Add function calls for request lifecycle tracing

Makefile.am

@@ -1,6 +1,9 @@
 ACLOCAL_AMFLAGS = -I m4
 AM_CFLAGS += $(CODE_COVERAGE_CFLAGS)
 
+# Not clobbering the base pointer helps bpftrace construct backtraces
+AM_CFLAGS += -fno-omit-frame-pointer
+
 include_HEADERS = include/raft.h
 
 raftincludedir = $(includedir)/raft
@@ -19,6 +22,7 @@ libraft_la_SOURCES = \
   src/entry.c \
   src/err.c \
   src/heap.c \
+  src/lifecycle.c \
   src/log.c \
   src/membership.c \
   src/progress.c \

src/client.c

@@ -2,6 +2,7 @@
 #include "assert.h"
 #include "configuration.h"
 #include "err.h"
+#include "lifecycle.h"
 #include "log.h"
 #include "membership.h"
 #include "progress.h"
@@ -47,7 +48,7 @@ int raft_apply(struct raft *r,
         goto err;
     }
 
-    QUEUE_PUSH(&r->leader_state.requests, &req->queue);
+    lifecycleRequestStart(r, (struct request *)req);
 
     rv = replicationTrigger(r, index);
     if (rv != 0) {
@@ -96,7 +97,7 @@ int raft_barrier(struct raft *r, struct raft_barrier *req, raft_barrier_cb cb)
         goto err_after_buf_alloc;
     }
 
-    QUEUE_PUSH(&r->leader_state.requests, &req->queue);
+    lifecycleRequestStart(r, (struct request *)req);
 
     rv = replicationTrigger(r, index);
     if (rv != 0) {

src/lifecycle.c

@@ -0,0 +1,15 @@
+#include "lifecycle.h"
+#include "queue.h"
+
+#include <stdlib.h>
+
+void lifecycleRequestStart(struct raft *r, struct request *req)
+{
+    QUEUE_PUSH(&r->leader_state.requests, &req->queue);
+}
+
+void lifecycleRequestEnd(struct raft *r, struct request *req)
+{
+    (void)r;
+    QUEUE_REMOVE(&req->queue);
+}

src/lifecycle.h

@@ -0,0 +1,10 @@
+#ifndef LIFECYCLE_H_
+#define LIFECYCLE_H_
+
+#include "../include/raft.h"
+#include "request.h"
+
+void lifecycleRequestStart(struct raft *r, struct request *req);
+void lifecycleRequestEnd(struct raft *r, struct request *req);
+
+#endif

src/replication.c

@@ -9,6 +9,7 @@
 #endif
 #include "err.h"
 #include "heap.h"
+#include "lifecycle.h"
 #include "log.h"
 #include "membership.h"
 #include "progress.h"
@@ -454,7 +455,7 @@ static struct request *getRequest(struct raft *r,
         req = QUEUE_DATA(head, struct request, queue);
         if (req->index == index) {
             assert(req->type == type);
-            QUEUE_REMOVE(head);
+            lifecycleRequestEnd(r, req);
             return req;
         }
     }