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view src/os/unix/ngx_atomic.h @ 7668:0a04e5e4c40b

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Large block sizes on Linux are now ignored (ticket #1168). NFS on Linux is known to report wsize as a block size (in both f_bsize and f_frsize, both in statfs() and statvfs()). On the other hand, typical file system block sizes on Linux (ext2/ext3/ext4, XFS) are limited to pagesize. (With FAT, block sizes can be at least up to 512k in extreme cases, but this doesn't really matter, see below.) To avoid too aggressive cache clearing on NFS volumes on Linux, block sizes larger than pagesize are now ignored. Note that it is safe to ignore large block sizes. Since 3899:e7cd13b7f759 (1.0.1) cache size is calculated based on fstat() st_blocks, and rounding to file system block size is preserved mostly for Windows. Note well that on other OSes valid block sizes seen are at least up to 65536. In particular, UFS on FreeBSD is known to work well with block and fragment sizes set to 65536.
author Maxim Dounin <mdounin@mdounin.ru>
date Mon, 22 Jun 2020 18:02:58 +0300
parents 2cd019520210
children 09d15a2dbc6b
line wrap: on
line source


/*
 * 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>


#if (NGX_HAVE_LIBATOMIC)

#define AO_REQUIRE_CAS
#include <atomic_ops.h>

#define NGX_HAVE_ATOMIC_OPS  1

typedef long                        ngx_atomic_int_t;
typedef AO_t                        ngx_atomic_uint_t;
typedef volatile ngx_atomic_uint_t  ngx_atomic_t;

#if (NGX_PTR_SIZE == 8)
#define NGX_ATOMIC_T_LEN            (sizeof("-9223372036854775808") - 1)
#else
#define NGX_ATOMIC_T_LEN            (sizeof("-2147483648") - 1)
#endif

#define ngx_atomic_cmp_set(lock, old, new)                                    \
    AO_compare_and_swap(lock, old, new)
#define ngx_atomic_fetch_add(value, add)                                      \
    AO_fetch_and_add(value, add)
#define ngx_memory_barrier()        AO_nop()
#define ngx_cpu_pause()


#elif (NGX_DARWIN_ATOMIC)

/*
 * use Darwin 8 atomic(3) and barrier(3) operations
 * optimized at run-time for UP and SMP
 */

#include <libkern/OSAtomic.h>

/* "bool" conflicts with perl's CORE/handy.h */
#if 0
#undef bool
#endif


#define NGX_HAVE_ATOMIC_OPS  1

#if (NGX_PTR_SIZE == 8)

typedef int64_t                     ngx_atomic_int_t;
typedef uint64_t                    ngx_atomic_uint_t;
#define NGX_ATOMIC_T_LEN            (sizeof("-9223372036854775808") - 1)

#define ngx_atomic_cmp_set(lock, old, new)                                    \
    OSAtomicCompareAndSwap64Barrier(old, new, (int64_t *) lock)

#define ngx_atomic_fetch_add(value, add)                                      \
    (OSAtomicAdd64(add, (int64_t *) value) - add)

#else

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

#define ngx_atomic_cmp_set(lock, old, new)                                    \
    OSAtomicCompareAndSwap32Barrier(old, new, (int32_t *) lock)

#define ngx_atomic_fetch_add(value, add)                                      \
    (OSAtomicAdd32(add, (int32_t *) value) - add)

#endif

#define ngx_memory_barrier()        OSMemoryBarrier()

#define ngx_cpu_pause()

typedef volatile ngx_atomic_uint_t  ngx_atomic_t;


#elif (NGX_HAVE_GCC_ATOMIC)

/* GCC 4.1 builtin atomic operations */

#define NGX_HAVE_ATOMIC_OPS  1

typedef long                        ngx_atomic_int_t;
typedef unsigned long               ngx_atomic_uint_t;

#if (NGX_PTR_SIZE == 8)
#define NGX_ATOMIC_T_LEN            (sizeof("-9223372036854775808") - 1)
#else
#define NGX_ATOMIC_T_LEN            (sizeof("-2147483648") - 1)
#endif

typedef volatile ngx_atomic_uint_t  ngx_atomic_t;


#define ngx_atomic_cmp_set(lock, old, set)                                    \
    __sync_bool_compare_and_swap(lock, old, set)

#define ngx_atomic_fetch_add(value, add)                                      \
    __sync_fetch_and_add(value, add)

#define ngx_memory_barrier()        __sync_synchronize()

#if ( __i386__ || __i386 || __amd64__ || __amd64 )
#define ngx_cpu_pause()             __asm__ ("pause")
#else
#define ngx_cpu_pause()
#endif


