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

/*
 * 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.
 */

#define _GNU_SOURCE
#include <assert.h>
#include <inttypes.h>
#include <stdio.h>
#include <stdlib.h>
#include <time.h>

#include <common/defaults.h>
#include <common/error.h>
#include <common/macros.h>
#include <common/sessiond-comm/inet.h>

#include "health.h"

/*
 * An application-specific error state for unregistered thread keeps
 * track of thread errors. A thread reporting a health error, normally
 * unregisters and quits. This makes the TLS health state not available
 * to the health_check_state() call so on unregister we update this
 * global error array so we can keep track of which thread was on error
 * if the TLS health state has been removed.
 */
struct health_app {
	/* List of health state, for each application thread */
	struct cds_list_head list;
	/*
	 * This lock ensures that TLS memory used for the node and its
	 * container structure don't get reclaimed after the TLS owner
	 * thread exits until we have finished using it.
	 */
	pthread_mutex_t lock;
	int nr_types;
	struct timespec time_delta;
	/* Health flags containing thread type error state */
	enum health_flags *flags;
};

/* Define TLS health state. */
DEFINE_URCU_TLS(struct health_state, health_state);

struct health_app *health_app_create(int nr_types)
{
	struct health_app *ha;

	ha = zmalloc(sizeof(*ha));
	if (!ha) {
		return NULL;
	}
	ha->flags = zmalloc(sizeof(*ha->flags));
	if (!ha->flags) {
		goto error_flags;
	}
	CDS_INIT_LIST_HEAD(&ha->list);
	pthread_mutex_init(&ha->lock, NULL);
	ha->nr_types = nr_types;
	ha->time_delta.tv_sec = DEFAULT_HEALTH_CHECK_DELTA_S;
	ha->time_delta.tv_nsec = DEFAULT_HEALTH_CHECK_DELTA_NS;
	return ha;

error_flags:
	free(ha);
	return NULL;
}

void health_app_destroy(struct health_app *ha)
{
	free(ha->flags);
	free(ha);
}

/*
 * Lock health state global list mutex.
 */
static void state_lock(struct health_app *ha)
{
	pthread_mutex_lock(&ha->lock);
}

/*
 * Unlock health state global list mutex.
 */
static void state_unlock(struct health_app *ha)
{
	pthread_mutex_unlock(&ha->lock);
}

/*
 * Set time difference in res from time_a and time_b.
 */
static void time_diff(const struct timespec *time_a,
		const struct timespec *time_b, struct timespec *res)
{
	if (time_a->tv_nsec - time_b->tv_nsec < 0) {
		res->tv_sec = time_a->tv_sec - time_b->tv_sec - 1;
		res->tv_nsec = 1000000000L + time_a->tv_sec - time_b->tv_sec;
	} else {
		res->tv_sec = time_a->tv_sec - time_b->tv_sec;
		res->tv_nsec = time_a->tv_nsec - time_b->tv_nsec;
	}
}

/*
 * Return true if time_a - time_b > diff, else false.
 */
static int time_diff_gt(const struct timespec *time_a,
		const struct timespec *time_b, const struct timespec *diff)
{
	struct timespec res;

	time_diff(time_a, time_b, &res);
	time_diff(&res, diff, &res);

	if (res.tv_sec > 0) {
		return 1;
	} else if (res.tv_sec == 0 && res.tv_nsec > 0) {
		return 1;
	}

	return 0;
}

/*
 * Validate health state. Checks for the error flag or health conditions.
 *
 * Return 0 if health is bad or else 1.
 */
static int validate_state(struct health_app *ha, struct health_state *state)
{
	int retval = 1, ret;
	unsigned long current, last;
	struct timespec current_time;

	assert(state);

	last = state->last;
	current = uatomic_read(&state->current);

	ret = clock_gettime(CLOCK_MONOTONIC, &current_time);
	if (ret < 0) {
		PERROR("Error reading time\n");
		/* error */
		retval = 0;
		goto end;
	}

	/*
	 * Thread is in bad health if flag HEALTH_ERROR is set. It is also in bad
	 * health if, after the delta delay has passed, its the progress counter
	 * has not moved and it has NOT been waiting for a poll() call.
	 */
	if (uatomic_read(&state->flags) & HEALTH_ERROR) {
		retval = 0;
		goto end;
	}

