view src/core/ngx_list.h @ 8078:5244d3b165ff

SSL: single allocation in session cache on 32-bit platforms. Given the present typical SSL session sizes, on 32-bit platforms it is now beneficial to store all data in a single allocation, since rbtree node + session id + ASN1 representation of a session takes 256 bytes of shared memory (36 + 32 + 150 = about 218 bytes plus SNI server name). Storing all data in a single allocation is beneficial for SNI names up to about 40 characters long and makes it possible to store about 4000 sessions in one megabyte (instead of about 3000 sessions now). This also slightly simplifies the code.
author Maxim Dounin <mdounin@mdounin.ru>
date Wed, 12 Oct 2022 20:14:40 +0300
parents d620f497c50f
children
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/*
 * Copyright (C) Igor Sysoev
 * Copyright (C) Nginx, Inc.
 */


#ifndef _NGX_LIST_H_INCLUDED_
#define _NGX_LIST_H_INCLUDED_


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


typedef struct ngx_list_part_s  ngx_list_part_t;

struct ngx_list_part_s {
    void             *elts;
    ngx_uint_t        nelts;
    ngx_list_part_t  *next;
};


typedef struct {
    ngx_list_part_t  *last;
    ngx_list_part_t   part;
    size_t            size;
    ngx_uint_t        nalloc;
    ngx_pool_t       *pool;
} ngx_list_t;


ngx_list_t *ngx_list_create(ngx_pool_t *pool, ngx_uint_t n, size_t size);

static ngx_inline ngx_int_t
ngx_list_init(ngx_list_t *list, ngx_pool_t *pool, ngx_uint_t n, size_t size)
{
    list->part.elts = ngx_palloc(pool, n * size);
    if (list->part.elts == NULL) {
        return NGX_ERROR;
    }

    list->part.nelts = 0;
    list->part.next = NULL;
    list->last = &list->part;
    list->size = size;
    list->nalloc = n;
    list->pool = pool;

    return NGX_OK;
}


/*
 *
 *  the iteration through the list:
 *
 *  part = &list.part;
 *  data = part->elts;
 *
 *  for (i = 0 ;; i++) {
 *
 *      if (i >= part->nelts) {
 *          if (part->next == NULL) {
 *              break;
 *          }
 *
 *          part = part->next;
 *          data = part->elts;
 *          i = 0;
 *      }
 *
 *      ...  data[i] ...
 *
 *  }
 */


void *ngx_list_push(ngx_list_t *list);


#endif /* _NGX_LIST_H_INCLUDED_ */