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44a5e5eb DG |
1 | /* |
2 | * Copyright (C) 2012 - David Goulet <dgoulet@efficios.com> | |
3 | * | |
4 | * This program is free software; you can redistribute it and/or modify it | |
5 | * under the terms of the GNU General Public License, version 2 only, as | |
6 | * published by the Free Software Foundation. | |
7 | * | |
8 | * This program is distributed in the hope that it will be useful, but WITHOUT | |
9 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
10 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for | |
11 | * more details. | |
12 | * | |
13 | * You should have received a copy of the GNU General Public License along with | |
14 | * this program; if not, write to the Free Software Foundation, Inc., 51 | |
15 | * Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. | |
16 | */ | |
17 | ||
18 | #define _GNU_SOURCE | |
19 | #include <assert.h> | |
20 | #include <inttypes.h> | |
21 | #include <stdio.h> | |
22 | #include <stdlib.h> | |
8809eec0 | 23 | #include <time.h> |
44a5e5eb | 24 | |
8809eec0 | 25 | #include <common/defaults.h> |
44a5e5eb DG |
26 | #include <common/error.h> |
27 | ||
28 | #include "health.h" | |
29 | ||
8809eec0 MD |
30 | static const struct timespec time_delta = { |
31 | .tv_sec = DEFAULT_HEALTH_CHECK_DELTA_S, | |
32 | .tv_nsec = DEFAULT_HEALTH_CHECK_DELTA_NS, | |
33 | }; | |
34 | ||
927ca06a DG |
35 | /* Define TLS health state. */ |
36 | DEFINE_URCU_TLS(struct health_state, health_state); | |
37 | ||
38 | /* | |
39 | * It ensures that TLS memory used for the node and its container structure | |
40 | * don't get reclaimed after the TLS owner thread exits until we have finished | |
41 | * using it. | |
42 | */ | |
43 | static pthread_mutex_t health_mutex = PTHREAD_MUTEX_INITIALIZER; | |
44 | ||
45 | static struct health_tls_state_list health_state_list = { | |
46 | .head = CDS_LIST_HEAD_INIT(health_state_list.head), | |
47 | }; | |
48 | ||
49 | /* | |
50 | * This keeps track of the error state for unregistered thread. A thread | |
51 | * reporting a health error, normally unregisters and quits. This makes the TLS | |
52 | * health state not available to the health_check_state() call so on unregister | |
53 | * we update this global error array so we can keep track of which thread was | |
54 | * on error if the TLS health state has been removed. | |
55 | */ | |
56 | static enum health_flags global_error_state[HEALTH_NUM_TYPE]; | |
57 | ||
58 | /* | |
59 | * Lock health state global list mutex. | |
60 | */ | |
61 | static void state_lock(void) | |
62 | { | |
63 | pthread_mutex_lock(&health_mutex); | |
64 | } | |
65 | ||
66 | /* | |
67 | * Unlock health state global list mutex. | |
68 | */ | |
69 | static void state_unlock(void) | |
70 | { | |
71 | pthread_mutex_unlock(&health_mutex); | |
72 | } | |
73 | ||
8809eec0 MD |
74 | /* |
75 | * Set time difference in res from time_a and time_b. | |
76 | */ | |
77 | static void time_diff(const struct timespec *time_a, | |
78 | const struct timespec *time_b, struct timespec *res) | |
79 | { | |
80 | if (time_a->tv_nsec - time_b->tv_nsec < 0) { | |
81 | res->tv_sec = time_a->tv_sec - time_b->tv_sec - 1; | |
82 | res->tv_nsec = 1000000000L + time_a->tv_sec - time_b->tv_sec; | |
83 | } else { | |
84 | res->tv_sec = time_a->tv_sec - time_b->tv_sec; | |
931a97e5 | 85 | res->tv_nsec = time_a->tv_nsec - time_b->tv_nsec; |
8809eec0 MD |
86 | } |
87 | } | |
88 | ||
89 | /* | |
90 | * Return true if time_a - time_b > diff, else false. | |
91 | */ | |
92 | static int time_diff_gt(const struct timespec *time_a, | |
93 | const struct timespec *time_b, const struct timespec *diff) | |
94 | { | |
95 | struct timespec res; | |
96 | ||
97 | time_diff(time_a, time_b, &res); | |
98 | time_diff(&res, diff, &res); | |
99 | ||
100 | if (res.tv_sec > 0) { | |
101 | return 1; | |
102 | } else if (res.tv_sec == 0 && res.tv_nsec > 0) { | |
103 | return 1; | |
104 | } | |
105 | ||
106 | return 0; | |
107 | } | |
108 | ||
44a5e5eb | 109 | /* |
927ca06a DG |
110 | * Health mutex MUST be held across use of the returned struct health_state to |
111 | * provide existence guarantee. | |
112 | * | |
113 | * Return the health_state object or NULL if not found. | |
114 | */ | |
115 | static struct health_state *find_health_state(enum health_type type) | |
116 | { | |
117 | struct health_state *state; | |
118 | ||
119 | /* Find the right health state in the global TLS list. */ | |
120 | cds_list_for_each_entry(state, &health_state_list.head, node) { | |
121 | if (state->type == type) { | |
122 | return state; | |
123 | } | |
124 | } | |