	/*
	 * Initial condition need to update the last counter and sample time, but
	 * should not check health in this initial case, because we don't know how
	 * much time has passed.
	 */
	if (state->last_time.tv_sec == 0 && state->last_time.tv_nsec == 0) {
		/* update last counter and last sample time */
		state->last = current;
		memcpy(&state->last_time, &current_time, sizeof(current_time));
	} else {
		if (time_diff_gt(&current_time, &state->last_time,
				&ha->time_delta)) {
			if (current == last && !HEALTH_IS_IN_POLL(current)) {
				/* error */
				retval = 0;
			}
			/* update last counter and last sample time */
			state->last = current;
			memcpy(&state->last_time, &current_time, sizeof(current_time));

			/* On error, stop right now and notify caller. */
			if (retval == 0) {
				goto end;
			}
		}
	}

end:
	DBG("Health state current %lu, last %lu, ret %d",
			current, last, ret);
	return retval;
}

/*
 * Check health of a specific health type. Note that if a thread has not yet
 * initialize its health subsystem or has quit, it's considered in a good
 * state.
 *
 * Return 0 if health is bad or else 1.
 */
int health_check_state(struct health_app *ha, int type)
{
	int retval = 1;
	struct health_state *state;

	assert(type < ha->nr_types);

	state_lock(ha);

	cds_list_for_each_entry(state, &ha->list, node) {
		int ret;

		if (state->type != type) {
			continue;
		}

		ret = validate_state(ha, state);
		if (!ret) {
			retval = 0;
			goto end;
		}
	}

	/* Check the global state since some state might not be visible anymore. */
	if (ha->flags[type] & HEALTH_ERROR) {
		retval = 0;
	}

end:
	state_unlock(ha);

	DBG("Health check for type %d is %s", (int) type,
			(retval == 0) ? "BAD" : "GOOD");
	return retval;
}

/*
 * Init health state.
 */
void health_register(struct health_app *ha, int type)
{
	assert(type < ha->nr_types);

	/* Init TLS state. */
	uatomic_set(&URCU_TLS(health_state).last, 0);
	uatomic_set(&URCU_TLS(health_state).last_time.tv_sec, 0);
	uatomic_set(&URCU_TLS(health_state).last_time.tv_nsec, 0);
	uatomic_set(&URCU_TLS(health_state).current, 0);
	uatomic_set(&URCU_TLS(health_state).flags, 0);
	uatomic_set(&URCU_TLS(health_state).type, type);

	/* Add it to the global TLS state list. */
	state_lock(ha);
	cds_list_add(&URCU_TLS(health_state).node, &ha->list);
	state_unlock(ha);
}

/*
 * Remove node from global list.
 */
void health_unregister(struct health_app *ha)
{
	state_lock(ha);
	/*
	 * On error, set the global_error_state since we are about to remove
	 * the node from the global list.
	 */
	if (uatomic_read(&URCU_TLS(health_state).flags) & HEALTH_ERROR) {
		uatomic_set(&ha->flags[URCU_TLS(health_state).type],
				HEALTH_ERROR);
	}
	cds_list_del(&URCU_TLS(health_state).node);
	state_unlock(ha);
}

