Events: available bytes calculation via ioctl(FIONREAD). This makes it possible to avoid looping for a long time while working with a fast enough peer when data are added to the socket buffer faster than we are able to read and process them (ticket #1431). This is basically what we already do on FreeBSD with kqueue, where information about the number of bytes in the socket buffer is returned by the kevent() call. With other event methods rev->available is now set to -1 when the socket is ready for reading. Later in ngx_recv() and ngx_recv_chain(), if full buffer is received, real number of bytes in the socket buffer is retrieved using ioctl(FIONREAD). Reading more than this number of bytes ensures that even with edge-triggered event methods the event will be triggered again, so it is safe to stop processing of the socket and switch to other connections. Using ioctl(FIONREAD) only after reading a full buffer is an optimization. With this approach we only call ioctl(FIONREAD) when there are at least two recv()/readv() calls.

/*
 * Copyright (C) Igor Sysoev
 * Copyright (C) Nginx, Inc.
 */


#ifndef _NGX_PROCESS_CYCLE_H_INCLUDED_
#define _NGX_PROCESS_CYCLE_H_INCLUDED_


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


#define NGX_PROCESS_SINGLE     0
#define NGX_PROCESS_MASTER     1
#define NGX_PROCESS_SIGNALLER  2
#define NGX_PROCESS_WORKER     3


void ngx_master_process_cycle(ngx_cycle_t *cycle);
void ngx_single_process_cycle(ngx_cycle_t *cycle);
void ngx_close_handle(HANDLE h);


extern ngx_uint_t      ngx_process;
extern ngx_uint_t      ngx_worker;
extern ngx_pid_t       ngx_pid;
extern ngx_uint_t      ngx_exiting;

extern sig_atomic_t    ngx_quit;
extern sig_atomic_t    ngx_terminate;
extern sig_atomic_t    ngx_reopen;

extern ngx_uint_t      ngx_inherited;
extern ngx_pid_t       ngx_new_binary;


extern HANDLE          ngx_master_process_event;
extern char            ngx_master_process_event_name[];


#endif /* _NGX_PROCESS_CYCLE_H_INCLUDED_ */