view src/os/unix/ngx_thread_id.c @ 6422:768e287a6f36

Fixed sendfile in threads (or with aio preload) and subrequests. If sendfile in threads is used, it is possible that multiple subrequests will trigger multiple ngx_linux_sendfile_thread() calls, as operations are only serialized in output chain based on r->aio, that is, on subrequest level. This resulted in "task #N already active" alerts, in particular, when running proxy_store.t with "aio threads; sendfile on;". Fix is to tolerate duplicate calls, with an additional safety check that the file is the same as previously used. The same problem also affects "aio on; sendfile on;" on FreeBSD (previously known as "aio sendfile;"), where aio->preload_handler() could be called multiple times due to similar reasons, resulting in "second aio post" alerts. Fix is the same as well. It is also believed that similar problems can arise if a filter calls the next body filter multiple times for some reason. These are mostly theoretical though.
author Maxim Dounin <mdounin@mdounin.ru>
date Thu, 03 Mar 2016 21:14:12 +0300
parents 466bd63b63d1
children
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/*
 * Copyright (C) Igor Sysoev
 * Copyright (C) Nginx, Inc.
 */


#include <ngx_config.h>
#include <ngx_core.h>
#include <ngx_thread_pool.h>


#if (NGX_LINUX)

/*
 * Linux thread id is a pid of thread created by clone(2),
 * glibc does not provide a wrapper for gettid().
 */

ngx_tid_t
ngx_thread_tid(void)
{
    return syscall(SYS_gettid);
}

#elif (NGX_FREEBSD) && (__FreeBSD_version >= 900031)

#include <pthread_np.h>

ngx_tid_t
ngx_thread_tid(void)
{
    return pthread_getthreadid_np();
}

#elif (NGX_DARWIN)

/*
 * MacOSX thread has two thread ids:
 *
 * 1) MacOSX 10.6 (Snow Leoprad) has pthread_threadid_np() returning
 *    an uint64_t value, which is obtained using the __thread_selfid()
 *    syscall.  It is a number above 300,000.
 */

ngx_tid_t
ngx_thread_tid(void)
{
    uint64_t  tid;

    (void) pthread_threadid_np(NULL, &tid);
    return tid;
}

/*
 * 2) Kernel thread mach_port_t returned by pthread_mach_thread_np().
 *    It is a number in range 100-100,000.
 *
 * return pthread_mach_thread_np(pthread_self());
 */

#else

ngx_tid_t
ngx_thread_tid(void)
{
    return (uint64_t) (uintptr_t) pthread_self();
}

#endif