Mercurial > hg > nginx-quic
view src/event/modules/ngx_iocp_module.c @ 4207:4fc91bae6f83
Better recheck of dead upstream servers.
Previously nginx used to mark backend again as live as soon as fail_timeout
passes (10s by default) since last failure. On the other hand, detecting
dead backend takes up to 60s (proxy_connect_timeout) in typical situation
"backend is down and doesn't respond to any packets". This resulted in
suboptimal behaviour in the above situation (up to 23% of requests were
directed to dead backend with default settings).
More detailed description of the problem may be found here (in Russian):
http://mailman.nginx.org/pipermail/nginx-ru/2011-August/042172.html
Fix is to only allow one request after fail_timeout passes, and
mark backend as "live" only if this request succeeds.
Note that with new code backend will not be marked "live" unless "check"
request is completed, and this may take a while in some specific workloads
(e.g. streaming). This is believed to be acceptable.
author | Maxim Dounin <mdounin@mdounin.ru> |
---|---|
date | Wed, 12 Oct 2011 14:22:48 +0000 |
parents | ab353d7dc182 |
children | d620f497c50f |
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/* * Copyright (C) Igor Sysoev */ #include <ngx_config.h> #include <ngx_core.h> #include <ngx_event.h> #include <ngx_iocp_module.h> static ngx_int_t ngx_iocp_init(ngx_cycle_t *cycle, ngx_msec_t timer); static ngx_thread_value_t __stdcall ngx_iocp_timer(void *data); static void ngx_iocp_done(ngx_cycle_t *cycle); static ngx_int_t ngx_iocp_add_event(ngx_event_t *ev, ngx_int_t event, ngx_uint_t key); static ngx_int_t ngx_iocp_del_connection(ngx_connection_t *c, ngx_uint_t flags); static ngx_int_t ngx_iocp_process_events(ngx_cycle_t *cycle, ngx_msec_t timer, ngx_uint_t flags); static void *ngx_iocp_create_conf(ngx_cycle_t *cycle); static char *ngx_iocp_init_conf(ngx_cycle_t *cycle, void *conf); static ngx_str_t iocp_name = ngx_string("iocp"); static ngx_command_t ngx_iocp_commands[] = { {ngx_string("iocp_threads"), NGX_EVENT_CONF|NGX_CONF_TAKE1, ngx_conf_set_num_slot, 0, offsetof(ngx_iocp_conf_t, threads), NULL}, {ngx_string("post_acceptex"), NGX_EVENT_CONF|NGX_CONF_TAKE1, ngx_conf_set_num_slot, 0, offsetof(ngx_iocp_conf_t, post_acceptex), NULL}, {ngx_string("acceptex_read"), NGX_EVENT_CONF|NGX_CONF_FLAG, ngx_conf_set_flag_slot, 0, offsetof(ngx_iocp_conf_t, acceptex_read), NULL}, ngx_null_command }; ngx_event_module_t ngx_iocp_module_ctx = { &iocp_name, ngx_iocp_create_conf, /* create configuration */ ngx_iocp_init_conf, /* init configuration */ { ngx_iocp_add_event, /* add an event */ NULL, /* delete an event */ NULL, /* enable an event */ NULL, /* disable an event */ NULL, /* add an connection */ ngx_iocp_del_connection, /* delete an connection */ NULL, /* process the changes */ ngx_iocp_process_events, /* process the events */ ngx_iocp_init, /* init the events */ ngx_iocp_done /* done the events */ } }; ngx_module_t ngx_iocp_module = { NGX_MODULE_V1, &ngx_iocp_module_ctx, /* module context */ ngx_iocp_commands, /* module directives */ NGX_EVENT_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 }; ngx_os_io_t ngx_iocp_io = { ngx_overlapped_wsarecv, NULL, ngx_udp_overlapped_wsarecv, NULL, ngx_overlapped_wsasend_chain, 0 }; static HANDLE iocp; static ngx_tid_t timer_thread; static ngx_msec_t msec; static ngx_int_t ngx_iocp_init(ngx_cycle_t *cycle, ngx_msec_t timer) { ngx_iocp_conf_t *cf; cf = ngx_event_get_conf(cycle->conf_ctx, ngx_iocp_module); if (iocp == NULL) { iocp = CreateIoCompletionPort(INVALID_HANDLE_VALUE, NULL, 0, cf->threads); } if (iocp == NULL) { ngx_log_error(NGX_LOG_ALERT, cycle->log, ngx_errno, "CreateIoCompletionPort() failed"); return NGX_ERROR; } ngx_io = ngx_iocp_io; ngx_event_actions = ngx_iocp_module_ctx.actions; ngx_event_flags = NGX_USE_AIO_EVENT|NGX_USE_IOCP_EVENT; if (timer == 0) { return NGX_OK; } /* * The waitable timer could not be used, because * GetQueuedCompletionStatus() does not set a thread to alertable state */ if (timer_thread == NULL) { msec = timer; if (ngx_create_thread(&timer_thread, ngx_iocp_timer, &msec, cycle->log) != 0) { return NGX_ERROR; } } ngx_event_flags |= NGX_USE_TIMER_EVENT; return NGX_OK; } static ngx_thread_value_t __stdcall ngx_iocp_timer(void *data) { ngx_msec_t timer = *(ngx_msec_t *) data; ngx_log_debug2(NGX_LOG_DEBUG_EVENT, ngx_cycle->log, 0, "THREAD %p %p", &msec, data); for ( ;; ) { Sleep(timer); ngx_time_update(); #if 1 ngx_log_debug0(NGX_LOG_DEBUG_EVENT, ngx_cycle->log, 0, "timer"); #endif } #ifdef __WATCOMC__ return 0; #endif } static void ngx_iocp_done(ngx_cycle_t *cycle) { if (CloseHandle(iocp) == -1) { ngx_log_error(NGX_LOG_ALERT, cycle->log, ngx_errno, "iocp CloseHandle() failed"); } iocp = NULL; } static ngx_int_t ngx_iocp_add_event(ngx_event_t *ev, ngx_int_t event, ngx_uint_t key) { ngx_connection_t *c; c = (ngx_connection_t *) ev->data; c->read->active = 1; c->write->active = 1; ngx_log_debug3(NGX_LOG_DEBUG_EVENT, ev->log, 0, "iocp add: fd:%d k:%ui ov:%p", c->fd, key, &ev->ovlp); if (CreateIoCompletionPort((HANDLE) c->fd, iocp, key, 0) == NULL) { ngx_log_error(NGX_LOG_ALERT, c->log, ngx_errno, "CreateIoCompletionPort() failed"); return NGX_ERROR; } return NGX_OK; } static ngx_int_t ngx_iocp_del_connection(ngx_connection_t *c, ngx_uint_t flags) { #if 0 if (flags & NGX_CLOSE_EVENT) { return NGX_OK; } if (CancelIo((HANDLE) c->fd) == 0) { ngx_log_error(NGX_LOG_ALERT, c->log, ngx_errno, "CancelIo() failed"); return NGX_ERROR; } #endif return NGX_OK; } static ngx_int_t ngx_iocp_process_events(ngx_cycle_t *cycle, ngx_msec_t timer, ngx_uint_t flags) { int rc; u_int key; u_long bytes; ngx_err_t err; ngx_msec_t delta; ngx_event_t *ev; ngx_event_ovlp_t *ovlp; if (timer == NGX_TIMER_INFINITE) { timer = INFINITE; } ngx_log_debug1(NGX_LOG_DEBUG_EVENT, cycle->log, 0, "iocp timer: %M", timer); rc = GetQueuedCompletionStatus(iocp, &bytes, (LPDWORD) &key, (LPOVERLAPPED *) &ovlp, (u_long) timer); if (rc == 0) { err = ngx_errno; } else { err = 0; } delta = ngx_current_msec; if (flags & NGX_UPDATE_TIME) { ngx_time_update(); } ngx_log_debug4(NGX_LOG_DEBUG_EVENT, cycle->log, 0, "iocp: %d b:%d k:%d ov:%p", rc, bytes, key, ovlp); if (timer != INFINITE) { delta = ngx_current_msec - delta; ngx_log_debug2(NGX_LOG_DEBUG_EVENT, cycle->log, 0, "iocp timer: %M, delta: %M", timer, delta); } if (err) { if (ovlp == NULL) { if (err != WAIT_TIMEOUT) { ngx_log_error(NGX_LOG_ALERT, cycle->log, err, "GetQueuedCompletionStatus() failed"); return NGX_ERROR; } return NGX_OK; } ovlp->error = err; } if (ovlp == NULL) { ngx_log_error(NGX_LOG_ALERT, cycle->log, 0, "GetQueuedCompletionStatus() returned no operation"); return NGX_ERROR; } ev = ovlp->event; ngx_log_debug1(NGX_LOG_DEBUG_EVENT, cycle->log, err, "iocp event:%p", ev); if (err == ERROR_NETNAME_DELETED /* the socket was closed */ || err == ERROR_OPERATION_ABORTED /* the operation was canceled */) { /* * the WSA_OPERATION_ABORTED completion notification * for a file descriptor that was closed */ ngx_log_debug1(NGX_LOG_DEBUG_EVENT, cycle->log, err, "iocp: aborted event %p", ev); return NGX_OK; } if (err) { ngx_log_error(NGX_LOG_ALERT, cycle->log, err, "GetQueuedCompletionStatus() returned operation error"); } switch (key) { case NGX_IOCP_ACCEPT: if (bytes) { ev->ready = 1; } break; case NGX_IOCP_IO: ev->complete = 1; ev->ready = 1; break; case NGX_IOCP_CONNECT: ev->ready = 1; } ev->available = bytes; ngx_log_debug1(NGX_LOG_DEBUG_EVENT, cycle->log, 0, "iocp event handler: %p", ev->handler); ev->handler(ev); return NGX_OK; } static void * ngx_iocp_create_conf(ngx_cycle_t *cycle) { ngx_iocp_conf_t *cf; cf = ngx_palloc(cycle->pool, sizeof(ngx_iocp_conf_t)); if (cf == NULL) { return NGX_CONF_ERROR; } cf->threads = NGX_CONF_UNSET; cf->post_acceptex = NGX_CONF_UNSET; cf->acceptex_read = NGX_CONF_UNSET; return cf; } static char * ngx_iocp_init_conf(ngx_cycle_t *cycle, void *conf) { ngx_iocp_conf_t *cf = conf; ngx_conf_init_value(cf->threads, 0); ngx_conf_init_value(cf->post_acceptex, 10); ngx_conf_init_value(cf->acceptex_read, 1); return NGX_CONF_OK; }