Move health into its own common/ static library

[lttng-tools.git] / include / lttng / health-internal.h

diff --git a/include/lttng/health-internal.h b/include/lttng/health-internal.h
new file mode 100644 (file)
index 0000000..764e998
--- /dev/null
+++ b/include/lttng/health-internal.h
@@ -0,0 +1,116 @@
+#ifndef HEALTH_INTERNAL_H
+#define HEALTH_INTERNAL_H
+
+/*
+ * Copyright (C) 2012 - David Goulet <dgoulet@efficios.com>
+ * Copyright (C) 2013 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License, version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program; if not, write to the Free Software Foundation, Inc., 51
+ * Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#include <assert.h>
+#include <time.h>
+#include <pthread.h>
+#include <urcu/tls-compat.h>
+#include <urcu/uatomic.h>
+#include <urcu/list.h>
+
+/*
+ * These are the value added to the current state depending of the position in
+ * the thread where is either waiting on a poll() or running in the code.
+ */
+#define HEALTH_POLL_VALUE      (1UL << 0)
+#define HEALTH_CODE_VALUE      (1UL << 1)
+
+#define HEALTH_IS_IN_POLL(x)   ((x) & HEALTH_POLL_VALUE)
+
+struct health_app;
+
+enum health_flags {
+       HEALTH_ERROR                     = (1U << 0),
+};
+
+struct health_state {
+       /*
+        * last counter and last_time are only read and updated by the health_check
+        * thread (single updater).
+        */
+       unsigned long last;
+       struct timespec last_time;
+
+       /*
+        * current and flags are updated by multiple threads concurrently.
+        */
+       unsigned long current;          /* progress counter, updated atomically */
+       enum health_flags flags;        /* other flags, updated atomically */
+       int type;                       /* Indicates the nature of the thread. */
+       /* Node of the global TLS state list. */
+       struct cds_list_head node;
+};
+
+/* Declare TLS health state. */
+extern DECLARE_URCU_TLS(struct health_state, health_state);
+
+/*
+ * Update current counter by 1 to indicate that the thread entered or left a
+ * blocking state caused by a poll(). If the counter's value is not an even
+ * number (meaning a code execution flow), an assert() is raised.
+ */
+static inline void health_poll_entry(void)
+{
+       /* Code MUST be in code execution state which is an even number. */
+       assert(!(uatomic_read(&URCU_TLS(health_state).current)
+                               & HEALTH_POLL_VALUE));
+
+       uatomic_add(&URCU_TLS(health_state).current, HEALTH_POLL_VALUE);
+}
+
+/*
+ * Update current counter by 1 indicating the exit of a poll or blocking call.
+ * If the counter's value is not an odd number (a poll execution), an assert()
+ * is raised.
+ */
+static inline void health_poll_exit(void)
+{
+       /* Code MUST be in poll execution state which is an odd number. */
+       assert(uatomic_read(&URCU_TLS(health_state).current)
+                               & HEALTH_POLL_VALUE);
+
+       uatomic_add(&URCU_TLS(health_state).current, HEALTH_POLL_VALUE);
+}
+
+/*
+ * Update current counter by 2 indicates progress in execution of a
+ * thread.
+ */
+static inline void health_code_update(void)
+{
+       uatomic_add(&URCU_TLS(health_state).current, HEALTH_CODE_VALUE);
+}
+
+/*
+ * Set health "error" flag.
+ */
+static inline void health_error(void)
+{
+       uatomic_or(&URCU_TLS(health_state).flags, HEALTH_ERROR);
+}
+
+struct health_app *health_app_create(int nr_types);
+void health_app_destroy(struct health_app *ha);
+int health_check_state(struct health_app *ha, int type);
+void health_register(struct health_app *ha, int type);
+void health_unregister(struct health_app *ha);
+
+#endif /* HEALTH_INTERNAL_H */