Mercurial > hg > nginx-quic
view src/os/unix/ngx_alloc.h @ 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 | d620f497c50f |
children |
line wrap: on
line source
/* * Copyright (C) Igor Sysoev * Copyright (C) Nginx, Inc. */ #ifndef _NGX_ALLOC_H_INCLUDED_ #define _NGX_ALLOC_H_INCLUDED_ #include <ngx_config.h> #include <ngx_core.h> void *ngx_alloc(size_t size, ngx_log_t *log); void *ngx_calloc(size_t size, ngx_log_t *log); #define ngx_free free /* * Linux has memalign() or posix_memalign() * Solaris has memalign() * FreeBSD 7.0 has posix_memalign(), besides, early version's malloc() * aligns allocations bigger than page size at the page boundary */ #if (NGX_HAVE_POSIX_MEMALIGN || NGX_HAVE_MEMALIGN) void *ngx_memalign(size_t alignment, size_t size, ngx_log_t *log); #else #define ngx_memalign(alignment, size, log) ngx_alloc(size, log) #endif extern ngx_uint_t ngx_pagesize; extern ngx_uint_t ngx_pagesize_shift; extern ngx_uint_t ngx_cacheline_size; #endif /* _NGX_ALLOC_H_INCLUDED_ */