libc_epoll_create. Needed
for the message queue epfd
- update svm_queue_t to allow blocking calls with eventfd signaling.

Change-Id: I064151ac370bbe29bb16c968bf4e3659c8286bea
Signed-off-by: Florin Coras <fcoras@cisco.com>

1 files changed, 151 insertions, 0 deletions

diff --git a/src/vcl/vcl_private.c b/src/vcl/vcl_private.c
new file mode 100644
index 00000000000..48abbafe646
--- /dev/null
+++ b/src/vcl/vcl_private.c
@@ -0,0 +1,151 @@
+/*
+ * Copyright (c) 2018 Cisco and/or its affiliates.
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this
+ * You may obtain a copy of the License at:
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <vcl/vcl_private.h>
+
+vcl_cut_through_registration_t *
+vcl_ct_registration_lock_and_alloc (void)
+{
+  vcl_cut_through_registration_t *cr;
+  pool_get (vcm->cut_through_registrations, cr);
+  clib_spinlock_lock (&vcm->ct_registration_lock);
+  memset (cr, 0, sizeof (*cr));
+  cr->epoll_evt_conn_index = -1;
+  return cr;
+}
+
+u32
+vcl_ct_registration_index (vcl_cut_through_registration_t * ctr)
+{
+  return (ctr - vcm->cut_through_registrations);
+}
+
+void
+vcl_ct_registration_unlock (void)
+{
+  clib_spinlock_unlock (&vcm->ct_registration_lock);
+}
+
+vcl_cut_through_registration_t *
+vcl_ct_registration_get (u32 ctr_index)
+{
+  if (pool_is_free_index (vcm->cut_through_registrations, ctr_index))
+    return 0;
+  return pool_elt_at_index (vcm->cut_through_registrations, ctr_index);
+}
+
+vcl_cut_through_registration_t *
+vcl_ct_registration_lock_and_lookup (uword mq_addr)
+{
+  uword *p;
+  clib_spinlock_lock (&vcm->ct_registration_lock);
+  p = hash_get (vcm->ct_registration_by_mq, mq_addr);
+  if (!p)
+    return 0;
+  return vcl_ct_registration_get (p[0]);
+}
+
+void
+vcl_ct_registration_lookup_add (uword mq_addr, u32 ctr_index)
+{
+  hash_set (vcm->ct_registration_by_mq, mq_addr, ctr_index);
+}
+
+void
+vcl_ct_registration_lookup_del (uword mq_addr)
+{
+  hash_unset (vcm->ct_registration_by_mq, mq_addr);
+}
+
+void
+vcl_ct_registration_del (vcl_cut_through_registration_t * ctr)
+{
+  pool_put (vcm->cut_through_registrations, ctr);
+}
+
+vcl_mq_evt_conn_t *
+vcl_mq_evt_conn_alloc (void)
+{
+  vcl_mq_evt_conn_t *mqc;
+  pool_get (vcm->mq_evt_conns, mqc);
+  memset (mqc, 0, sizeof (*mqc));
+  return mqc;
+}
+
+u32
+vcl_mq_evt_conn_index (vcl_mq_evt_conn_t * mqc)
+{
+  return (mqc - vcm->mq_evt_conns);
+}
+
+vcl_mq_evt_conn_t *
+vcl_mq_evt_conn_get (u32 mq_conn_idx)
+{
+  return pool_elt_at_index (vcm->mq_evt_conns, mq_conn_idx);
+}
+
+int
+vcl_mq_epoll_add_evfd (svm_msg_q_t * mq)
+{
+  struct epoll_event e = { 0 };
+  vcl_mq_evt_conn_t *mqc;
+  u32 mqc_index;
+  int mq_fd;
+
+  mq_fd = svm_msg_q_get_consumer_eventfd (mq);
+
+  if (vcm->mqs_epfd < 0 || mq_fd == -1)
+    return -1;
+
+  mqc = vcl_mq_evt_conn_alloc ();
+  mqc_index = vcl_mq_evt_conn_index (mqc);
+  mqc->mq_fd = mq_fd;
+  mqc->mq = mq;
+
+  e.events = EPOLLIN;
+  e.data.u32 = mqc_index;
+  if (epoll_ctl (vcm->mqs_epfd, EPOLL_CTL_ADD, mq_fd, &e) < 0)
+    {
+      clib_warning ("failed to add mq eventfd to mq epoll fd");
+      return -1;
+    }
+
+  return mqc_index;
+}
+
+int
+vcl_mq_epoll_del_evfd (u32 mqc_index)
+{
+  vcl_mq_evt_conn_t *mqc;
+
+  if (vcm->mqs_epfd || mqc_index == ~0)
+    return -1;
+
+  mqc = vcl_mq_evt_conn_get (mqc_index);
+  if (epoll_ctl (vcm->mqs_epfd, EPOLL_CTL_DEL, mqc->mq_fd, 0) < 0)
+    {
+      clib_warning ("failed to del mq eventfd to mq epoll fd");
+      return -1;
+    }
+  return 0;
+}
+
+/*
+ * fd.io coding-style-patch-verification: ON
+ *
+ * Local Variables:
+ * eval: (c-set-style "gnu")
+ * End:
+ */