#elif ( __i386__ || __i386 )

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 ( __SUNPRO_C )

#define NGX_HAVE_ATOMIC_OPS  1

ngx_atomic_uint_t
ngx_atomic_cmp_set(ngx_atomic_t *lock, ngx_atomic_uint_t old,
    ngx_atomic_uint_t set);

ngx_atomic_int_t
ngx_atomic_fetch_add(ngx_atomic_t *value, ngx_atomic_int_t add);

/*
 * Sun Studio 12 exits with segmentation fault on '__asm ("pause")',
 * so ngx_cpu_pause is declared in src/os/unix/ngx_sunpro_x86.il
 */

void
ngx_cpu_pause(void);

/* the code in src/os/unix/ngx_sunpro_x86.il */

#define ngx_memory_barrier()        __asm (".volatile"); __asm (".nonvolatile")


#else /* ( __GNUC__ || __INTEL_COMPILER ) */

#define NGX_HAVE_ATOMIC_OPS  1

#include "ngx_gcc_atomic_x86.h"

#endif


#elif ( __amd64__ || __amd64 )

typedef int64_t                     ngx_atomic_int_t;
typedef uint64_t                    ngx_atomic_uint_t;
typedef volatile ngx_atomic_uint_t  ngx_atomic_t;
#define NGX_ATOMIC_T_LEN            (sizeof("-9223372036854775808") - 1)


#if ( __SUNPRO_C )

#define NGX_HAVE_ATOMIC_OPS  1

ngx_atomic_uint_t
ngx_atomic_cmp_set(ngx_atomic_t *lock, ngx_atomic_uint_t old,
    ngx_atomic_uint_t set);

ngx_atomic_int_t
ngx_atomic_fetch_add(ngx_atomic_t *value, ngx_atomic_int_t add);

/*
 * Sun Studio 12 exits with segmentation fault on '__asm ("pause")',
 * so ngx_cpu_pause is declared in src/os/unix/ngx_sunpro_amd64.il
 */

void
ngx_cpu_pause(void);

/* the code in src/os/unix/ngx_sunpro_amd64.il */

#define ngx_memory_barrier()        __asm (".volatile"); __asm (".nonvolatile")


#else /* ( __GNUC__ || __INTEL_COMPILER ) */

#define NGX_HAVE_ATOMIC_OPS  1

#include "ngx_gcc_atomic_amd64.h"

#endif


#elif ( __sparc__ || __sparc || __sparcv9 )

#if (NGX_PTR_SIZE == 8)

typedef int64_t                     ngx_atomic_int_t;
typedef uint64_t                    ngx_atomic_uint_t;
#define NGX_ATOMIC_T_LEN            (sizeof("-9223372036854775808") - 1)

#else

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

#endif

typedef volatile ngx_atomic_uint_t  ngx_atomic_t;


#if ( __SUNPRO_C )

#define NGX_HAVE_ATOMIC_OPS  1

#include "ngx_sunpro_atomic_sparc64.h"


#else /* ( __GNUC__ || __INTEL_COMPILER ) */

#define NGX_HAVE_ATOMIC_OPS  1

#include "ngx_gcc_atomic_sparc64.h"

#endif


#elif ( __powerpc__ || __POWERPC__ )

#define NGX_HAVE_ATOMIC_OPS  1

#if (NGX_PTR_SIZE == 8)

typedef int64_t                     ngx_atomic_int_t;
typedef uint64_t                    ngx_atomic_uint_t;
#define NGX_ATOMIC_T_LEN            (sizeof("-9223372036854775808") - 1)

#else

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

#endif

typedef volatile ngx_atomic_uint_t  ngx_atomic_t;


#include "ngx_gcc_atomic_ppc.h"

#endif


#if !(NGX_HAVE_ATOMIC_OPS)

#define NGX_HAVE_ATOMIC_OPS  0

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)


static ngx_inline ngx_atomic_uint_t
ngx_atomic_cmp_set(ngx_atomic_t *lock, ngx_atomic_uint_t old,
    ngx_atomic_uint_t set)
{
    if (*lock == old) {
        *lock = set;
        return 1;
    }

    return 0;
}


static ngx_inline ngx_atomic_int_t
ngx_atomic_fetch_add(ngx_atomic_t *value, ngx_atomic_int_t add)
{
    ngx_atomic_int_t  old;

    old = *value;
    *value += add;

    return old;
}

#define ngx_memory_barrier()
#define ngx_cpu_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_ */