Mercurial > hg > nginx
view src/os/unix/ngx_gcc_atomic_amd64.h @ 9202:e88cdaa0f1ff
AIO operations now add timers (ticket #2162).
Each AIO (thread IO) operation being run is now accompanied with 1-minute
timer. This timer prevents unexpected shutdown of the worker process while
an AIO operation is running, and logs an alert if the operation is running
for too long.
This fixes "open socket left" alerts during worker processes shutdown
due to pending AIO (or thread IO) operations while corresponding requests
have no timers. In particular, such errors were observed while reading
cache headers (ticket #2162), and with worker_shutdown_timeout.
author | Maxim Dounin <mdounin@mdounin.ru> |
---|---|
date | Mon, 29 Jan 2024 10:31:37 +0300 |
parents | d620f497c50f |
children |
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/* * Copyright (C) Igor Sysoev * Copyright (C) Nginx, Inc. */ #if (NGX_SMP) #define NGX_SMP_LOCK "lock;" #else #define NGX_SMP_LOCK #endif /* * "cmpxchgq r, [m]": * * if (rax == [m]) { * zf = 1; * [m] = r; * } else { * zf = 0; * rax = [m]; * } * * * The "r" is any register, %rax (%r0) - %r16. * The "=a" and "a" are the %rax register. * Although we can return result in any register, we use "a" because it is * used in cmpxchgq anyway. The result is actually in %al but not in $rax, * however as the code is inlined gcc can test %al as well as %rax. * * The "cc" means that flags were changed. */ static ngx_inline ngx_atomic_uint_t ngx_atomic_cmp_set(ngx_atomic_t *lock, ngx_atomic_uint_t old, ngx_atomic_uint_t set) { u_char res; __asm__ volatile ( NGX_SMP_LOCK " cmpxchgq %3, %1; " " sete %0; " : "=a" (res) : "m" (*lock), "a" (old), "r" (set) : "cc", "memory"); return res; } /* * "xaddq r, [m]": * * temp = [m]; * [m] += r; * r = temp; * * * The "+r" is any register, %rax (%r0) - %r16. * The "cc" means that flags were changed. */ static ngx_inline ngx_atomic_int_t ngx_atomic_fetch_add(ngx_atomic_t *value, ngx_atomic_int_t add) { __asm__ volatile ( NGX_SMP_LOCK " xaddq %0, %1; " : "+r" (add) : "m" (*value) : "cc", "memory"); return add; } #define ngx_memory_barrier() __asm__ volatile ("" ::: "memory") #define ngx_cpu_pause() __asm__ ("pause")