Mercurial > hg > nginx
view src/core/ngx_thread_pool.c @ 7281:bd6563e81cea
Limit req: improved handling of negative times.
Negative times can appear since workers only update time on an event
loop iteration start. If a worker was blocked for a long time during
an event loop iteration, it is possible that another worker already
updated the time stored in the node. As such, time since last update
of the node (ms) will be negative.
Previous code used ngx_abs(ms) in the calculations. That is, negative
times were effectively treated as positive ones. As a result, it was
not possible to maintain high request rates, where the same node can be
updated multiple times from during an event loop iteration.
In particular, this affected setups with many SSL handshakes, see
http://mailman.nginx.org/pipermail/nginx/2018-May/056291.html.
Fix is to only update the last update time stored in the node if the
new time is larger than previously stored one. If a future time is
stored in the node, we preserve this time as is.
To prevent breaking things on platforms without monotonic time available
if system time is updated backwards, a safety limit of 60 seconds is
used. If the time stored in the node is more than 60 seconds in the future,
we assume that the time was changed backwards and update lr->last
to the current time.
author | Maxim Dounin <mdounin@mdounin.ru> |
---|---|
date | Wed, 30 May 2018 15:40:34 +0300 |
parents | 33d075b9097d |
children |
line wrap: on
line source
/* * Copyright (C) Nginx, Inc. * Copyright (C) Valentin V. Bartenev * Copyright (C) Ruslan Ermilov */ #include <ngx_config.h> #include <ngx_core.h> #include <ngx_thread_pool.h> typedef struct { ngx_array_t pools; } ngx_thread_pool_conf_t; typedef struct { ngx_thread_task_t *first; ngx_thread_task_t **last; } ngx_thread_pool_queue_t; #define ngx_thread_pool_queue_init(q) \ (q)->first = NULL; \ (q)->last = &(q)->first struct ngx_thread_pool_s { ngx_thread_mutex_t mtx; ngx_thread_pool_queue_t queue; ngx_int_t waiting; ngx_thread_cond_t cond; ngx_log_t *log; ngx_str_t name; ngx_uint_t threads; ngx_int_t max_queue; u_char *file; ngx_uint_t line; }; static ngx_int_t ngx_thread_pool_init(ngx_thread_pool_t *tp, ngx_log_t *log, ngx_pool_t *pool); static void ngx_thread_pool_destroy(ngx_thread_pool_t *tp); static void ngx_thread_pool_exit_handler(void *data, ngx_log_t *log); static void *ngx_thread_pool_cycle(void *data); static void ngx_thread_pool_handler(ngx_event_t *ev); static char *ngx_thread_pool(ngx_conf_t *cf, ngx_command_t *cmd, void *conf); static void *ngx_thread_pool_create_conf(ngx_cycle_t *cycle); static char *ngx_thread_pool_init_conf(ngx_cycle_t *cycle, void *conf); static ngx_int_t ngx_thread_pool_init_worker(ngx_cycle_t *cycle); static void ngx_thread_pool_exit_worker(ngx_cycle_t *cycle); static ngx_command_t ngx_thread_pool_commands[] = { { ngx_string("thread_pool"), NGX_MAIN_CONF|NGX_DIRECT_CONF|NGX_CONF_TAKE23, ngx_thread_pool, 0, 0, NULL }, ngx_null_command }; static ngx_core_module_t ngx_thread_pool_module_ctx = { ngx_string("thread_pool"), ngx_thread_pool_create_conf, ngx_thread_pool_init_conf }; ngx_module_t ngx_thread_pool_module = { NGX_MODULE_V1, &ngx_thread_pool_module_ctx, /* module context */ ngx_thread_pool_commands, /* module directives */ NGX_CORE_MODULE, /* module type */ NULL, /* init