Mercurial > hg > nginx
view src/http/modules/ngx_http_upstream_hash_module.c @ 7670:ccb5ff87ab3e
Cache: introduced min_free cache clearing.
Clearing cache based on free space left on a file system is
expected to allow better disk utilization in some cases, notably
when disk space might be also used for something other than nginx
cache (including nginx own temporary files) and while loading
cache (when cache size might be inaccurate for a while, effectively
disabling max_size cache clearing).
Based on a patch by Adam Bambuch.
author | Maxim Dounin <mdounin@mdounin.ru> |
---|---|
date | Mon, 22 Jun 2020 18:03:00 +0300 |
parents | d964b0aee8e7 |
children |
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/* * Copyright (C) Roman Arutyunyan * Copyright (C) Nginx, Inc. */ #include <ngx_config.h> #include <ngx_core.h> #include <ngx_http.h> typedef struct { uint32_t hash; ngx_str_t *server; } ngx_http_upstream_chash_point_t; typedef struct { ngx_uint_t number; ngx_http_upstream_chash_point_t point[1]; } ngx_http_upstream_chash_points_t; typedef struct { ngx_http_complex_value_t key; ngx_http_upstream_chash_points_t *points; } ngx_http_upstream_hash_srv_conf_t; typedef struct { /* the round robin data must be first */ ngx_http_upstream_rr_peer_data_t rrp; ngx_http_upstream_hash_srv_conf_t *conf; ngx_str_t key; ngx_uint_t tries; ngx_uint_t rehash; uint32_t hash; ngx_event_get_peer_pt get_rr_peer; } ngx_http_upstream_hash_peer_data_t; static ngx_int_t ngx_http_upstream_init_hash(ngx_conf_t *cf, ngx_http_upstream_srv_conf_t *us); static ngx_int_t ngx_http_upstream_init_hash_peer(ngx_http_request_t *r, ngx_http_upstream_srv_conf_t *us); static ngx_int_t ngx_http_upstream_get_hash_peer(ngx_peer_connection_t *pc, void *data); static ngx_int_t ngx_http_upstream_init_chash(ngx_conf_t *cf, ngx_http_upstream_srv_conf_t *us); static int ngx_libc_cdecl ngx_http_upstream_chash_cmp_points(const void *one, const void *two); static ngx_uint_t ngx_http_upstream_find_chash_point( ngx_http_upstream_chash_points_t *points, uint32_t hash); static ngx_int_t ngx_http_upstream_init_chash_peer(ngx_http_request_t *r, ngx_http_upstream_srv_conf_t *us); static ngx_int_t ngx_http_upstream_get_chash_peer(ngx_peer_connection_t *pc, void *data); static void *ngx_http_upstream_hash_create_conf(ngx_conf_t *cf); static char *ngx_http_upstream_hash(ngx_conf_t *cf, ngx_command_t *cmd, void *conf); static ngx_command_t ngx_http_upstream_hash_commands[] = { { ngx_string("hash"), NGX_HTTP_UPS_CONF|NGX_CONF_TAKE12, ngx_http_upstream_hash, NGX_HTTP_SRV_CONF_OFFSET, 0, NULL }, ngx_null_command }; static ngx_http_module_t ngx_http_upstream_hash_module_ctx = { NULL, /* preconfiguration */ NULL, /* postconfiguration */ NULL, /* create main configuration */ NULL, /* init main configuration */ ngx_http_upstream_hash_create_conf, /* create server configuration */ NULL, /* merge server configuration */ NULL, /* create location configuration */ NULL /* merge location configuration */ }; ngx_module_t ngx_http_upstream_hash_module = { NGX_MODULE_V1, &ngx_http_upstream_hash_module_ctx, /* module context */ ngx_http_upstream_hash_commands, /* module directives */ NGX_HTTP_MODULE, /* module type */ NULL, /* init master */ NULL, /* init module */ NULL, /* init process */ NULL, /* init thread */ NULL, /* exit thread */ NULL, /* exit process */ NULL, /* exit master */ NGX_MODULE_V1_PADDING }; static ngx_int_t ngx_http_upstream_init_hash(ngx_conf_t *cf, ngx_http_upstream_srv_conf_t *us) { if (ngx_http_upstream_init_round_robin(cf, us) != NGX_OK) { return NGX_ERROR; } us->peer.init = ngx_http_upstream_init_hash_peer; return NGX_OK; } static ngx_int_t