Mercurial > hg > nginx
changeset 6101:682d8222c6b1
Core: read/write locks.
| author | Ruslan Ermilov <ru@nginx.com> |
|---|---|
| date | Sat, 21 Mar 2015 14:05:08 +0300 |
| parents | c44459611d91 |
| children | 3264b7828f72 |
| files | auto/sources src/core/ngx_core.h src/core/ngx_rwlock.c src/core/ngx_rwlock.h |
| diffstat | 4 files changed, 136 insertions(+), 0 deletions(-) [+] |
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--- a/auto/sources +++ b/auto/sources @@ -28,6 +28,7 @@ CORE_DEPS="src/core/nginx.h \ src/core/ngx_sha1.h \ src/core/ngx_rbtree.h \ src/core/ngx_radix_tree.h \ + src/core/ngx_rwlock.h \ src/core/ngx_slab.h \ src/core/ngx_times.h \ src/core/ngx_shmtx.h \ @@ -65,6 +66,7 @@ CORE_SRCS="src/core/nginx.c \ src/core/ngx_connection.c \ src/core/ngx_cycle.c \ src/core/ngx_spinlock.c \ + src/core/ngx_rwlock.c \ src/core/ngx_cpuinfo.c \ src/core/ngx_conf_file.c \ src/core/ngx_resolver.c \
--- a/src/core/ngx_core.h +++ b/src/core/ngx_core.h @@ -68,6 +68,7 @@ typedef void (*ngx_connection_handler_pt #endif #include <ngx_radix_tree.h> #include <ngx_times.h> +#include <ngx_rwlock.h> #include <ngx_shmtx.h> #include <ngx_slab.h> #include <ngx_inet.h>
new file mode 100644 --- /dev/null +++ b/src/core/ngx_rwlock.c @@ -0,0 +1,112 @@ + +/* + * Copyright (C) Ruslan Ermilov + * Copyright (C) Nginx, Inc. + */ + + +#include <ngx_config.h> +#include <ngx_core.h> + + +#if (NGX_HAVE_ATOMIC_OPS) + + +#define NGX_RWLOCK_SPIN 2048 +#define NGX_RWLOCK_WLOCK ((ngx_atomic_uint_t) -1) + + +void +ngx_rwlock_wlock(ngx_atomic_t *lock) +{ + ngx_uint_t i, n; + + for ( ;; ) { + + if (*lock == 0 && ngx_atomic_cmp_set(lock, 0, NGX_RWLOCK_WLOCK)) { + return; + } + + if (ngx_ncpu > 1) { + + for (n = 1; n < NGX_RWLOCK_SPIN; n <<= 1) { + + for (i = 0; i < n; i++) { + ngx_cpu_pause(); + } + + if (*lock == 0 + && ngx_atomic_cmp_set(lock, 0, NGX_RWLOCK_WLOCK)) + { + return; + } + } + } + + ngx_sched_yield(); + } +} + + +void +ngx_rwlock_rlock(ngx_atomic_t *lock) +{ + ngx_uint_t i, n; + ngx_atomic_uint_t readers; + + for ( ;; ) { + readers = *lock; + + if (readers != NGX_RWLOCK_WLOCK + && ngx_atomic_cmp_set(lock, readers, readers + 1)) + { + return; + } + + if (ngx_ncpu > 1) { + + for (n = 1; n < NGX_RWLOCK_SPIN; n <<= 1) { + + for (i = 0; i < n; i++) { + ngx_cpu_pause(); + } + + readers = *lock; + + if (readers != NGX_RWLOCK_WLOCK + && ngx_atomic_cmp_set(lock, readers, readers + 1)) + { + return; + } + } + } + + ngx_sched_yield(); + } +} + + +void +ngx_rwlock_unlock(ngx_atomic_t *lock) +{ + ngx_atomic_uint_t readers; + + readers = *lock; + + if (readers == NGX_RWLOCK_WLOCK) { + *lock = 0; + return; + } + + for ( ;; ) { + + if (ngx_atomic_cmp_set(lock, readers, readers - 1)) { + return; + } + + readers = *lock; + } +} + + +#endif
new file mode 100644 --- /dev/null +++ b/src/core/ngx_rwlock.h @@ -0,0 +1,21 @@ + +/* + * Copyright (C) Ruslan Ermilov + * Copyright (C) Nginx, Inc. + */ + + +#ifndef _NGX_RWLOCK_H_INCLUDED_ +#define _NGX_RWLOCK_H_INCLUDED_ + + +#include <ngx_config.h> +#include <ngx_core.h> + + +void ngx_rwlock_wlock(ngx_atomic_t *lock); +void ngx_rwlock_rlock(ngx_atomic_t *lock); +void ngx_rwlock_unlock(ngx_atomic_t *lock); + + +#endif /* _NGX_RWLOCK_H_INCLUDED_ */