125 | ||
126 | return NULL; | |
127 | } | |
128 | ||
129 | /* | |
130 | * Check health of a specific health type. Note that if a thread has not yet | |
131 | * initialize its health subsystem or has quit, it's considered in a good | |
132 | * state. | |
44a5e5eb DG |
133 | * |
134 | * Return 0 if health is bad or else 1. | |
135 | */ | |
927ca06a | 136 | int health_check_state(enum health_type type) |
44a5e5eb | 137 | { |
8809eec0 | 138 | int retval = 1, ret; |
139ac872 | 139 | unsigned long current, last; |
8809eec0 | 140 | struct timespec current_time; |
927ca06a DG |
141 | struct health_state *state; |
142 | ||
143 | assert(type < HEALTH_NUM_TYPE); | |
44a5e5eb | 144 | |
927ca06a DG |
145 | state_lock(); |
146 | ||
147 | state = find_health_state(type); | |
148 | if (!state) { | |
149 | /* Check the global state since the state is not visiable anymore. */ | |
150 | if (global_error_state[type] & HEALTH_ERROR) { | |
151 | retval = 0; | |
152 | } | |
153 | goto not_found; | |
154 | } | |
44a5e5eb | 155 | |
139ac872 | 156 | last = state->last; |
44a5e5eb | 157 | current = uatomic_read(&state->current); |
44a5e5eb | 158 | |
8809eec0 | 159 | ret = clock_gettime(CLOCK_MONOTONIC, ¤t_time); |
931a97e5 | 160 | if (ret < 0) { |
8809eec0 | 161 | PERROR("Error reading time\n"); |
139ac872 | 162 | /* error */ |
8809eec0 MD |
163 | retval = 0; |
164 | goto end; | |
44a5e5eb DG |
165 | } |
166 | ||
8809eec0 MD |
167 | /* |
168 | * Thread is in bad health if flag HEALTH_ERROR is set. It is also in bad | |
169 | * health if, after the delta delay has passed, its the progress counter | |
170 | * has not moved and it has NOT been waiting for a poll() call. | |
171 | */ | |
172 | if (uatomic_read(&state->flags) & HEALTH_ERROR) { | |
173 | retval = 0; | |
174 | goto end; | |
175 | } | |
44a5e5eb | 176 | |
139ac872 | 177 | /* |
8809eec0 MD |
178 | * Initial condition need to update the last counter and sample time, but |
179 | * should not check health in this initial case, because we don't know how | |
180 | * much time has passed. | |
139ac872 | 181 | */ |
8809eec0 MD |
182 | if (state->last_time.tv_sec == 0 && state->last_time.tv_nsec == 0) { |
183 | /* update last counter and last sample time */ | |
184 | state->last = current; | |
185 | memcpy(&state->last_time, ¤t_time, sizeof(current_time)); | |
186 | } else { | |
187 | if (time_diff_gt(¤t_time, &state->last_time, &time_delta)) { | |
188 | if (current == last && !HEALTH_IS_IN_POLL(current)) { | |
189 | /* error */ | |
190 | retval = 0; | |
191 | } | |
192 | /* update last counter and last sample time */ | |
193 | state->last = current; | |
194 | memcpy(&state->last_time, ¤t_time, sizeof(current_time)); | |
195 | } | |
196 | } | |
197 | ||
198 | end: | |
77c7c900 | 199 | DBG("Health state current %lu, last %lu, ret %d", |
8809eec0 | 200 | current, last, ret); |
927ca06a DG |
201 | not_found: |
202 | state_unlock(); | |
139ac872 | 203 | |
8809eec0 | 204 | return retval; |
44a5e5eb | 205 | } |
927ca06a DG |
206 | |
207 | /* | |
208 | * Init health state. | |
209 | */ | |
210 | void health_register(enum health_type type) | |
211 | { | |
212 | struct health_state *state; | |
213 | ||
214 | assert(type < HEALTH_NUM_TYPE); | |
215 | ||
216 | /* Init TLS state. */ | |
217 | uatomic_set(&URCU_TLS(health_state).last, 0); | |
218 | uatomic_set(&URCU_TLS(health_state).last_time.tv_sec, 0); | |
219 | uatomic_set(&URCU_TLS(health_state).last_time.tv_nsec, 0); | |
220 | uatomic_set(&URCU_TLS(health_state).current, 0); | |
221 | uatomic_set(&URCU_TLS(health_state).flags, 0); | |
222 | uatomic_set(&URCU_TLS(health_state).type, type); | |
223 | ||
224 | /* Add it to the global TLS state list. */ | |
225 | state_lock(); | |
226 | state = find_health_state(type); | |
227 | /* | |
228 | * Duplicates are not accepted, since lookups don't handle them at the | |
229 | * moment. | |
230 | */ | |
231 | assert(!state); | |
232 | ||
233 | cds_list_add(&URCU_TLS(health_state).node, &health_state_list.head); | |
234 | state_unlock(); | |
235 | } | |
236 | ||
237 | /* | |
238 | * Remove node from global list. | |
239 | */ | |
240 | void health_unregister(void) | |
241 | { | |
242 | state_lock(); | |
243 | /* | |
244 | * On error, set the global_error_state since we are about to remove | |
245 | * the node from the global list. | |
246 | */ | |
247 | if (uatomic_read(&URCU_TLS(health_state).flags) & HEALTH_ERROR) { | |
248 | uatomic_set(&global_error_state[URCU_TLS(health_state).type], | |
249 | HEALTH_ERROR); | |
250 | } | |
251 | cds_list_del(&URCU_TLS(health_state).node); | |
252 | state_unlock(); | |
253 | } |