ngx_http_upstream_init_hash_peer(ngx_http_request_t *r, ngx_http_upstream_srv_conf_t *us) { ngx_http_upstream_hash_srv_conf_t *hcf; ngx_http_upstream_hash_peer_data_t *hp; hp = ngx_palloc(r->pool, sizeof(ngx_http_upstream_hash_peer_data_t)); if (hp == NULL) { return NGX_ERROR; } r->upstream->peer.data = &hp->rrp; if (ngx_http_upstream_init_round_robin_peer(r, us) != NGX_OK) { return NGX_ERROR; } r->upstream->peer.get = ngx_http_upstream_get_hash_peer; hcf = ngx_http_conf_upstream_srv_conf(us, ngx_http_upstream_hash_module); if (ngx_http_complex_value(r, &hcf->key, &hp->key) != NGX_OK) { return NGX_ERROR; } ngx_log_debug1(NGX_LOG_DEBUG_HTTP, r->connection->log, 0, "upstream hash key:\"%V\"", &hp->key); hp->conf = hcf; hp->tries = 0; hp->rehash = 0; hp->hash = 0; hp->get_rr_peer = ngx_http_upstream_get_round_robin_peer; return NGX_OK; } static ngx_int_t ngx_http_upstream_get_hash_peer(ngx_peer_connection_t *pc, void *data) { ngx_http_upstream_hash_peer_data_t *hp = data; time_t now; u_char buf[NGX_INT_T_LEN]; size_t size; uint32_t hash; ngx_int_t w; uintptr_t m; ngx_uint_t n, p; ngx_http_upstream_rr_peer_t *peer; ngx_log_debug1(NGX_LOG_DEBUG_HTTP, pc->log, 0, "get hash peer, try: %ui", pc->tries); ngx_http_upstream_rr_peers_rlock(hp->rrp.peers); if (hp->tries > 20 || hp->rrp.peers->single || hp->key.len == 0) { ngx_http_upstream_rr_peers_unlock(hp->rrp.peers); return hp->get_rr_peer(pc, &hp->rrp); } now = ngx_time(); pc->cached = 0; pc->connection = NULL; for ( ;; ) { /* * Hash expression is compatible with Cache::Memcached: * ((crc32([REHASH] KEY) >> 16) & 0x7fff) + PREV_HASH * with REHASH omitted at the first iteration. */ ngx_crc32_init(hash); if (hp->rehash > 0) { size = ngx_sprintf(buf, "%ui", hp->rehash) - buf; ngx_crc32_update(&hash, buf, size); } ngx_crc32_update(&hash, hp->key.data, hp->key.len); ngx_crc32_final(hash); hash = (hash >> 16) & 0x7fff; hp->hash += hash; hp->rehash++; w = hp->hash % hp->rrp.peers->total_weight; peer = hp->rrp.peers->peer; p = 0; while (w >= peer->weight) { w -= peer->weight; peer = peer->next; p++; } n = p / (8 * sizeof(uintptr_t)); m = (uintptr_t) 1 << p % (8 * sizeof(uintptr_t)); if (hp->rrp.tried[n] & m) { goto next; } ngx_http_upstream_rr_peer_lock(hp->rrp.peers, peer); ngx_log_debug2(NGX_LOG_DEBUG_HTTP, pc->log, 0, "get hash peer, value:%uD, peer:%ui", hp->hash, p); if (peer->down) { ngx_http_upstream_rr_peer_unlock(hp->rrp.peers, peer); goto next; } if (peer->max_fails && peer->fails >= peer->max_fails && now - peer->checked <= peer->fail_timeout) { ngx_http_upstream_rr_peer_unlock(hp->rrp.peers, peer); goto next; } if (peer->max_conns && peer->conns >= peer->max_conns) { ngx_http_upstream_rr_peer_unlock(hp->rrp.peers, peer); goto next; } break; next: if (++hp->tries > 20) { ngx_http_upstream_rr_peers_unlock(hp->rrp.peers); return hp->get_rr_peer(pc, &hp->rrp); } } hp->rrp.current = peer; pc->sockaddr = peer->sockaddr; pc->socklen = peer->socklen; pc->name = &peer->name; peer->conns++; if (now - peer->checked > peer->fail_timeout) { peer->checked = now; } ngx_http_upstream_rr_peer_unlock(hp->rrp.peers, peer); ngx_http_upstream_rr_peers_unlock(hp->rrp.peers); hp->rrp.tried[n] |= m; return NGX_OK; } static ngx_int_t ngx_http_upstream_init_chash(ngx_conf_t *cf, ngx_http_upstream_srv_conf_t *us) { u_char *host, *port, c; size_t host_len, port_len, size; uint32_t hash, base_hash; ngx_str_t *server; ngx_uint_t npoints, i, j; ngx_http_upstream_rr_peer_t *peer; ngx_http_upstream_rr_peers_t *peers; ngx_http_upstream_chash_points_t *points; ngx_http_upstream_hash_srv_conf_t *hcf; union { uint32_t value; u_char byte[4]; } prev_hash; if (ngx_http_upstream_init_round_robin(cf, us) != NGX_OK) { return