Mercurial > hg > nginx
view src/core/ngx_shmtx.c @ 4436:311b358658c8 stable-1.0
Merge of r4339, r4340, r4341:
Cache fixes:
*) Obsolete code removed.
The ngx_http_cache() and ngx_http_no_cache_set_slot() functions
were replaced in 0.8.46 and no longer used since then.
*) Handling of cache files with long headers.
There are two possible situations which can lead to this: response
was cached with bigger proxy_buffer_size value (and nginx was
restared since then, i.e. shared memory zone content was lost), or
due to the race in the cache update code (see [1]) we've end up
with fcn->body_start from a different response stored in shared
memory zone.
*) Only complain on long locked entries.
There have been multiple reports of cases where a real locked entry
was removed, resulting in a segmentation fault later in a worker
which locked the entry. It looks like default inactive timeout isn't
enough in real life.
For now just ignore such locked entries, and move them to the top of
the inactive queue to allow processing of other entries.
[1] http://mailman.nginx.org/pipermail/nginx-devel/2011-September/001287.html
author | Maxim Dounin <mdounin@mdounin.ru> |
---|---|
date | Sun, 05 Feb 2012 13:34:08 +0000 |
parents | 0daede16d68b |
children | 3f6040cd731e 4919fb357a5d |
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/* * Copyright (C) Igor Sysoev */ #include <ngx_config.h> #include <ngx_core.h> #if (NGX_HAVE_ATOMIC_OPS) ngx_int_t ngx_shmtx_create(ngx_shmtx_t *mtx, void *addr, u_char *name) { mtx->lock = addr; if (mtx->spin == (ngx_uint_t) -1) { return NGX_OK; } mtx->spin = 2048; #if (NGX_HAVE_POSIX_SEM) if (sem_init(&mtx->sem, 1, 0) == -1) { ngx_log_error(NGX_LOG_ALERT, ngx_cycle->log, ngx_errno, "sem_init() failed"); } else { mtx->semaphore = 1; } #endif return NGX_OK; } void ngx_shmtx_destory(ngx_shmtx_t *mtx) { #if (NGX_HAVE_POSIX_SEM) if (mtx->semaphore) { if (sem_destroy(&mtx->sem) == -1) { ngx_log_error(NGX_LOG_ALERT, ngx_cycle->log, ngx_errno, "sem_destroy() failed"); } } #endif } ngx_uint_t ngx_shmtx_trylock(ngx_shmtx_t *mtx) { ngx_atomic_uint_t val; val = *mtx->lock; return ((val & 0x80000000) == 0 && ngx_atomic_cmp_set(mtx->lock, val, val | 0x80000000)); } void ngx_shmtx_lock(ngx_shmtx_t *mtx) { ngx_uint_t i, n; ngx_atomic_uint_t val; ngx_log_debug0(NGX_LOG_DEBUG_CORE, ngx_cycle->log, 0, "shmtx lock"); for ( ;; ) { val = *mtx->lock; if ((val & 0x80000000) == 0 && ngx_atomic_cmp_set(mtx->lock, val, val | 0x80000000)) { return; } if (ngx_ncpu > 1) { for (n = 1; n < mtx->spin; n <<= 1) { for (i = 0; i < n; i++) { ngx_cpu_pause(); } val = *mtx->lock; if ((val & 0x80000000) == 0 && ngx_atomic_cmp_set(mtx->lock, val, val | 0x80000000)) { return; } } } #if (NGX_HAVE_POSIX_SEM) if (mtx->semaphore) { val = *mtx->lock; if ((val & 0x80000000) && ngx_atomic_cmp_set(mtx->lock, val, val + 1)) { ngx_log_debug1(NGX_LOG_DEBUG_CORE, ngx_cycle->log, 0, "shmtx wait %XA", val); while (sem_wait(&mtx->sem) == -1) { ngx_err_t err; err = ngx_errno; if (err != NGX_EINTR) { ngx_log_error(NGX_LOG_ALERT, ngx_cycle->log, err, "sem_wait() failed while waiting on shmtx"); break; } } ngx_log_debug0(NGX_LOG_DEBUG_CORE, ngx_cycle->log, 0, "shmtx awoke"); } continue; } #endif ngx_sched_yield(); } } void ngx_shmtx_unlock(ngx_shmtx_t *mtx) { ngx_atomic_uint_t val, old, wait; if (mtx->spin != (ngx_uint_t) -1) { ngx_log_debug0(NGX_LOG_DEBUG_CORE, ngx_cycle->log, 0, "shmtx unlock"); } for ( ;; ) { old = *mtx->lock; wait = old & 0x7fffffff; val = wait ? wait - 1 : 0; if (ngx_atomic_cmp_set(mtx->lock, old, val)) { break; } } #if (NGX_HAVE_POSIX_SEM) if (wait == 0 || !mtx->semaphore) { return; } ngx_log_debug1(NGX_LOG_DEBUG_CORE, ngx_cycle->log, 0, "shmtx wake %XA", old); if (sem_post(&mtx->sem) == -1) { ngx_log_error(NGX_LOG_ALERT, ngx_cycle->log, ngx_errno, "sem_post() failed while wake shmtx"); } #endif } #else ngx_int_t ngx_shmtx_create(ngx_shmtx_t *mtx, void *addr, u_char *name) { if (mtx->name) { if (ngx_strcmp(name, mtx->name) == 0) { mtx->name = name; return NGX_OK; } ngx_shmtx_destory(mtx); } mtx->fd = ngx_open_file(name, NGX_FILE_RDWR, NGX_FILE_CREATE_OR_OPEN, NGX_FILE_DEFAULT_ACCESS); if (mtx->fd == NGX_INVALID_FILE) { ngx_log_error(NGX_LOG_EMERG, ngx_cycle->log, ngx_errno, ngx_open_file_n " \"%s\" failed", name); return NGX_ERROR; } if (ngx_delete_file(name) == NGX_FILE_ERROR) { ngx_log_error(NGX_LOG_ALERT, ngx_cycle->log, ngx_errno, ngx_delete_file_n " \"%s\" failed", name); } mtx->name = name; return NGX_OK; } void ngx_shmtx_destory(ngx_shmtx_t *mtx) { if (ngx_close_file(mtx->fd) == NGX_FILE_ERROR) { ngx_log_error(NGX_LOG_ALERT, ngx_cycle->log, ngx_errno, ngx_close_file_n " \"%s\" failed", mtx->name); } } ngx_uint_t ngx_shmtx_trylock(ngx_shmtx_t *mtx) { ngx_err_t err; err = ngx_trylock_fd(mtx->fd); if (err == 0) { return 1; } if (err == NGX_EAGAIN) { return 0; } #if __osf__ /* Tru64 UNIX */ if (err == NGX_EACCESS) { return 0; } #endif ngx_log_abort(err, ngx_trylock_fd_n " %s failed", mtx->name); return 0; } void ngx_shmtx_lock(ngx_shmtx_t *mtx) { ngx_err_t err; err = ngx_lock_fd(mtx->fd); if (err == 0) { return; } ngx_log_abort(err, ngx_lock_fd_n " %s failed", mtx->name); } void ngx_shmtx_unlock(ngx_shmtx_t *mtx) { ngx_err_t err; err = ngx_unlock_fd(mtx->fd); if (err == 0) { return; } ngx_log_abort(err, ngx_unlock_fd_n " %s failed", mtx->name); } #endif