view src/os/win32/ngx_atomic.h @ 6949:ff0c8e11edbc

Simplified and improved sendfile() code on Linux. The ngx_linux_sendfile() function is now used for both normal sendfile() and sendfile in threads. The ngx_linux_sendfile_thread() function was modified to use the same interface as ngx_linux_sendfile(), and is simply called from ngx_linux_sendfile() when threads are enabled. Special return code NGX_DONE is used to indicate that a thread task was posted and no further actions are needed. If number of bytes sent is less that what we were sending, we now always retry sending. This is needed for sendfile() in threads as the number of bytes we are sending might have been changed since the thread task was posted. And this is also needed for Linux 4.3+, as sendfile() might be interrupted at any time and provides no indication if it was interrupted or not (ticket #1174).
author Maxim Dounin <mdounin@mdounin.ru>
date Tue, 28 Mar 2017 18:15:39 +0300
parents 2cd019520210
children
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/*
 * Copyright (C) Igor Sysoev
 * Copyright (C) Nginx, Inc.
 */


#ifndef _NGX_ATOMIC_H_INCLUDED_
#define _NGX_ATOMIC_H_INCLUDED_


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


#define NGX_HAVE_ATOMIC_OPS   1

typedef int32_t                     ngx_atomic_int_t;
typedef uint32_t                    ngx_atomic_uint_t;
typedef volatile ngx_atomic_uint_t  ngx_atomic_t;
#define NGX_ATOMIC_T_LEN            (sizeof("-2147483648") - 1)


#if defined( __WATCOMC__ ) || defined( __BORLANDC__ ) || defined(__GNUC__)    \
    || ( _MSC_VER >= 1300 )

/* the new SDK headers */

#define ngx_atomic_cmp_set(lock, old, set)                                    \
    ((ngx_atomic_uint_t) InterlockedCompareExchange((long *) lock, set, old)  \
                         == old)

#else

/* the old MS VC6.0SP2 SDK headers */

#define ngx_atomic_cmp_set(lock, old, set)                                    \
    (InterlockedCompareExchange((void **) lock, (void *) set, (void *) old)   \
     == (void *) old)

#endif


#define ngx_atomic_fetch_add(p, add) InterlockedExchangeAdd((long *) p, add)


#define ngx_memory_barrier()


#if defined( __BORLANDC__ ) || ( __WATCOMC__ < 1230 )

/*
 * Borland C++ 5.5 (tasm32) and Open Watcom C prior to 1.3
 * do not understand the "pause" instruction
 */

#define ngx_cpu_pause()
#else
#define ngx_cpu_pause()       __asm { pause }
#endif


void ngx_spinlock(ngx_atomic_t *lock, ngx_atomic_int_t value, ngx_uint_t spin);

#define ngx_trylock(lock)  (*(lock) == 0 && ngx_atomic_cmp_set(lock, 0, 1))
#define ngx_unlock(lock)    *(lock) = 0


#endif /* _NGX_ATOMIC_H_INCLUDED_ */