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view src/event/ngx_event_timer.h @ 7985:ec2e6893caaa

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Simplified sendfile(SF_NODISKIO) usage. Starting with FreeBSD 11, there is no need to use AIO operations to preload data into cache for sendfile(SF_NODISKIO) to work. Instead, sendfile() handles non-blocking loading data from disk by itself. It still can, however, return EBUSY if a page is already being loaded (for example, by a different process). If this happens, we now post an event for the next event loop iteration, so sendfile() is retried "after a short period", as manpage recommends. The limit of the number of EBUSY tolerated without any progress is preserved, but now it does not result in an alert, since on an idle system event loop iteration might be very short and EBUSY can happen many times in a row. Instead, SF_NODISKIO is simply disabled for one call once the limit is reached. With this change, sendfile(SF_NODISKIO) is now used automatically as long as sendfile() is enabled, and no longer requires "aio on;".
author Maxim Dounin <mdounin@mdounin.ru>
date Mon, 27 Dec 2021 19:48:33 +0300
parents 3069dd358ba2
children
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/*
 * Copyright (C) Igor Sysoev
 * Copyright (C) Nginx, Inc.
 */


#ifndef _NGX_EVENT_TIMER_H_INCLUDED_
#define _NGX_EVENT_TIMER_H_INCLUDED_


#include <ngx_config.h>
#include <ngx_core.h>
#include <ngx_event.h>


#define NGX_TIMER_INFINITE  (ngx_msec_t) -1

#define NGX_TIMER_LAZY_DELAY  300


ngx_int_t ngx_event_timer_init(ngx_log_t *log);
ngx_msec_t ngx_event_find_timer(void);
void ngx_event_expire_timers(void);
ngx_int_t ngx_event_no_timers_left(void);


extern ngx_rbtree_t  ngx_event_timer_rbtree;


static ngx_inline void
ngx_event_del_timer(ngx_event_t *ev)
{
    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);

#if (NGX_DEBUG)
    ev->timer.left = NULL;
    ev->timer.right = NULL;
    ev->timer.parent = NULL;
#endif

    ev->timer_set = 0;
}


static ngx_inline void
ngx_event_add_timer(ngx_event_t *ev, ngx_msec_t timer)
{
    ngx_msec_t      key;
    ngx_msec_int_t  diff;

    key = ngx_current_msec + timer;

    if (ev->timer_set) {

        /*
         * Use a previous timer value if difference between it and a new
         * value is less than NGX_TIMER_LAZY_DELAY milliseconds: this allows
         * to minimize the rbtree operations for fast connections.
         */

        diff = (ngx_msec_int_t) (key - ev->timer.key);

        if (ngx_abs(diff) < NGX_TIMER_LAZY_DELAY) {
            ngx_log_debug3(NGX_LOG_DEBUG_EVENT, ev->log, 0,
                           "event timer: %d, old: %M, new: %M",
                            ngx_event_ident(ev->data), ev->timer.key, key);
            return;
        }

        ngx_del_timer(ev);
    }

    ev->timer.key = key;

    ngx_log_debug3(NGX_LOG_DEBUG_EVENT, ev->log, 0,
                   "event timer add: %d: %M:%M",
                    ngx_event_ident(ev->data), timer, ev->timer.key);

    ngx_rbtree_insert(&ngx_event_timer_rbtree, &ev->timer);

    ev->timer_set = 1;
}


#endif /* _NGX_EVENT_TIMER_H_INCLUDED_ */