Fix: Multiple health monitoring fixes

[lttng-tools.git] / src / bin / lttng-sessiond / health.h

/*
 * Copyright (C) 2012 - David Goulet <dgoulet@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.
 */

#ifndef _HEALTH_H
#define _HEALTH_H

#include <stdint.h>
#include <urcu/uatomic.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)

enum health_flags {
	HEALTH_EXIT = (1U << 0),
	HEALTH_ERROR = (1U << 1),
};

struct health_state {
	/*
	 * last counter is only read and updated by the health_check
	 * thread (single updater).
	 */
	unsigned long last;
	/*
	 * current and flags are updated by multiple threads concurrently.
	 */
	unsigned long current;		/* progress counter, updated atomically */
	enum health_flags flags;	/* other flags, updated atomically */
};

/* Health state counters for the client command thread */
extern struct health_state health_thread_cmd;

/* Health state counters for the application management thread */
extern struct health_state health_thread_app_manage;

/* Health state counters for the application registration thread */
extern struct health_state health_thread_app_reg;

/* Health state counters for the kernel thread */
extern struct health_state health_thread_kernel;

/*
 * Update current counter by 1 to indicate that the thread entered or
 * left a blocking state caused by a poll().
 */
static inline void health_poll_update(struct health_state *state)
{
	assert(state);
	uatomic_add(&state->current, HEALTH_POLL_VALUE);
}

/*
 * Update current counter by 2 indicates progress in execution of a
 * thread.
 */
static inline void health_code_update(struct health_state *state)
{
	assert(state);
	uatomic_add(&state->current, HEALTH_CODE_VALUE);
}

/*
 * Set health "exit" flag.
 */
static inline void health_exit(struct health_state *state)
{
	assert(state);
	uatomic_or(&state->flags, HEALTH_EXIT);
}

/*
 * Set health "error" flag.
 */
static inline void health_error(struct health_state *state)
{
	assert(state);
	uatomic_or(&state->flags, HEALTH_ERROR);
}

/*
 * Init health state.
 */
static inline void health_init(struct health_state *state)
{
	assert(state);
	uatomic_set(&state->last, 0);
	uatomic_set(&state->current, 0);
	uatomic_set(&state->flags, 0);
}

int health_check_state(struct health_state *state);

#endif /* _HEALTH_H */