master */ NULL, /* init module */ ngx_thread_pool_init_worker, /* init process */ NULL, /* init thread */ NULL, /* exit thread */ ngx_thread_pool_exit_worker, /* exit process */ NULL, /* exit master */ NGX_MODULE_V1_PADDING }; static ngx_str_t ngx_thread_pool_default = ngx_string("default"); static ngx_uint_t ngx_thread_pool_task_id; static ngx_atomic_t ngx_thread_pool_done_lock; static ngx_thread_pool_queue_t ngx_thread_pool_done; static ngx_int_t ngx_thread_pool_init(ngx_thread_pool_t *tp, ngx_log_t *log, ngx_pool_t *pool) { int err; pthread_t tid; ngx_uint_t n; pthread_attr_t attr; if (ngx_notify == NULL) { ngx_log_error(NGX_LOG_ALERT, log, 0, "the configured event method cannot be used with thread pools"); return NGX_ERROR; } ngx_thread_pool_queue_init(&tp->queue); if (ngx_thread_mutex_create(&tp->mtx, log) != NGX_OK) { return NGX_ERROR; } if (ngx_thread_cond_create(&tp->cond, log) != NGX_OK) { (void) ngx_thread_mutex_destroy(&tp->mtx, log); return NGX_ERROR; } tp->log = log; err = pthread_attr_init(&attr); if (err) { ngx_log_error(NGX_LOG_ALERT, log, err, "pthread_attr_init() failed"); return NGX_ERROR; } err = pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED); if (err) { ngx_log_error(NGX_LOG_ALERT, log, err, "pthread_attr_setdetachstate() failed"); return NGX_ERROR; } #if 0 err = pthread_attr_setstacksize(&attr, PTHREAD_STACK_MIN); if (err) { ngx_log_error(NGX_LOG_ALERT, log, err, "pthread_attr_setstacksize() failed"); return NGX_ERROR; } #endif for (n = 0; n < tp->threads; n++) { err = pthread_create(&tid, &attr, ngx_thread_pool_cycle, tp); if (err) { ngx_log_error(NGX_LOG_ALERT, log, err, "pthread_create() failed"); return NGX_ERROR; } } (void) pthread_attr_destroy(&attr); return NGX_OK; } static void ngx_thread_pool_destroy(ngx_thread_pool_t *tp) { ngx_uint_t n; ngx_thread_task_t task; volatile ngx_uint_t lock; ngx_memzero(&task, sizeof(ngx_thread_task_t)); task.handler = ngx_thread_pool_exit_handler; task.ctx = (void *) &lock; for (n = 0; n < tp->threads; n++) { lock = 1; if (ngx_thread_task_post(tp, &task) != NGX_OK) { return; } while (lock) { ngx_sched_yield(); } task.event.active = 0; } (void) ngx_thread_cond_destroy(&tp->cond, tp->log); (void) ngx_thread_mutex_destroy(&tp->mtx, tp->log); } static void ngx_thread_pool_exit_handler(void *data, ngx_log_t *log) { ngx_uint_t *lock = data; *lock = 0; pthread_exit(0); } ngx_thread_task_t * ngx_thread_task_alloc(ngx_pool_t *pool, size_t size) { ngx_thread_task_t *task; task = ngx_pcalloc(pool, sizeof(ngx_thread_task_t) + size); if (task == NULL) { return NULL; } task->ctx = task + 1; return task; } ngx_int_t ngx_thread_task_post(ngx_thread_pool_t *tp, ngx_thread_task_t *task) { if (task->event.active) { ngx_log_error(NGX_LOG_ALERT, tp->log, 0, "task #%ui already active", task->id); return NGX_ERROR; } if (ngx_thread_mutex_lock(&tp->mtx, tp->log) != NGX_OK) { return NGX_ERROR; } if (tp->waiting >= tp->max_queue) { (void) ngx_thread_mutex_unlock(&tp->mtx, tp->log); ngx_log_error(NGX_LOG_ERR, tp->log, 0, "thread pool \"%V\" queue overflow: %i tasks waiting", &tp->name, tp->waiting); return NGX_ERROR; } task->event.active = 1; task->id = ngx_thread_pool_task_id++; task->next = NULL; if (ngx_thread_cond_signal(&tp->cond, tp->log) != NGX_OK) { (void) ngx_thread_mutex_unlock(&tp->mtx, tp->log); return