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comparison src/stream/ngx_stream_upstream_least_conn_module.c @ 6115:61d7ae76647d

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Stream: port from NGINX+.
author Ruslan Ermilov <ru@nginx.com>
date Mon, 20 Apr 2015 13:05:11 +0300
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children 68c106e6fa0a
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6114:4a640716f4e2 6115:61d7ae76647d
1
2 /*
3 * Copyright (C) Maxim Dounin
4 * Copyright (C) Nginx, Inc.
5 */
6
7
8 #include <ngx_config.h>
9 #include <ngx_core.h>
10 #include <ngx_stream.h>
11
12
13 static ngx_int_t ngx_stream_upstream_init_least_conn_peer(
14 ngx_stream_session_t *s, ngx_stream_upstream_srv_conf_t *us);
15 static ngx_int_t ngx_stream_upstream_get_least_conn_peer(
16 ngx_peer_connection_t *pc, void *data);
17 static char *ngx_stream_upstream_least_conn(ngx_conf_t *cf, ngx_command_t *cmd,
18 void *conf);
19
20
21 static ngx_command_t ngx_stream_upstream_least_conn_commands[] = {
22
23 { ngx_string("least_conn"),
24 NGX_STREAM_UPS_CONF|NGX_CONF_NOARGS,
25 ngx_stream_upstream_least_conn,
26 0,
27 0,
28 NULL },
29
30 ngx_null_command
31 };
32
33
34 static ngx_stream_module_t ngx_stream_upstream_least_conn_module_ctx = {
35 NULL, /* create main configuration */
36 NULL, /* init main configuration */
37
38 NULL, /* create server configuration */
39 NULL, /* merge server configuration */
40 };
41
42
43 ngx_module_t ngx_stream_upstream_least_conn_module = {
44 NGX_MODULE_V1,
45 &ngx_stream_upstream_least_conn_module_ctx, /* module context */
46 ngx_stream_upstream_least_conn_commands, /* module directives */
47 NGX_STREAM_MODULE, /* module type */
48 NULL, /* init master */
49 NULL, /* init module */
50 NULL, /* init process */
51 NULL, /* init thread */
52 NULL, /* exit thread */
53 NULL, /* exit process */
54 NULL, /* exit master */
55 NGX_MODULE_V1_PADDING
56 };
57
58
59 static ngx_int_t
60 ngx_stream_upstream_init_least_conn(ngx_conf_t *cf,
61 ngx_stream_upstream_srv_conf_t *us)
62 {
63 ngx_log_debug0(NGX_LOG_DEBUG_STREAM, cf->log, 0,
64 "init least conn");
65
66 if (ngx_stream_upstream_init_round_robin(cf, us) != NGX_OK) {
67 return NGX_ERROR;
68 }
69
70 us->peer.init = ngx_stream_upstream_init_least_conn_peer;
71
72 return NGX_OK;
73 }
74
75
76 static ngx_int_t
77 ngx_stream_upstream_init_least_conn_peer(ngx_stream_session_t *s,
78 ngx_stream_upstream_srv_conf_t *us)
79 {
80 ngx_log_debug0(NGX_LOG_DEBUG_STREAM, s->connection->log, 0,
81 "init least conn peer");
82
83 if (ngx_stream_upstream_init_round_robin_peer(s, us) != NGX_OK) {
84 return NGX_ERROR;
85 }
86
87 s->upstream->peer.get = ngx_stream_upstream_get_least_conn_peer;
88
89 return NGX_OK;
90 }
91
92
93 static ngx_int_t
94 ngx_stream_upstream_get_least_conn_peer(ngx_peer_connection_t *pc, void *data)
95 {
96 ngx_stream_upstream_rr_peer_data_t *rrp = data;
97
98 time_t now;
99 uintptr_t m;
100 ngx_int_t rc, total;
101 ngx_uint_t i, n, p, many;
102 ngx_stream_upstream_rr_peer_t *peer, *best;
103 ngx_stream_upstream_rr_peers_t *peers;
104
105 ngx_log_debug1(NGX_LOG_DEBUG_STREAM, pc->log, 0,
106 "get least conn peer, try: %ui", pc->tries);
107
108 if (rrp->peers->single) {
109 return ngx_stream_upstream_get_round_robin_peer(pc, rrp);
110 }
111
112 pc->connection = NULL;
113
114 now = ngx_time();
115
116 peers = rrp->peers;
117
118 ngx_stream_upstream_rr_peers_wlock(peers);
119
120 best = NULL;
121 total = 0;
122
123 #if (NGX_SUPPRESS_WARN)
124 many = 0;
125 p = 0;
126 #endif
127
128 for (peer = peers->peer, i = 0;
129 peer;
130 peer = peer->next, i++)
131 {
132
133 n = i / (8 * sizeof(uintptr_t));
134 m = (uintptr_t) 1 << i % (8 * sizeof(uintptr_t));
135
