Mercurial > hg > nginx
view src/os/win32/ngx_process.h @ 8045:aa28c802409f
Resolver: make TCP write timer event cancelable.
Similar to 70e65bf8dfd7, the change is made to ensure that the ability to
cancel resolver tasks is fully controlled by the caller. As mentioned in the
referenced commit, it is safe to make this timer cancelable because resolve
tasks can have their own timeouts that are not cancelable.
The scenario where this may become a problem is a periodic background resolve
task (not tied to a specific request or a client connection), which receives a
response with short TTL, large enough to warrant fallback to a TCP query.
With each event loop wakeup, we either have a previously set write timer
instance or schedule a new one. The non-cancelable write timer can delay or
block graceful shutdown of a worker even if the ngx_resolver_ctx_t->cancelable
flag is set by the API user, and there are no other tasks or connections.
We use the resolver API in this way to maintain the list of upstream server
addresses specified with the 'resolve' parameter, and there could be third-party
modules implementing similar logic.
author | Aleksei Bavshin <a.bavshin@f5.com> |
---|---|
date | Wed, 01 Jun 2022 20:17:23 -0700 |
parents | 8b84d60ef13d |
children |
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/* * Copyright (C) Igor Sysoev * Copyright (C) Nginx, Inc. */ #ifndef _NGX_PROCESS_H_INCLUDED_ #define _NGX_PROCESS_H_INCLUDED_ typedef DWORD ngx_pid_t; #define NGX_INVALID_PID 0 #define ngx_getpid GetCurrentProcessId #define ngx_getppid() 0 #define ngx_log_pid ngx_pid #define NGX_PROCESS_SYNC_NAME \ (sizeof("ngx_cache_manager_mutex_") + NGX_INT32_LEN) typedef uint64_t ngx_cpuset_t; typedef struct { HANDLE handle; ngx_pid_t pid; char *name; HANDLE term; HANDLE quit; HANDLE reopen; u_char term_event[NGX_PROCESS_SYNC_NAME]; u_char quit_event[NGX_PROCESS_SYNC_NAME]; u_char reopen_event[NGX_PROCESS_SYNC_NAME]; unsigned just_spawn:1; unsigned exiting:1; } ngx_process_t; typedef struct { char *path; char *name; char *args; char *const *argv; char *const *envp; HANDLE child; } ngx_exec_ctx_t; ngx_pid_t ngx_spawn_process(ngx_cycle_t *cycle, char *name, ngx_int_t respawn); ngx_pid_t ngx_execute(ngx_cycle_t *cycle, ngx_exec_ctx_t *ctx); #define ngx_debug_point() #define ngx_sched_yield() SwitchToThread() #define NGX_MAX_PROCESSES (MAXIMUM_WAIT_OBJECTS - 4) #define NGX_PROCESS_RESPAWN -2 #define NGX_PROCESS_JUST_RESPAWN -3 extern int ngx_argc; extern char **ngx_argv; extern char **ngx_os_argv; extern ngx_int_t ngx_last_process; extern ngx_process_t ngx_processes[NGX_MAX_PROCESSES]; extern ngx_pid_t ngx_pid; extern ngx_pid_t ngx_parent; #endif /* _NGX_PROCESS_H_INCLUDED_ */