Mercurial > hg > nginx-quic
view src/core/ngx_spinlock.c @ 6826:d0404c9a7675
Slab: simplified allocation from slots.
Removed code that would cause an endless loop, and removed condition
check that is always false. The first page in the slot list is
guaranteed to satisfy an allocation.
author | Ruslan Ermilov <ru@nginx.com> |
---|---|
date | Wed, 07 Dec 2016 22:25:37 +0300 |
parents | f737e406aa68 |
children |
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/* * 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 }