view src/core/ngx_queue.h @ 5569:462ae7eedc68 stable-1.4

Fixed TCP_DEFER_ACCEPT handling (ticket #353). Backed out 05a56ebb084a, as it turns out that kernel can return connections without any delay if syncookies are used. This basically means we can't assume anything about connections returned with deferred accept set. To solve original problem the 05a56ebb084a tried to solve, i.e. to don't wait longer than needed if a connection was accepted after deferred accept timeout, this patch changes a timeout set with setsockopt(TCP_DEFER_ACCEPT) to 1 second, unconditionally. This is believed to be enough for speed improvements, and doesn't imply major changes to timeouts used. Note that before 2.6.32 connections were dropped after a timeout. Though it is believed that 1s is still appropriate for kernels before 2.6.32, as previously tcp_synack_retries controlled the actual timeout and 1s results in more than 1 minute actual timeout by default.
author Maxim Dounin <mdounin@mdounin.ru>
date Tue, 28 Jan 2014 15:40:46 +0400
parents d620f497c50f
children 3038bd4d7816
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/*
 * Copyright (C) Igor Sysoev
 * Copyright (C) Nginx, Inc.
 */


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


#ifndef _NGX_QUEUE_H_INCLUDED_
#define _NGX_QUEUE_H_INCLUDED_


typedef struct ngx_queue_s  ngx_queue_t;

struct ngx_queue_s {
    ngx_queue_t  *prev;
    ngx_queue_t  *next;
};


#define ngx_queue_init(q)                                                     \
    (q)->prev = q;                                                            \
    (q)->next = q


#define ngx_queue_empty(h)                                                    \
    (h == (h)->prev)


#define ngx_queue_insert_head(h, x)                                           \
    (x)->next = (h)->next;                                                    \
    (x)->next->prev = x;                                                      \
    (x)->prev = h;                                                            \
    (h)->next = x


#define ngx_queue_insert_after   ngx_queue_insert_head


#define ngx_queue_insert_tail(h, x)                                           \
    (x)->prev = (h)->prev;                                                    \
    (x)->prev->next = x;                                                      \
    (x)->next = h;                                                            \
    (h)->prev = x


#define ngx_queue_head(h)                                                     \
    (h)->next


#define ngx_queue_last(h)                                                     \
    (h)->prev


#define ngx_queue_sentinel(h)                                                 \
    (h)


#define ngx_queue_next(q)                                                     \
    (q)->next


#define ngx_queue_prev(q)                                                     \
    (q)->prev


#if (NGX_DEBUG)

#define ngx_queue_remove(x)                                                   \
    (x)->next->prev = (x)->prev;                                              \
    (x)->prev->next = (x)->next;                                              \
    (x)->prev = NULL;                                                         \
    (x)->next = NULL

#else

#define ngx_queue_remove(x)                                                   \
    (x)->next->prev = (x)->prev;                                              \
    (x)->prev->next = (x)->next

#endif


#define ngx_queue_split(h, q, n)                                              \
    (n)->prev = (h)->prev;                                                    \
    (n)->prev->next = n;                                                      \
    (n)->next = q;                                                            \
    (h)->prev = (q)->prev;                                                    \
    (h)->prev->next = h;                                                      \
    (q)->prev = n;


#define ngx_queue_add(h, n)                                                   \
    (h)->prev->next = (n)->next;                                              \
    (n)->next->prev = (h)->prev;                                              \
    (h)->prev = (n)->prev;                                                    \
    (h)->prev->next = h;


#define ngx_queue_data(q, type, link)                                         \
    (type *) ((u_char *) q - offsetof(type, link))


ngx_queue_t *ngx_queue_middle(ngx_queue_t *queue);
void ngx_queue_sort(ngx_queue_t *queue,
    ngx_int_t (*cmp)(const ngx_queue_t *, const ngx_queue_t *));


#endif /* _NGX_QUEUE_H_INCLUDED_ */