Mercurial > hg > nginx-quic
view src/os/unix/ngx_setaffinity.c @ 5970:74edc0ccf27a
Core: fixed a race resulting in extra sem_post()'s.
The mtx->wait counter was not decremented if we were able to obtain the lock
right after incrementing it. This resulted in unneeded sem_post() calls,
eventually leading to EOVERFLOW errors being logged, "sem_post() failed
while wake shmtx (75: Value too large for defined data type)".
To close the race, mtx->wait is now decremented if we obtain the lock right
after incrementing it in ngx_shmtx_lock(). The result can become -1 if a
concurrent ngx_shmtx_unlock() decrements mtx->wait before the added code does.
However, that only leads to one extra iteration in the next call of
ngx_shmtx_lock().
author | Roman Arutyunyan <arut@nginx.com> |
---|---|
date | Wed, 04 Feb 2015 16:22:43 +0300 |
parents | f31162fefe01 |
children | 7296b38f6416 |
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/* * Copyright (C) Nginx, Inc. */ #include <ngx_config.h> #include <ngx_core.h> #if (NGX_HAVE_CPUSET_SETAFFINITY) #include <sys/cpuset.h> void ngx_setaffinity(uint64_t cpu_affinity, ngx_log_t *log) { cpuset_t mask; ngx_uint_t i; ngx_log_error(NGX_LOG_NOTICE, log, 0, "cpuset_setaffinity(0x%08Xl)", cpu_affinity); CPU_ZERO(&mask); i = 0; do { if (cpu_affinity & 1) { CPU_SET(i, &mask); } i++; cpu_affinity >>= 1; } while (cpu_affinity); if (cpuset_setaffinity(CPU_LEVEL_WHICH, CPU_WHICH_PID, -1, sizeof(cpuset_t), &mask) == -1) { ngx_log_error(NGX_LOG_ALERT, log, ngx_errno, "cpuset_setaffinity() failed"); } } #elif (NGX_HAVE_SCHED_SETAFFINITY) void ngx_setaffinity(uint64_t cpu_affinity, ngx_log_t *log) { cpu_set_t mask; ngx_uint_t i; ngx_log_error(NGX_LOG_NOTICE, log, 0, "sched_setaffinity(0x%08Xl)", cpu_affinity); CPU_ZERO(&mask); i = 0; do { if (cpu_affinity & 1) { CPU_SET(i, &mask); } i++; cpu_affinity >>= 1; } while (cpu_affinity); if (sched_setaffinity(0, sizeof(cpu_set_t), &mask) == -1) { ngx_log_error(NGX_LOG_ALERT, log, ngx_errno, "sched_setaffinity() failed"); } } #endif