136 if (rrp->tried[n] & m) {
137 continue;
138 }
139
140 if (peer->down) {
141 continue;
142 }
143
144 if (peer->max_fails
145 && peer->fails >= peer->max_fails
146 && now - peer->checked <= peer->fail_timeout)
147 {
148 continue;
149 }
150
151 /*
152 * select peer with least number of connections; if there are
153 * multiple peers with the same number of connections, select
154 * based on round-robin
155 */
156
157 if (best == NULL
158 || peer->conns * best->weight < best->conns * peer->weight)
159 {
160 best = peer;
161 many = 0;
162 p = i;
163
164 } else if (peer->conns * best->weight == best->conns * peer->weight) {
165 many = 1;
166 }
167 }
168
169 if (best == NULL) {
170 ngx_log_debug0(NGX_LOG_DEBUG_STREAM, pc->log, 0,
171 "get least conn peer, no peer found");
172
173 goto failed;
174 }
175
176 if (many) {
177 ngx_log_debug0(NGX_LOG_DEBUG_STREAM, pc->log, 0,
178 "get least conn peer, many");
179
180 for (peer = best, i = p;
181 peer;
182 peer = peer->next, i++)
183 {
184 n = i / (8 * sizeof(uintptr_t));
185 m = (uintptr_t) 1 << i % (8 * sizeof(uintptr_t));
186
187 if (rrp->tried[n] & m) {
188 continue;
189 }
190
191 if (peer->down) {
192 continue;
193 }
194
195 if (peer->conns * best->weight != best->conns * peer->weight) {
196 continue;
197 }
198
199 if (peer->max_fails
200 && peer->fails >= peer->max_fails
201 && now - peer->checked <= peer->fail_timeout)
202 {
203 continue;
204 }
205
206 peer->current_weight += peer->effective_weight;
207 total += peer->effective_weight;
208
209 if (peer->effective_weight < peer->weight) {
210 peer->effective_weight++;
211 }
212
213 if (peer->current_weight > best->current_weight) {
214 best = peer;
215 p = i;
216 }
217 }
218 }
219
220 best->current_weight -= total;
221
222 if (now - best->checked > best->fail_timeout) {
223 best->checked = now;
224 }
225
226 pc->sockaddr = best->sockaddr;
227 pc->socklen = best->socklen;
228 pc->name = &best->name;
229
230 best->conns++;
231
232 rrp->current = best;
233
234 n = p / (8 * sizeof(uintptr_t));
235 m = (uintptr_t) 1 << p % (8 * sizeof(uintptr_t));
236
237 rrp->tried[n] |= m;
238
239 ngx_stream_upstream_rr_peers_unlock(peers);
240
241 return NGX_OK;
242
243 failed:
244
245 if (peers->next) {
246 ngx_log_debug0(NGX_LOG_DEBUG_STREAM, pc->log, 0,
247 "get least conn peer, backup servers");
248
249 rrp->peers = peers->next;
250
251 n = (rrp->peers->number + (8 * sizeof(uintptr_t) - 1))
252 / (8 * sizeof(uintptr_t));
253
254 for (i = 0; i < n; i++) {
255 rrp->tried[i] = 0;
256 }
257
258 ngx_stream_upstream_rr_peers_unlock(peers);
259
260 rc = ngx_stream_upstream_get_least_conn_peer(pc, rrp);
261
262 if (rc != NGX_BUSY) {
263 return rc;
264 }
265
266 ngx_stream_upstream_rr_peers_wlock(peers);
267 }
268
269 /* all peers failed, mark them as live for quick recovery */
270
271 for (peer = peers->peer; peer; peer = peer->next) {
272 peer->fails = 0;
273 }
274
275 ngx_stream_upstream_rr_peers_unlock(peers);
276
277 pc->name = peers->name;
278
279 return NGX_BUSY;
280 }
281
282
283 static char *
284 ngx_stream_upstream_least_conn(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
285 {
286 ngx_stream_upstream_srv_conf_t *uscf;
287
288 uscf = ngx_stream_conf_get_module_srv_conf(cf, ngx_stream_upstream_module);
289
290 if (uscf->peer.init_upstream) {
291 ngx_conf_log_error(NGX_LOG_WARN, cf, 0,
292 "load balancing method redefined");
293 }
294
295 uscf->peer.init_upstream = ngx_stream_upstream_init_least_conn;
296
297 uscf->flags = NGX_STREAM_UPSTREAM_CREATE
298 |NGX_STREAM_UPSTREAM_WEIGHT
299 |NGX_STREAM_UPSTREAM_MAX_FAILS
300 |NGX_STREAM_UPSTREAM_FAIL_TIMEOUT
301 |NGX_STREAM_UPSTREAM_DOWN
302 |NGX_STREAM_UPSTREAM_BACKUP;
303
304 return NGX_CONF_OK;
305 }