Mercurial > hg > nginx-quic
view src/os/win32/ngx_atomic.h @ 4010:74a93d3fdd85
Fixing cpu hog with all upstream servers marked "down".
The following configuration causes nginx to hog cpu due to infinite loop
in ngx_http_upstream_get_peer():
upstream backend {
server 127.0.0.1:8080 down;
server 127.0.0.1:8080 down;
}
server {
...
location / {
proxy_pass http://backend;
}
}
Make sure we don't loop infinitely in ngx_http_upstream_get_peer() but stop
after resetting peer weights once.
Return 0 if we are stuck. This is guaranteed to work as peer 0 always exists,
and eventually ngx_http_upstream_get_round_robin_peer() will do the right
thing falling back to backup servers or returning NGX_BUSY.
| author | Maxim Dounin <mdounin@mdounin.ru> |
|---|---|
| date | Thu, 18 Aug 2011 16:52:38 +0000 |
| parents | 7658e9c7e814 |
| children | d620f497c50f |
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/* * Copyright (C) Igor Sysoev */ #ifndef _NGX_ATOMIC_H_INCLUDED_ #define _NGX_ATOMIC_H_INCLUDED_ #include <ngx_config.h> #include <ngx_core.h> #define NGX_HAVE_ATOMIC_OPS 1 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 defined( __WATCOMC__ ) || defined( __BORLANDC__ ) || ( _MSC_VER >= 1300 ) /* the new SDK headers */ #define ngx_atomic_cmp_set(lock, old, set) \ ((ngx_atomic_uint_t) InterlockedCompareExchange((long *) lock, set, old) \ == old) #else /* the old MS VC6.0SP2 SDK headers */ #define ngx_atomic_cmp_set(lock, old, set) \ (InterlockedCompareExchange((void **) lock, (void *) set, (void *) old) \ == (void *) old) #endif #define ngx_atomic_fetch_add(p, add) InterlockedExchangeAdd((long *) p, add) #define ngx_memory_barrier() #if defined( __BORLANDC__ ) || ( __WATCOMC__ < 1230 ) /* * Borland C++ 5.5 (tasm32) and Open Watcom C prior to 1.3 * do not understand the "pause" instruction */ #define ngx_cpu_pause() #else #define ngx_cpu_pause() __asm { 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_ */