Mercurial > hg > nginx
view src/core/ngx_palloc.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 | ef935cd7ed8d |
children |
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/* * Copyright (C) Igor Sysoev * Copyright (C) Nginx, Inc. */ #ifndef _NGX_PALLOC_H_INCLUDED_ #define _NGX_PALLOC_H_INCLUDED_ #include <ngx_config.h> #include <ngx_core.h> /* * NGX_MAX_ALLOC_FROM_POOL should be (ngx_pagesize - 1), i.e. 4095 on x86. * On Windows NT it decreases a number of locked pages in a kernel. */ #define NGX_MAX_ALLOC_FROM_POOL (ngx_pagesize - 1) #define NGX_DEFAULT_POOL_SIZE (16 * 1024) #define NGX_POOL_ALIGNMENT 16 #define NGX_MIN_POOL_SIZE \ ngx_align((sizeof(ngx_pool_t) + 2 * sizeof(ngx_pool_large_t)), \ NGX_POOL_ALIGNMENT) typedef void (*ngx_pool_cleanup_pt)(void *data); typedef struct ngx_pool_cleanup_s ngx_pool_cleanup_t; struct ngx_pool_cleanup_s { ngx_pool_cleanup_pt handler; void *data; ngx_pool_cleanup_t *next; }; typedef struct ngx_pool_large_s ngx_pool_large_t; struct ngx_pool_large_s { ngx_pool_large_t *next; void *alloc; }; typedef struct { u_char *last; u_char *end; ngx_pool_t *next; ngx_uint_t failed; } ngx_pool_data_t; struct ngx_pool_s { ngx_pool_data_t d; size_t max; ngx_pool_t *current; ngx_chain_t *chain; ngx_pool_large_t *large; ngx_pool_cleanup_t *cleanup; ngx_log_t *log; }; typedef struct { ngx_fd_t fd; u_char *name; ngx_log_t *log; } ngx_pool_cleanup_file_t; ngx_pool_t *ngx_create_pool(size_t size, ngx_log_t *log); void ngx_destroy_pool(ngx_pool_t *pool); void ngx_reset_pool(ngx_pool_t *pool); void *ngx_palloc(ngx_pool_t *pool, size_t size); void *ngx_pnalloc(ngx_pool_t *pool, size_t size); void *ngx_pcalloc(ngx_pool_t *pool, size_t size); void *ngx_pmemalign(ngx_pool_t *pool, size_t size, size_t alignment); ngx_int_t ngx_pfree(ngx_pool_t *pool, void *p); ngx_pool_cleanup_t *ngx_pool_cleanup_add(ngx_pool_t *p, size_t size); void ngx_pool_run_cleanup_file(ngx_pool_t *p, ngx_fd_t fd); void ngx_pool_cleanup_file(void *data); void ngx_pool_delete_file(void *data); #endif /* _NGX_PALLOC_H_INCLUDED_ */