NGX_ERROR; } *tp->queue.last = task; tp->queue.last = &task->next; tp->waiting++; (void) ngx_thread_mutex_unlock(&tp->mtx, tp->log); ngx_log_debug2(NGX_LOG_DEBUG_CORE, tp->log, 0, "task #%ui added to thread pool \"%V\"", task->id, &tp->name); return NGX_OK; } static void * ngx_thread_pool_cycle(void *data) { ngx_thread_pool_t *tp = data; int err; sigset_t set; ngx_thread_task_t *task; #if 0 ngx_time_update(); #endif ngx_log_debug1(NGX_LOG_DEBUG_CORE, tp->log, 0, "thread in pool \"%V\" started", &tp->name); sigfillset(&set); sigdelset(&set, SIGILL); sigdelset(&set, SIGFPE); sigdelset(&set, SIGSEGV); sigdelset(&set, SIGBUS); err = pthread_sigmask(SIG_BLOCK, &set, NULL); if (err) { ngx_log_error(NGX_LOG_ALERT, tp->log, err, "pthread_sigmask() failed"); return NULL; } for ( ;; ) { if (ngx_thread_mutex_lock(&tp->mtx, tp->log) != NGX_OK) { return NULL; } /* the number may become negative */ tp->waiting--; while (tp->queue.first == NULL) { if (ngx_thread_cond_wait(&tp->cond, &tp->mtx, tp->log) != NGX_OK) { (void) ngx_thread_mutex_unlock(&tp->mtx, tp->log); return NULL; } } task = tp->queue.first; tp->queue.first = task->next; if (tp->queue.first == NULL) { tp->queue.last = &tp->queue.first; } if (ngx_thread_mutex_unlock(&tp->mtx, tp->log) != NGX_OK) { return NULL; } #if 0 ngx_time_update(); #endif ngx_log_debug2(NGX_LOG_DEBUG_CORE, tp->log, 0, "run task #%ui in thread pool \"%V\"", task->id, &tp->name); task->handler(task->ctx, tp->log); ngx_log_debug2(NGX_LOG_DEBUG_CORE, tp->log, 0, "complete task #%ui in thread pool \"%V\"", task->id, &tp->name); task->next = NULL; ngx_spinlock(&ngx_thread_pool_done_lock, 1, 2048); *ngx_thread_pool_done.last = task; ngx_thread_pool_done.last = &task->next; ngx_memory_barrier(); ngx_unlock(&ngx_thread_pool_done_lock); (void) ngx_notify(ngx_thread_pool_handler); } } static void ngx_thread_pool_handler(ngx_event_t *ev) { ngx_event_t *event; ngx_thread_task_t *task; ngx_log_debug0(NGX_LOG_DEBUG_CORE, ev->log, 0, "thread pool handler"); ngx_spinlock(&ngx_thread_pool_done_lock, 1, 2048); task = ngx_thread_pool_done.first; ngx_thread_pool_done.first = NULL; ngx_thread_pool_done.last = &ngx_thread_pool_done.first; ngx_memory_barrier(); ngx_unlock(&ngx_thread_pool_done_lock); while (task) { ngx_log_debug1(NGX_LOG_DEBUG_CORE, ev->log, 0, "run completion handler for task #%ui", task->id); event = &task->event; task = task->next; event->complete = 1; event->active = 0; event->handler(event); } } static void * ngx_thread_pool_create_conf(ngx_cycle_t *cycle) { ngx_thread_pool_conf_t *tcf; tcf = ngx_pcalloc(cycle->pool, sizeof(ngx_thread_pool_conf_t)); if (tcf == NULL) { return NULL; } if (ngx_array_init(&tcf->pools, cycle->pool, 4, sizeof(ngx_thread_pool_t *)) != NGX_OK) { return NULL; } return tcf; } static char * ngx_thread_pool_init_conf(ngx_cycle_t *cycle, void *conf) { ngx_thread_pool_conf_t *tcf = conf; ngx_uint_t i; ngx_thread_pool_t **tpp; tpp = tcf->pools.elts; for (i = 0; i < tcf->pools.nelts; i++) { if (tpp[i]->threads) { continue; } if (tpp[i]->name.len == ngx_thread_pool_default.len && ngx_strncmp(tpp[i]->name.data, ngx_thread_pool_default.data, ngx_thread_pool_default.len) == 0) { tpp[i]->threads = 32; tpp[i]->max_queue = 65536; continue; } ngx_log_error(NGX_LOG_EMERG, cycle->log, 0, "unknown thread pool \"%V\" in %s:%ui", &tpp[i]->name, tpp[i]->file, tpp[i]->line); return NGX_CONF_ERROR; } return NGX_CONF_OK; } static char * ngx_thread_pool(ngx_conf_t *cf, ngx_command_t *cmd, void *conf) { ngx_str_t *value; ngx_uint_t i; ngx_thread_pool_t *tp; value = cf->args->elts; tp = ngx_thread_pool_add(cf, &value[1]); if (tp == NULL) { return NGX_CONF_ERROR; } if (tp->threads) { ngx_conf_log_error(NGX_LOG_EMERG, cf, 0, "duplicate thread pool \"%V\"", &tp->name); return NGX_CONF_ERROR; } tp->max_queue = 65536; for (i = 2; i < cf->args->nelts; i++) { if (ngx_strncmp(value[i].data, "threads=", 8) == 0) { tp->threads = ngx_atoi(value[i].data + 8, value[i].len - 8); if (tp->threads == (ngx_uint_t) NGX_ERROR || tp->threads == 0) { ngx_conf_log_error(NGX_LOG_EMERG, cf, 0, "invalid threads value \"%V\"", &value[i]); return NGX_CONF_ERROR; } continue; } if (ngx_strncmp(value[i].data, "max_queue=", 10) == 0) { tp->max_queue = ngx_atoi(value[i].data + 10, value[i].len - 10); if (tp->max_queue == NGX_ERROR) { ngx_conf_log_error(NGX_LOG_EMERG, cf, 0, "invalid max_queue value \"%V\"", &value[i]); return NGX_CONF_ERROR; } continue; } } if (tp->threads == 0) { ngx_conf_log_error(NGX_LOG_EMERG, cf, 0, "\"%V\" must have \"threads\" parameter", &cmd->name); return NGX_CONF_ERROR; } return NGX_CONF_OK; } ngx_thread_pool_t * ngx_thread_pool_add(ngx_conf_t *cf, ngx_str_t *name) { ngx_thread_pool_t *tp, **tpp; ngx_thread_pool_conf_t *tcf; if (name == NULL) { name = &ngx_thread_pool_default; } tp = ngx_thread_pool_get(cf->cycle, name); if (tp) { return tp; } tp = ngx_pcalloc(cf->pool, sizeof(ngx_thread_pool_t)); if (tp == NULL) { return NULL; } tp->name = *name; tp->file = cf->conf_file->file.name.data; tp->line = cf->conf_file->line; tcf = (ngx_thread_pool_conf_t *) ngx_get_conf(cf->cycle->conf_ctx, ngx_thread_pool_module); tpp = ngx_array_push(&tcf->pools); if (tpp == NULL) { return NULL; } *tpp = tp; return tp; } ngx_thread_pool_t * ngx_thread_pool_get(ngx_cycle_t *cycle, ngx_str_t *name) { ngx_uint_t i; ngx_thread_pool_t **tpp; ngx_thread_pool_conf_t *tcf; tcf = (ngx_thread_pool_conf_t *) ngx_get_conf(cycle->conf_ctx, ngx_thread_pool_module); tpp = tcf->pools.elts; for (i = 0; i < tcf->pools.nelts; i++) { if (tpp[i]->name.len == name->len && ngx_strncmp(tpp[i]->name.data, name->data, name->len) == 0) { return tpp[i]; } } return NULL; } static ngx_int_t ngx_thread_pool_init_worker(ngx_cycle_t *cycle) { ngx_uint_t i; ngx_thread_pool_t **tpp; ngx_thread_pool_conf_t *tcf; if (ngx_process != NGX_PROCESS_WORKER && ngx_process != NGX_PROCESS_SINGLE) { return NGX_OK; } tcf = (ngx_thread_pool_conf_t *) ngx_get_conf(cycle->conf_ctx, ngx_thread_pool_module); if (tcf == NULL) { return NGX_OK; } ngx_thread_pool_queue_init(&ngx_thread_pool_done); tpp = tcf->pools.elts; for (i = 0; i < tcf->pools.nelts; i++) { if (ngx_thread_pool_init(tpp[i], cycle->log, cycle->pool) != NGX_OK) { return NGX_ERROR; } } return NGX_OK; } static void ngx_thread_pool_exit_worker(ngx_cycle_t *cycle) { ngx_uint_t i; ngx_thread_pool_t **tpp; ngx_thread_pool_conf_t *tcf; if (ngx_process != NGX_PROCESS_WORKER && ngx_process != NGX_PROCESS_SINGLE) { return; } tcf = (ngx_thread_pool_conf_t *) ngx_get_conf(cycle->conf_ctx, ngx_thread_pool_module); if (tcf == NULL) { return; } tpp = tcf->pools.elts; for (i = 0; i < tcf->pools.nelts; i++) { ngx_thread_pool_destroy(tpp[i]); } }