/*
 * Initiliazie health check subsytem. This should be called before any health
 * register occurs.
 */
void health_init(struct health_app *ha)
{
	/*
	 * Get the maximum value between the default delta value and the TCP
	 * timeout with a safety net of the default health check delta.
	 */
	ha->time_delta.tv_sec = max_t(unsigned long,
			lttcomm_inet_tcp_timeout + DEFAULT_HEALTH_CHECK_DELTA_S,
			ha->time_delta.tv_sec);
	DBG("Health check time delta in seconds set to %lu",
		ha->time_delta.tv_sec);
}
Commit	Line	Data
	1	/*
	2	* Copyright (C) 2012 - David Goulet <dgoulet@efficios.com>
	3	* Copyright (C) 2013 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
	4	*
	5	* This program is free software; you can redistribute it and/or modify it
	6	* under the terms of the GNU General Public License, version 2 only, as
	7	* published by the Free Software Foundation.
	8	*
	9	* This program is distributed in the hope that it will be useful, but WITHOUT
	10	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
	11	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
	12	* more details.
	13	*
	14	* You should have received a copy of the GNU General Public License along with
	15	* this program; if not, write to the Free Software Foundation, Inc., 51
	16	* Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
	17	*/
	18
	19	#define _GNU_SOURCE
	20	#include <assert.h>
	21	#include <inttypes.h>
	22	#include <stdio.h>
	23	#include <stdlib.h>
	24	#include <time.h>
	25
	26	#include <common/defaults.h>
	27	#include <common/error.h>
	28	#include <common/macros.h>
	29	#include <common/sessiond-comm/inet.h>
	30
	31	#include "health.h"
	32
	33	/*
	34	* An application-specific error state for unregistered thread keeps
	35	* track of thread errors. A thread reporting a health error, normally
	36	* unregisters and quits. This makes the TLS health state not available
	37	* to the health_check_state() call so on unregister we update this
	38	* global error array so we can keep track of which thread was on error
	39	* if the TLS health state has been removed.
	40	*/
	41	struct health_app {
	42	/* List of health state, for each application thread */
	43	struct cds_list_head list;
	44	/*
	45	* This lock ensures that TLS memory used for the node and its
	46	* container structure don't get reclaimed after the TLS owner
	47	* thread exits until we have finished using it.
	48	*/
	49	pthread_mutex_t lock;
	50	int nr_types;
	51	struct timespec time_delta;
	52	/* Health flags containing thread type error state */
	53	enum health_flags *flags;
	54	};
	55
	56	/* Define TLS health state. */
	57	DEFINE_URCU_TLS(struct health_state, health_state);
	58
	59	struct health_app *health_app_create(int nr_types)
	60	{
	61	struct health_app *ha;
	62
	63	ha = zmalloc(sizeof(*ha));
	64	if (!ha) {
	65	return NULL;
	66	}
	67	ha->flags = zmalloc(sizeof(*ha->flags));
	68	if (!ha->flags) {
	69	goto error_flags;
	70	}
	71	CDS_INIT_LIST_HEAD(&ha->list);
	72	pthread_mutex_init(&ha->lock, NULL);
	73	ha->nr_types = nr_types;
	74	ha->time_delta.tv_sec = DEFAULT_HEALTH_CHECK_DELTA_S;
	75	ha->time_delta.tv_nsec = DEFAULT_HEALTH_CHECK_DELTA_NS;
	76	return ha;
	77
	78	error_flags:
	79	free(ha);
	80	return NULL;
	81	}
	82
	83	void health_app_destroy(struct health_app *ha)
	84	{
	85	free(ha->flags);
	86	free(ha);
	87	}
	88
	89	/*
	90	* Lock health state global list mutex.
	91	*/
	92	static void state_lock(struct health_app *ha)
	93	{
	94	pthread_mutex_lock(&ha->lock);
	95	}
	96
	97	/*
	98	* Unlock health state global list mutex.
	99	*/
	100	static void state_unlock(struct health_app *ha)
	101	{
	102	pthread_mutex_unlock(&ha->lock);
	103	}
	104
	105	/*
	106	* Set time difference in res from time_a and time_b.
	107	*/
	108	static void time_diff(const struct timespec *time_a,
	109	const struct timespec time_b, struct timespec res)
	110	{
	111	if (time_a->tv_nsec - time_b->tv_nsec < 0) {
	112	res->tv_sec = time_a->tv_sec - time_b->tv_sec - 1;
	113	res->tv_nsec = 1000000000L + time_a->tv_sec - time_b->tv_sec;
	114	} else {
	115	res->tv_sec = time_a->tv_sec - time_b->tv_sec;
	116	res->tv_nsec = time_a->tv_nsec - time_b->tv_nsec;
	117	}
	118	}
	119
	120	/*
	121	* Return true if time_a - time_b > diff, else false.
	122	*/
	123	static int time_diff_gt(const struct timespec *time_a,
	124	const struct timespec time_b, const struct timespec diff)
	125	{
	126	struct timespec res;
	127
	128	time_diff(time_a, time_b, &res);
	129	time_diff(&res, diff, &res);
	130
	131	if (res.tv_sec > 0) {
	132	return 1;
	133	} else if (res.tv_sec == 0 && res.tv_nsec > 0) {
	134	return 1;
	135	}
	136
	137	return 0;
	138	}
	139
	140	/*
