Fix MP hazard in interrupt node scheduling

[vpp.git] / src / vlib / main.c

diff --git a/src/vlib/main.c b/src/vlib/main.c
index fd9937f..f915aa4 100644 (file)
--- a/src/vlib/main.c
+++ b/src/vlib/main.c
@@ -1423,6 +1423,13 @@ dispatch_suspended_process (vlib_main_t * vm,
   return t;
 }
 
+void vl_api_send_pending_rpc_requests (vlib_main_t *) __attribute__ ((weak));
+void
+vl_api_send_pending_rpc_requests (vlib_main_t * vm)
+{
+}
+
+
 static_always_inline void
 vlib_main_or_worker_loop (vlib_main_t * vm, int is_main)
 {
@@ -1475,6 +1482,9 @@ vlib_main_or_worker_loop (vlib_main_t * vm, int is_main)
     {
       vlib_node_runtime_t *n;
 
+      if (PREDICT_FALSE (_vec_len (vm->pending_rpc_requests) > 0))
+       vl_api_send_pending_rpc_requests (vm);
+
       if (!is_main)
        {
          vlib_worker_thread_barrier_check ();
@@ -1504,13 +1514,19 @@ vlib_main_or_worker_loop (vlib_main_t * vm, int is_main)
 
       /* Next handle interrupts. */
       {
+       /* unlocked read, for performance */
        uword l = _vec_len (nm->pending_interrupt_node_runtime_indices);
        uword i;
-       if (l > 0)
+       if (PREDICT_FALSE (l > 0))
          {
            u32 *tmp;
            if (!is_main)
-             clib_spinlock_lock (&nm->pending_interrupt_lock);
+             {
+               clib_spinlock_lock (&nm->pending_interrupt_lock);
+               /* Re-read w/ lock held, in case another thread added an item */
+               l = _vec_len (nm->pending_interrupt_node_runtime_indices);
+             }
+
            tmp = nm->pending_interrupt_node_runtime_indices;
            nm->pending_interrupt_node_runtime_indices =
              last_node_runtime_indices;
@@ -1742,6 +1758,9 @@ vlib_main (vlib_main_t * volatile vm, unformat_input_t * input)
                            10e-6 /* timer period 10us */ ,
                            ~0 /* max expirations per call */ );
 
+  vec_validate (vm->pending_rpc_requests, 0);
+  _vec_len (vm->pending_rpc_requests) = 0;
+
   switch (clib_setjmp (&vm->main_loop_exit, VLIB_MAIN_LOOP_EXIT_NONE))
     {
     case VLIB_MAIN_LOOP_EXIT_NONE: