Mercurial > hg > nginx
view src/os/unix/ngx_gcc_atomic_amd64.h @ 9299:2706b60dc225 default tip
Core: error logging rate limiting.
With this change, error logging to files can be rate-limited with
the "rate=" parameter. The parameter specifies allowed log messages
rate to a particular file (per worker), in messages per second (m/s).
By default, "rate=1000m/s" is used.
Rate limiting is implemented using the "leaky bucket" method, similarly
to the limit_req module.
Maximum burst size is set to the number of log messages per second
for each severity level, so "error" messages are logged even if the
rate limit is hit by "info" messages (but not vice versa). When the
limit is reached for a particular level, the "too many log messages,
limiting" message is logged at this level.
If debug logging is enabled, either for the particular log file or for
the particular connection, rate limiting is not used.
author | Maxim Dounin <mdounin@mdounin.ru> |
---|---|
date | Tue, 25 Jun 2024 22:58:56 +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")