NGX_ERROR; } us->peer.init = ngx_http_upstream_init_chash_peer; peers = us->peer.data; npoints = peers->total_weight * 160; size = sizeof(ngx_http_upstream_chash_points_t) + sizeof(ngx_http_upstream_chash_point_t) * (npoints - 1); points = ngx_palloc(cf->pool, size); if (points == NULL) { return NGX_ERROR; } points->number = 0; for (peer = peers->peer; peer; peer = peer->next) { server = &peer->server; /* * Hash expression is compatible with Cache::Memcached::Fast: * crc32(HOST \0 PORT PREV_HASH). */ if (server->len >= 5 && ngx_strncasecmp(server->data, (u_char *) "unix:", 5) == 0) { host = server->data + 5; host_len = server->len - 5; port = NULL; port_len = 0; goto done; } for (j = 0; j < server->len; j++) { c = server->data[server->len - j - 1]; if (c == ':') { host = server->data; host_len = server->len - j - 1; port = server->data + server->len - j; port_len = j; goto done; } if (c < '0' || c > '9') { break; } } host = server->data; host_len = server->len; port = NULL; port_len = 0; done: ngx_crc32_init(base_hash); ngx_crc32_update(&base_hash, host, host_len); ngx_crc32_update(&base_hash, (u_char *) "", 1); ngx_crc32_update(&base_hash, port, port_len); prev_hash.value = 0; npoints = peer->weight * 160; for (j = 0; j < npoints; j++) { hash = base_hash; ngx_crc32_update(&hash, prev_hash.byte, 4); ngx_crc32_final(hash); points->point[points->number].hash = hash; points->point[points->number].server = server; points->number++; #if (NGX_HAVE_LITTLE_ENDIAN) prev_hash.value = hash; #else prev_hash.byte[0] = (u_char) (hash & 0xff); prev_hash.byte[1] = (u_char) ((hash >> 8) & 0xff); prev_hash.byte[2] = (u_char) ((hash >> 16) & 0xff); prev_hash.byte[3] = (u_char) ((hash >> 24) & 0xff); #endif } } ngx_qsort(points->point, points->number, sizeof(ngx_http_upstream_chash_point_t), ngx_http_upstream_chash_cmp_points); for (i = 0, j = 1; j < points->number; j++) { if (points->point[i].hash != points->point[j].hash) { points->point[++i] = points->point[j]; } } points->number = i + 1; hcf = ngx_http_conf_upstream_srv_conf(us, ngx_http_upstream_hash_module); hcf->points = points; return NGX_OK; } static int ngx_libc_cdecl ngx_http_upstream_chash_cmp_points(const void *one, const void *two) { ngx_http_upstream_chash_point_t *first = (ngx_http_upstream_chash_point_t *) one; ngx_http_upstream_chash_point_t *second = (ngx_http_upstream_chash_point_t *) two; if (first->hash < second->hash) { return -1; } else if (first->hash > second->hash) { return 1; } else { return 0; } } static ngx_uint_t ngx_http_upstream_find_chash_point(ngx_http_upstream_chash_points_t *points, uint32_t hash) { ngx_uint_t i, j, k; ngx_http_upstream_chash_point_t *point; /* find first point >= hash */ point = &points->point[0]; i = 0; j = points->number; while (i < j) { k = (i + j) / 2; if (hash > point[k].hash) { i = k + 1; } else if (hash < point[k].hash) { j = k; } else { return k; } } return i; } static ngx_int_t ngx_http_upstream_init_chash_peer(ngx_http_request_t *r, ngx_http_upstream_srv_conf_t *us) { uint32_t hash; ngx_http_upstream_hash_srv_conf_t *hcf; ngx_http_upstream_hash_peer_data_t *hp; if (ngx_http_upstream_init_hash_peer(r, us) != NGX_OK) { return NGX_ERROR; } r->upstream->peer.get = ngx_http_upstream_get_chash_peer; hp = r->upstream->peer.data; hcf = ngx_http_conf_upstream_srv_conf(us, ngx_http_upstream_hash_module); hash = ngx_crc32_long(hp->key.data, hp->key.len); ngx_http_upstream_rr_peers_rlock(hp->rrp.peers); hp->hash = ngx_http_upstream_find_chash_point(hcf->points, hash); ngx_http_upstream_rr_peers_unlock(hp->rrp.peers); return NGX_OK; } static ngx_int_t ngx_http_upstream_get_chash_peer(ngx_peer_connection_t *pc, void *data) { ngx_http_upstream_hash_peer_data_t *hp = data; time_t now; intptr_t m; ngx_str_t *server; ngx_int_t total; ngx_uint_t i, n, best_i; ngx_http_upstream_rr_peer_t *peer, *best; ngx_http_upstream_chash_point_t *point; ngx_http_upstream_chash_points_t *points; ngx_http_upstream_hash_srv_conf_t *hcf; ngx_log_debug1(NGX_LOG_DEBUG_HTTP, pc->log, 0, "get consistent hash peer, try: %ui", pc->tries); ngx_http_upstream_rr_peers_wlock(hp->rrp.peers); if (hp->tries > 20 || hp->rrp.peers->single || hp->key.len == 0) { ngx_http_upstream_rr_peers_unlock(hp->rrp.peers); return hp->get_rr_peer(pc, &hp->rrp); } pc->cached = 0; pc->connection = NULL; now = ngx_time(); hcf = hp->conf; points = hcf->points; point = &points->point[0]; for ( ;; ) { server = point[hp->hash % points->number].server; ngx_log_debug2(NGX_LOG_DEBUG_HTTP, pc->log, 0, "consistent hash peer:%uD, server:\"%V\"", hp->hash, server); best = NULL; best_i = 0; total = 0; for (peer = hp->rrp.peers->peer, i = 0; peer; peer = peer->next, i++) { n = i / (8 * sizeof(uintptr_t)); m = (uintptr_t) 1 << i % (8 * sizeof(uintptr_t)); if (hp->rrp.tried[n] & m) { continue; } if (peer->down) { continue; } if (peer->max_fails && peer->fails >= peer->max_fails && now - peer->checked <= peer->fail_timeout) { continue; } if (peer->max_conns && peer->conns >= peer->max_conns) { continue; } if (peer->server.len != server->len || ngx_strncmp(peer->server.data, server->data, server->len) != 0) { continue; } peer->current_weight += peer->effective_weight; total += peer->effective_weight; if (peer->effective_weight < peer->weight) { peer->effective_weight++; } if (best == NULL || peer->current_weight > best->current_weight) { best = peer; best_i = i; } } if (best) { best->current_weight -= total; goto found; } hp->hash++; hp->tries++; if (hp->tries > 20) { ngx_http_upstream_rr_peers_unlock(hp->rrp.peers); return hp->get_rr_peer(pc, &hp->rrp); } } found: hp->rrp.current = best; pc->sockaddr = best->sockaddr; pc->socklen = best->socklen; pc->name = &best->name; best->conns++; if (now - best->checked > best->fail_timeout) { best->checked = now; } ngx_http_upstream_rr_peers_unlock(hp->rrp.peers); n = best_i / (8 * sizeof(uintptr_t)); m = (uintptr_t) 1 << best_i % (8 * sizeof(uintptr_t)); hp->rrp.tried[n] |= m; return NGX_OK; } static void * ngx_http_upstream_hash_create_conf(ngx_conf_t *cf) { ngx_http_upstream_hash_srv_conf_t *conf; conf = ngx_palloc(cf->pool, sizeof(ngx_http_upstream_hash_srv_conf_t)); if (conf == NULL) { return NULL; } conf->points = NULL; return conf; } static char * ngx_http_upstream_hash(ngx_conf_t *cf, ngx_command_t *cmd, void *conf) { ngx_http_upstream_hash_srv_conf_t *hcf = conf; ngx_str_t *value; ngx_http_upstream_srv_conf_t *uscf; ngx_http_compile_complex_value_t ccv; value = cf->args->elts; ngx_memzero(&ccv, sizeof(ngx_http_compile_complex_value_t)); ccv.cf = cf; ccv.value = &value[1]; ccv.complex_value = &hcf->key; if (ngx_http_compile_complex_value(&ccv) != NGX_OK) { return NGX_CONF_ERROR; } uscf = ngx_http_conf_get_module_srv_conf(cf, ngx_http_upstream_module); if (uscf->peer.init_upstream) { ngx_conf_log_error(NGX_LOG_WARN, cf, 0, "load balancing method redefined"); } uscf->flags = NGX_HTTP_UPSTREAM_CREATE |NGX_HTTP_UPSTREAM_WEIGHT |NGX_HTTP_UPSTREAM_MAX_CONNS |NGX_HTTP_UPSTREAM_MAX_FAILS |NGX_HTTP_UPSTREAM_FAIL_TIMEOUT |NGX_HTTP_UPSTREAM_DOWN; if (cf->args->nelts == 2) { uscf->peer.init_upstream = ngx_http_upstream_init_hash; } else if (ngx_strcmp(value[2].data, "consistent") == 0) { uscf->peer.init_upstream = ngx_http_upstream_init_chash; } else { ngx_conf_log_error(NGX_LOG_EMERG, cf, 0, "invalid parameter \"%V\"", &value[2]); return NGX_CONF_ERROR; } return NGX_CONF_OK; }