Mercurial > hg > nginx
view src/core/ngx_buf.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 | ec2e6893caaa |
children |
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/* * Copyright (C) Igor Sysoev * Copyright (C) Nginx, Inc. */ #ifndef _NGX_BUF_H_INCLUDED_ #define _NGX_BUF_H_INCLUDED_ #include <ngx_config.h> #include <ngx_core.h> typedef void * ngx_buf_tag_t; typedef struct ngx_buf_s ngx_buf_t; struct ngx_buf_s { u_char *pos; u_char *last; off_t file_pos; off_t file_last; u_char *start; /* start of buffer */ u_char *end; /* end of buffer */ ngx_buf_tag_t tag; ngx_file_t *file; ngx_buf_t *shadow; /* the buf's content could be changed */ unsigned temporary:1; /* * the buf's content is in a memory cache or in a read only memory * and must not be changed */ unsigned memory:1; /* the buf's content is mmap()ed and must not be changed */ unsigned mmap:1; unsigned recycled:1; unsigned in_file:1; unsigned flush:1; unsigned sync:1; unsigned last_buf:1; unsigned last_in_chain:1; unsigned last_shadow:1; unsigned temp_file:1; /* STUB */ int num; }; struct ngx_chain_s { ngx_buf_t *buf; ngx_chain_t *next; }; typedef struct { ngx_int_t num; size_t size; } ngx_bufs_t; typedef struct ngx_output_chain_ctx_s ngx_output_chain_ctx_t; typedef ngx_int_t (*ngx_output_chain_filter_pt)(void *ctx, ngx_chain_t *in); typedef void (*ngx_output_chain_aio_pt)(ngx_output_chain_ctx_t *ctx, ngx_file_t *file); struct ngx_output_chain_ctx_s { ngx_buf_t *buf; ngx_chain_t *in; ngx_chain_t *free; ngx_chain_t *busy; unsigned sendfile:1; unsigned directio:1; unsigned unaligned:1; unsigned need_in_memory:1; unsigned need_in_temp:1; unsigned aio:1; #if (NGX_HAVE_FILE_AIO || NGX_COMPAT) ngx_output_chain_aio_pt aio_handler; #endif #if (NGX_THREADS || NGX_COMPAT) ngx_int_t (*thread_handler)(ngx_thread_task_t *task, ngx_file_t *file); ngx_thread_task_t *thread_task; #endif off_t alignment; ngx_pool_t *pool; ngx_int_t allocated; ngx_bufs_t bufs; ngx_buf_tag_t tag; ngx_output_chain_filter_pt output_filter; void *filter_ctx; }; typedef struct { ngx_chain_t *out; ngx_chain_t **last; ngx_connection_t *connection; ngx_pool_t *pool; off_t limit; } ngx_chain_writer_ctx_t; #define NGX_CHAIN_ERROR (ngx_chain_t *) NGX_ERROR #define ngx_buf_in_memory(b) ((b)->temporary || (b)->memory || (b)->mmap) #define ngx_buf_in_memory_only(b) (ngx_buf_in_memory(b) && !(b)->in_file) #define ngx_buf_special(b) \ (((b)->flush || (b)->last_buf || (b)->sync) \ && !ngx_buf_in_memory(b) && !(b)->in_file) #define ngx_buf_sync_only(b) \ ((b)->sync && !ngx_buf_in_memory(b) \ && !(b)->in_file && !(b)->flush && !(b)->last_buf) #define ngx_buf_size(b) \ (ngx_buf_in_memory(b) ? (off_t) ((b)->last - (b)->pos): \ ((b)->file_last - (b)->file_pos)) ngx_buf_t *ngx_create_temp_buf(ngx_pool_t *pool, size_t size); ngx_chain_t *ngx_create_chain_of_bufs(ngx_pool_t *pool, ngx_bufs_t *bufs); #define ngx_alloc_buf(pool) ngx_palloc(pool, sizeof(ngx_buf_t)) #define ngx_calloc_buf(pool) ngx_pcalloc(pool, sizeof(ngx_buf_t)) ngx_chain_t *ngx_alloc_chain_link(ngx_pool_t *pool); #define ngx_free_chain(pool, cl) \ (cl)->next = (pool)->chain; \ (pool)->chain = (cl) ngx_int_t ngx_output_chain(ngx_output_chain_ctx_t *ctx, ngx_chain_t *in); ngx_int_t ngx_chain_writer(void *ctx, ngx_chain_t *in); ngx_int_t ngx_chain_add_copy(ngx_pool_t *pool, ngx_chain_t **chain, ngx_chain_t *in); ngx_chain_t *ngx_chain_get_free_buf(ngx_pool_t *p, ngx_chain_t **free); void ngx_chain_update_chains(ngx_pool_t *p, ngx_chain_t **free, ngx_chain_t **busy, ngx_chain_t **out, ngx_buf_tag_t tag); off_t ngx_chain_coalesce_file(ngx_chain_t **in, off_t limit); ngx_chain_t *ngx_chain_update_sent(ngx_chain_t *in, off_t sent); #endif /* _NGX_BUF_H_INCLUDED_ */