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/*****************************************************************************
Copyright (c) 1995, 2016, Oracle and/or its affiliates. All Rights Reserved.
Copyright (c) 2017, 2018, MariaDB Corporation.
This program is free software; you can redistribute it and/or modify it under
the terms of the GNU General Public License as published by the Free Software
Foundation; version 2 of the License.
This program is distributed in the hope that it will be useful, but WITHOUT
ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
You should have received a copy of the GNU General Public License along with
this program; if not, write to the Free Software Foundation, Inc.,
51 Franklin Street, Suite 500, Boston, MA 02110-1335 USA
*****************************************************************************/
/**************************************************//**
@file os/os0thread.cc
The interface to the operating system thread control primitives
Created 9/8/1995 Heikki Tuuri
*******************************************************/
#include "univ.i"
#include "os0thread.h"
#include "srv0srv.h"
/** Number of threads active. */
ulint os_thread_count;
/***************************************************************//**
Compares two thread ids for equality.
@return TRUE if equal */
ibool
os_thread_eq(
/*=========*/
os_thread_id_t a, /*!< in: OS thread or thread id */
os_thread_id_t b) /*!< in: OS thread or thread id */
{
#ifdef _WIN32
if (a == b) {
return(TRUE);
}
return(FALSE);
#else
if (pthread_equal(a, b)) {
return(TRUE);
}
return(FALSE);
#endif
}
/****************************************************************//**
Converts an OS thread id to a ulint. It is NOT guaranteed that the ulint is
unique for the thread though!
@return thread identifier as a number */
ulint
os_thread_pf(
/*=========*/
os_thread_id_t a) /*!< in: OS thread identifier */
{
return((ulint) a);
}
/*****************************************************************//**
Returns the thread identifier of current thread. Currently the thread
identifier in Unix is the thread handle itself. Note that in HP-UX
pthread_t is a struct of 3 fields.
@return current thread identifier */
os_thread_id_t
os_thread_get_curr_id(void)
/*=======================*/
{
#ifdef _WIN32
return(GetCurrentThreadId());
#else
return(pthread_self());
#endif
}
/****************************************************************//**
Creates a new thread of execution. The execution starts from
the function given.
NOTE: We count the number of threads in os_thread_exit(). A created
thread should always use that to exit so thatthe thread count will be
decremented.
We do not return an error code because if there is one, we crash here. */
os_thread_t
os_thread_create_func(
/*==================*/
os_thread_func_t func, /*!< in: pointer to function
from which to start */
void* arg, /*!< in: argument to start
function */
os_thread_id_t* thread_id) /*!< out: id of the created
thread, or NULL */
{
os_thread_id_t new_thread_id;
#ifdef _WIN32
HANDLE handle;
handle = CreateThread(NULL, /* no security attributes */
0, /* default size stack */
func,
arg,
0, /* thread runs immediately */
&new_thread_id);
if (!handle) {
/* If we cannot start a new thread, life has no meaning. */
ib::fatal() << "CreateThread returned " << GetLastError();
}
CloseHandle(handle);
my_atomic_addlint(&os_thread_count, 1);
return((os_thread_t)new_thread_id);
#else /* _WIN32 else */
pthread_attr_t attr;
pthread_attr_init(&attr);
my_atomic_addlint(&os_thread_count, 1);
int ret = pthread_create(&new_thread_id, &attr, func, arg);
ut_a(ret == 0);
pthread_attr_destroy(&attr);
#endif /* not _WIN32 */
ut_a(os_thread_count <= srv_max_n_threads);
/* Return the thread_id if the caller requests it. */
if (thread_id != NULL) {
*thread_id = new_thread_id;
}
return((os_thread_t)new_thread_id);
}
/** Waits until the specified thread completes and joins it.
Its return value is ignored.
@param[in,out] thread thread to join */
void
os_thread_join(
os_thread_id_t thread)
{
#ifdef _WIN32
/* Do nothing. */
#else
#ifdef UNIV_DEBUG
const int ret =
#endif /* UNIV_DEBUG */
pthread_join(thread, NULL);
/* Waiting on already-quit threads is allowed. */
ut_ad(ret == 0 || ret == ESRCH);
#endif /* _WIN32 */
}
/** Exits the current thread.
@param[in] detach if true, the thread will be detached right before
exiting. If false, another thread is responsible for joining this thread */
ATTRIBUTE_NORETURN
void
os_thread_exit(bool detach)
{
#ifdef UNIV_DEBUG_THREAD_CREATION
ib::info() << "Thread exits, id "
<< os_thread_pf(os_thread_get_curr_id());
#endif
#ifdef UNIV_PFS_THREAD
pfs_delete_thread();
#endif
my_atomic_addlint(&os_thread_count, ulint(-1));
#ifdef _WIN32
ExitThread(0);
#else
if (detach) {
pthread_detach(pthread_self());
}
pthread_exit(NULL);
#endif
}
/*****************************************************************//**
Advises the os to give up remainder of the thread's time slice. */
void
os_thread_yield(void)
/*=================*/
{
#if defined(_WIN32)
SwitchToThread();
#else
sched_yield();
#endif
}
/*****************************************************************//**
The thread sleeps at least the time given in microseconds. */
void
os_thread_sleep(
/*============*/
ulint tm) /*!< in: time in microseconds */
{
#ifdef _WIN32
Sleep((DWORD) tm / 1000);
#elif defined(HAVE_NANOSLEEP)
struct timespec t;
t.tv_sec = tm / 1000000;
t.tv_nsec = (tm % 1000000) * 1000;
::nanosleep(&t, NULL);
#else
struct timeval t;
t.tv_sec = tm / 1000000;
t.tv_usec = tm % 1000000;
select(0, NULL, NULL, NULL, &t);
#endif /* _WIN32 */
}
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