diff options
Diffstat (limited to 'app/nginx/src/core/ngx_spinlock.c')
-rw-r--r-- | app/nginx/src/core/ngx_spinlock.c | 53 |
1 files changed, 53 insertions, 0 deletions
diff --git a/app/nginx/src/core/ngx_spinlock.c b/app/nginx/src/core/ngx_spinlock.c new file mode 100644 index 0000000..9c93afa --- /dev/null +++ b/app/nginx/src/core/ngx_spinlock.c @@ -0,0 +1,53 @@ + +/* + * Copyright (C) Igor Sysoev + * Copyright (C) Nginx, Inc. + */ + + +#include <ngx_config.h> +#include <ngx_core.h> + + +void +ngx_spinlock(ngx_atomic_t *lock, ngx_atomic_int_t value, ngx_uint_t spin) +{ + +#if (NGX_HAVE_ATOMIC_OPS) + + ngx_uint_t i, n; + + for ( ;; ) { + + if (*lock == 0 && ngx_atomic_cmp_set(lock, 0, value)) { + return; + } + + if (ngx_ncpu > 1) { + + for (n = 1; n < spin; n <<= 1) { + + for (i = 0; i < n; i++) { + ngx_cpu_pause(); + } + + if (*lock == 0 && ngx_atomic_cmp_set(lock, 0, value)) { + return; + } + } + } + + ngx_sched_yield(); + } + +#else + +#if (NGX_THREADS) + +#error ngx_spinlock() or ngx_atomic_cmp_set() are not defined ! + +#endif + +#endif + +} |