X-Git-Url: https://git.lttng.org/?p=lttng-tools.git;a=blobdiff_plain;f=src%2Fcommon%2Fhealth%2Fhealth.cpp;fp=src%2Fcommon%2Fhealth%2Fhealth.cpp;h=8a07e642607cb6cb401a57c845043ca63870f97e;hp=0000000000000000000000000000000000000000;hb=8784a4d054e8bfe27af0581fc9441c64a52b1074;hpb=6dca8ba7dec3b31acb7b43f5e4431676acf4e664 diff --git a/src/common/health/health.cpp b/src/common/health/health.cpp new file mode 100644 index 000000000..8a07e6426 --- /dev/null +++ b/src/common/health/health.cpp @@ -0,0 +1,295 @@ +/* + * Copyright (C) 2012 David Goulet + * Copyright (C) 2013 Mathieu Desnoyers + * + * SPDX-License-Identifier: GPL-2.0-only + * + */ + +#define _LGPL_SOURCE +#include +#include +#include +#include +#include + +#include +#include +#include +#include + +#include + +/* + * 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); + +/* + * Initialize health check subsytem. + */ +static +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 = std::max( + 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); +} + +struct health_app *health_app_create(int nr_types) +{ + struct health_app *ha; + + ha = (health_app *) zmalloc(sizeof(*ha)); + if (!ha) { + return NULL; + } + ha->flags = (health_flags *) zmalloc(sizeof(*ha->flags) * nr_types); + 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; + health_init(ha); + 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; + + LTTNG_ASSERT(state); + + last = state->last; + current = uatomic_read(&state->current); + + ret = lttng_clock_gettime(CLOCK_MONOTONIC, ¤t_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, ¤t_time, sizeof(current_time)); + } else { + if (time_diff_gt(¤t_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, ¤t_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; + + LTTNG_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) +{ + LTTNG_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, (health_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); +}