Mercurial > hg > nginx
view src/http/ngx_http_upstream_round_robin.h @ 7969:84c60a3cd12a stable-1.20
Changed ngx_chain_update_chains() to test tag first (ticket #2248).
Without this change, aio used with HTTP/2 can result in connection hang,
as observed with "aio threads; aio_write on;" and proxying (ticket #2248).
The problem is that HTTP/2 updates buffers outside of the output filters
(notably, marks them as sent), and then posts a write event to call
output filters. If a filter does not call the next one for some reason
(for example, because of an AIO operation in progress), this might
result in a state when the owner of a buffer already called
ngx_chain_update_chains() and can reuse the buffer, while the same buffer
is still sitting in the busy chain of some other filter.
In the particular case a buffer was sitting in output chain's ctx->busy,
and was reused by event pipe. Output chain's ctx->busy was permanently
blocked by it, and this resulted in connection hang.
Fix is to change ngx_chain_update_chains() to skip buffers from other
modules unconditionally, without trying to wait for these buffers to
become empty.
author | Maxim Dounin <mdounin@mdounin.ru> |
---|---|
date | Sat, 30 Oct 2021 02:39:19 +0300 |
parents | 90cc7194e993 |
children |
line wrap: on
line source
/* * Copyright (C) Igor Sysoev * Copyright (C) Nginx, Inc. */ #ifndef _NGX_HTTP_UPSTREAM_ROUND_ROBIN_H_INCLUDED_ #define _NGX_HTTP_UPSTREAM_ROUND_ROBIN_H_INCLUDED_ #include <ngx_config.h> #include <ngx_core.h> #include <ngx_http.h> typedef struct ngx_http_upstream_rr_peer_s ngx_http_upstream_rr_peer_t; struct ngx_http_upstream_rr_peer_s { struct sockaddr *sockaddr; socklen_t socklen; ngx_str_t name; ngx_str_t server; ngx_int_t current_weight; ngx_int_t effective_weight; ngx_int_t weight; ngx_uint_t conns; ngx_uint_t max_conns; ngx_uint_t fails; time_t accessed; time_t checked; ngx_uint_t max_fails; time_t fail_timeout; ngx_msec_t slow_start; ngx_msec_t start_time; ngx_uint_t down; #if (NGX_HTTP_SSL || NGX_COMPAT) void *ssl_session; int ssl_session_len; #endif #if (NGX_HTTP_UPSTREAM_ZONE) ngx_atomic_t lock; #endif ngx_http_upstream_rr_peer_t *next; NGX_COMPAT_BEGIN(32) NGX_COMPAT_END }; typedef struct ngx_http_upstream_rr_peers_s ngx_http_upstream_rr_peers_t; struct ngx_http_upstream_rr_peers_s { ngx_uint_t number; #if (NGX_HTTP_UPSTREAM_ZONE) ngx_slab_pool_t *shpool; ngx_atomic_t rwlock; ngx_http_upstream_rr_peers_t *zone_next; #endif ngx_uint_t total_weight; ngx_uint_t tries; unsigned single:1; unsigned weighted:1; ngx_str_t *name; ngx_http_upstream_rr_peers_t *next; ngx_http_upstream_rr_peer_t *peer; }; #if (NGX_HTTP_UPSTREAM_ZONE) #define ngx_http_upstream_rr_peers_rlock(peers) \ \ if (peers->shpool) { \ ngx_rwlock_rlock(&peers->rwlock); \ } #define ngx_http_upstream_rr_peers_wlock(peers) \ \ if (peers->shpool) { \ ngx_rwlock_wlock(&peers->rwlock); \ } #define ngx_http_upstream_rr_peers_unlock(peers) \ \ if (peers->shpool) { \ ngx_rwlock_unlock(&peers->rwlock); \ } #define ngx_http_upstream_rr_peer_lock(peers, peer) \ \ if (peers->shpool) { \ ngx_rwlock_wlock(&peer->lock); \ } #define ngx_http_upstream_rr_peer_unlock(peers, peer) \ \ if (peers->shpool) { \ ngx_rwlock_unlock(&peer->lock); \ } #else #define ngx_http_upstream_rr_peers_rlock(peers) #define ngx_http_upstream_rr_peers_wlock(peers) #define ngx_http_upstream_rr_peers_unlock(peers) #define ngx_http_upstream_rr_peer_lock(peers, peer) #define ngx_http_upstream_rr_peer_unlock(peers, peer) #endif typedef struct { ngx_uint_t config; ngx_http_upstream_rr_peers_t *peers; ngx_http_upstream_rr_peer_t *current; uintptr_t *tried; uintptr_t data; } ngx_http_upstream_rr_peer_data_t; ngx_int_t ngx_http_upstream_init_round_robin(ngx_conf_t *cf, ngx_http_upstream_srv_conf_t *us); ngx_int_t ngx_http_upstream_init_round_robin_peer(ngx_http_request_t *r, ngx_http_upstream_srv_conf_t *us); ngx_int_t ngx_http_upstream_create_round_robin_peer(ngx_http_request_t *r, ngx_http_upstream_resolved_t *ur); ngx_int_t ngx_http_upstream_get_round_robin_peer(ngx_peer_connection_t *pc, void *data); void ngx_http_upstream_free_round_robin_peer(ngx_peer_connection_t *pc, void *data, ngx_uint_t state); #if (NGX_HTTP_SSL) ngx_int_t ngx_http_upstream_set_round_robin_peer_session(ngx_peer_connection_t *pc, void *data); void ngx_http_upstream_save_round_robin_peer_session(ngx_peer_connection_t *pc, void *data); #endif #endif /* _NGX_HTTP_UPSTREAM_ROUND_ROBIN_H_INCLUDED_ */