	141	* Validate health state. Checks for the error flag or health conditions.
	142	*
	143	* Return 0 if health is bad or else 1.
	144	*/
	145	static int validate_state(struct health_app ha, struct health_state state)
	146	{
	147	int retval = 1, ret;
	148	unsigned long current, last;
	149	struct timespec current_time;
	150
	151	assert(state);
	152
	153	last = state->last;
	154	current = uatomic_read(&state->current);
	155
	156	ret = clock_gettime(CLOCK_MONOTONIC, &current_time);
	157	if (ret < 0) {
	158	PERROR("Error reading time\n");
	159	/* error */
	160	retval = 0;
	161	goto end;
	162	}
	163
	164	/*
	165	* Thread is in bad health if flag HEALTH_ERROR is set. It is also in bad
	166	* health if, after the delta delay has passed, its the progress counter
	167	* has not moved and it has NOT been waiting for a poll() call.
	168	*/
	169	if (uatomic_read(&state->flags) & HEALTH_ERROR) {
	170	retval = 0;
	171	goto end;
	172	}
	173
	174	/*
	175	* Initial condition need to update the last counter and sample time, but
	176	* should not check health in this initial case, because we don't know how
	177	* much time has passed.
	178	*/
	179	if (state->last_time.tv_sec == 0 && state->last_time.tv_nsec == 0) {
	180	/* update last counter and last sample time */
	181	state->last = current;
	182	memcpy(&state->last_time, &current_time, sizeof(current_time));
	183	} else {
	184	if (time_diff_gt(&current_time, &state->last_time,
	185	&ha->time_delta)) {
	186	if (current == last && !HEALTH_IS_IN_POLL(current)) {
	187	/* error */
	188	retval = 0;
	189	}
	190	/* update last counter and last sample time */
	191	state->last = current;
	192	memcpy(&state->last_time, &current_time, sizeof(current_time));
	193
	194	/* On error, stop right now and notify caller. */
	195	if (retval == 0) {
	196	goto end;
	197	}
	198	}
	199	}
	200
	201	end:
	202	DBG("Health state current %lu, last %lu, ret %d",
	203	current, last, ret);
	204	return retval;
	205	}
	206
	207	/*
	208	* Check health of a specific health type. Note that if a thread has not yet
	209	* initialize its health subsystem or has quit, it's considered in a good
	210	* state.
	211	*
	212	* Return 0 if health is bad or else 1.
	213	*/
	214	int health_check_state(struct health_app *ha, int type)
	215	{
	216	int retval = 1;
	217	struct health_state *state;
	218
	219	assert(type < ha->nr_types);
	220
	221	state_lock(ha);
	222
	223	cds_list_for_each_entry(state, &ha->list, node) {
	224	int ret;
	225
	226	if (state->type != type) {
	227	continue;
	228	}
	229
	230	ret = validate_state(ha, state);
	231	if (!ret) {
	232	retval = 0;
	233	goto end;
	234	}
	235	}
	236
	237	/* Check the global state since some state might not be visible anymore. */
	238	if (ha->flags[type] & HEALTH_ERROR) {
	239	retval = 0;
	240	}
	241
	242	end:
	243	state_unlock(ha);
	244
	245	DBG("Health check for type %d is %s", (int) type,
	246	(retval == 0) ? "BAD" : "GOOD");
	247	return retval;
	248	}
	249
	250	/*
	251	* Init health state.
	252	*/
	253	void health_register(struct health_app *ha, int type)
	254	{
	255	assert(type < ha->nr_types);
	256
	257	/* Init TLS state. */
	258	uatomic_set(&URCU_TLS(health_state).last, 0);
	259	uatomic_set(&URCU_TLS(health_state).last_time.tv_sec, 0);
	260	uatomic_set(&URCU_TLS(health_state).last_time.tv_nsec, 0);
	261	uatomic_set(&URCU_TLS(health_state).current, 0);
	262	uatomic_set(&URCU_TLS(health_state).flags, 0);
	263	uatomic_set(&URCU_TLS(health_state).type, type);
	264
	265	/* Add it to the global TLS state list. */
	266	state_lock(ha);
	267	cds_list_add(&URCU_TLS(health_state).node, &ha->list);
	268	state_unlock(ha);
	269	}
	270
	271	/*
	272	* Remove node from global list.
	273	*/
	274	void health_unregister(struct health_app *ha)
	275	{
	276	state_lock(ha);
	277	/*
	278	* On error, set the global_error_state since we are about to remove
	279	* the node from the global list.
	280	*/
	281	if (uatomic_read(&URCU_TLS(health_state).flags) & HEALTH_ERROR) {
	282	uatomic_set(&ha->flags[URCU_TLS(health_state).type],
	283	HEALTH_ERROR);
	284	}
	285	cds_list_del(&URCU_TLS(health_state).node);
	286	state_unlock(ha);
	287	}
	288
	289	/*
	290	* Initiliazie health check subsytem. This should be called before any health
	291	* register occurs.
	292	*/
	293	void health_init(struct health_app *ha)
	294	{
	295	/*
	296	* Get the maximum value between the default delta value and the TCP
	297	* timeout with a safety net of the default health check delta.
	298	*/
	299	ha->time_delta.tv_sec = max_t(unsigned long,
	300	lttcomm_inet_tcp_timeout + DEFAULT_HEALTH_CHECK_DELTA_S,
	301	ha->time_delta.tv_sec);
	302	DBG("Health check time delta in seconds set to %lu",
	303	ha->time_delta.tv_sec);
	304	}