MINOR: session/trace: enable very minimal session tracing

By having traces at the session level, it becomes possible to start
traces on session creation and pause them on session end. Doing so
will soon open new possibilties to synchronize multiple traces.

diff --git a/src/session.c b/src/session.c
index 710118024313abba9dff1a28c48f0a338f518b2c..60cb8bf411edc5dddab3b4b893a722cb9b83af45 100644 (file)
--- a/src/session.c
+++ b/src/session.c
@@ -23,6 +23,7 @@
 #include <haproxy/session.h>
 #include <haproxy/tcp_rules.h>
 #include <haproxy/tools.h>
+#include <haproxy/trace.h>
 #include <haproxy/vars.h>
 
 
@@ -32,6 +33,35 @@ DECLARE_POOL(pool_head_sess_priv_conns, "session priv conns list",
 
 int conn_complete_session(struct connection *conn);
 
+static const struct trace_event sess_trace_events[] = {
+#define           SESS_EV_NEW       (1ULL <<  0)
+       { .mask = SESS_EV_NEW,      .name = "sess_new",     .desc = "new session creation" },
+#define           SESS_EV_END       (1ULL <<  1)
+       { .mask = SESS_EV_END,      .name = "sess_end",     .desc = "session termination" },
+#define           SESS_EV_ERR       (1ULL <<  1)
+       { .mask = SESS_EV_ERR,      .name = "sess_err",     .desc = "session error" },
+       { }
+};
+
+static const struct name_desc sess_trace_lockon_args[4] = {
+       /* arg1 */ { /* already used by the session */ },
+       /* arg2 */ { },
+       /* arg3 */ { },
+       /* arg4 */ { }
+};
+
+static struct trace_source trace_sess __read_mostly = {
+       .name = IST("session"),
+       .desc = "client session management",
+       .arg_def = TRC_ARG1_SESS,  // TRACE()'s first argument is always a session
+       .known_events = sess_trace_events,
+       .lockon_args = sess_trace_lockon_args,
+       .report_events = ~0,  // report everything by default
+};
+
+#define TRACE_SOURCE &trace_sess
+INITCALL1(STG_REGISTER, trace_register_source, TRACE_SOURCE);
+
 /* Create a a new session and assign it to frontend <fe>, listener <li>,
  * origin <origin>, set the current date and clear the stick counters pointers.
  * Returns the session upon success or NULL. The session may be released using
@@ -41,6 +71,8 @@ struct session *session_new(struct proxy *fe, struct listener *li, enum obj_type
 {
        struct session *sess;
 
+       TRACE_ENTER(SESS_EV_NEW);
+
        sess = pool_alloc(pool_head_session);
        if (sess) {
                sess->listener = li;
@@ -66,10 +98,13 @@ struct session *session_new(struct proxy *fe, struct listener *li, enum obj_type
                sess->flags = SESS_FL_NONE;
                sess->src = NULL;
                sess->dst = NULL;
+               TRACE_STATE("new session", SESS_EV_NEW, sess);
        }
+       TRACE_LEAVE(SESS_EV_NEW);
        return sess;
  out_fail_alloc:
        pool_free(pool_head_session, sess);
+       TRACE_DEVEL("leaving in error", SESS_EV_NEW|SESS_EV_END|SESS_EV_ERR);
        return NULL;
 }
 
@@ -78,6 +113,9 @@ void session_free(struct session *sess)
        struct connection *conn, *conn_back;
        struct sess_priv_conns *pconns, *pconns_back;
 
+       TRACE_ENTER(SESS_EV_END);
+       TRACE_STATE("releasing session", SESS_EV_END, sess);
+
        if (sess->flags & SESS_FL_RELEASE_LI) {
                /* listener must be set for session used to account FE conns. */
                BUG_ON(!sess->listener);
@@ -104,6 +142,8 @@ void session_free(struct session *sess)
        sockaddr_free(&sess->dst);
        pool_free(pool_head_session, sess);
        _HA_ATOMIC_DEC(&jobs);
+
+       TRACE_LEAVE(SESS_EV_END);
 }
 
 /* callback used from the connection/mux layer to notify that a connection is