Mercurial > hg > nginx
view src/event/ngx_event_timer.c @ 4135:d8e24515176e
Fix of cpu hog in event pipe.
If client closed connection in ngx_event_pipe_write_to_downstream(), buffers
in the "out" chain were lost. This caused cpu hog if all available buffers
were in the "out" chain. Fix is to call ngx_chain_update_chains() before
checking return code of output filter to avoid loosing buffers in the "out"
chain.
Note that this situation (all available buffers in the "out" chain) isn't
normal, it should be prevented by busy buffers limit. Though right now it
may happen with complex protocols like fastcgi. This should be addressed
separately.
author | Maxim Dounin <mdounin@mdounin.ru> |
---|---|
date | Tue, 20 Sep 2011 09:55:27 +0000 |
parents | 59b99f217c6d |
children | d620f497c50f |
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/* * Copyright (C) Igor Sysoev */ #include <ngx_config.h> #include <ngx_core.h> #include <ngx_event.h> #if (NGX_THREADS) ngx_mutex_t *ngx_event_timer_mutex; #endif ngx_thread_volatile ngx_rbtree_t ngx_event_timer_rbtree; static ngx_rbtree_node_t ngx_event_timer_sentinel; /* * the event timer rbtree may contain the duplicate keys, however, * it should not be a problem, because we use the rbtree to find * a minimum timer value only */ ngx_int_t ngx_event_timer_init(ngx_log_t *log) { ngx_rbtree_init(&ngx_event_timer_rbtree, &ngx_event_timer_sentinel, ngx_rbtree_insert_timer_value); #if (NGX_THREADS) if (ngx_event_timer_mutex) { ngx_event_timer_mutex->log = log; return NGX_OK; } ngx_event_timer_mutex = ngx_mutex_init(log, 0); if (ngx_event_timer_mutex == NULL) { return NGX_ERROR; } #endif return NGX_OK; } ngx_msec_t ngx_event_find_timer(void) { ngx_msec_int_t timer; ngx_rbtree_node_t *node, *root, *sentinel; if (ngx_event_timer_rbtree.root == &ngx_event_timer_sentinel) { return NGX_TIMER_INFINITE; } ngx_mutex_lock(ngx_event_timer_mutex); root = ngx_event_timer_rbtree.root; sentinel = ngx_event_timer_rbtree.sentinel; node = ngx_rbtree_min(root, sentinel); ngx_mutex_unlock(ngx_event_timer_mutex); timer = (ngx_msec_int_t) node->key - (ngx_msec_int_t) ngx_current_msec; return (ngx_msec_t) (timer > 0 ? timer : 0); } void ngx_event_expire_timers(void) { ngx_event_t *ev; ngx_rbtree_node_t *node, *root, *sentinel; sentinel = ngx_event_timer_rbtree.sentinel; for ( ;; ) { ngx_mutex_lock(ngx_event_timer_mutex); root = ngx_event_timer_rbtree.root; if (root == sentinel) { return; } node = ngx_rbtree_min(root, sentinel); /* node->key <= ngx_current_time */ if ((ngx_msec_int_t) node->key - (ngx_msec_int_t) ngx_current_msec <= 0) { ev = (ngx_event_t *) ((char *) node - offsetof(ngx_event_t, timer)); #if (NGX_THREADS) if (ngx_threaded && ngx_trylock(ev->lock) == 0) { /* * We cannot change the timer of the event that is being * handled by another thread. And we cannot easy walk * the rbtree to find next expired timer so we exit the loop. * However, it should be a rare case when the event that is * being handled has an expired timer. */ ngx_log_debug1(NGX_LOG_DEBUG_EVENT, ev->log, 0, "event %p is busy in expire timers", ev); break; } #endif ngx_log_debug2(NGX_LOG_DEBUG_EVENT, ev->log, 0, "event timer del: %d: %M", ngx_event_ident(ev->data), ev->timer.key); ngx_rbtree_delete(&ngx_event_timer_rbtree, &ev->timer); ngx_mutex_unlock(ngx_event_timer_mutex); #if (NGX_DEBUG) ev->timer.left = NULL; ev->timer.right = NULL; ev->timer.parent = NULL; #endif ev->timer_set = 0; #if (NGX_THREADS) if (ngx_threaded) { ev->posted_timedout = 1; ngx_post_event(ev, &ngx_posted_events); ngx_unlock(ev->lock); continue; } #endif ev->timedout = 1; ev->handler(ev); continue; } break; } ngx_mutex_unlock(ngx_event_timer_mutex); }