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freebsd-dev/lib/libthr/thread/thr_gc.c

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- Add libthr but don't hook it up to the regular build yet. This is an adaptation of libc_r for the thr system call interface. This is beta quality code.
2003-04-01 03:46:29 +00:00
/*
* Copyright (c) 1998 John Birrell <jb@cimlogic.com.au>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by John Birrell.
* 4. Neither the name of the author nor the names of any co-contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY JOHN BIRRELL AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $FreeBSD$
*
* Garbage collector thread. Frees memory allocated for dead threads.
*
*/
#include <sys/param.h>
#include <errno.h>
#include <time.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/types.h>
#include <pthread.h>
#include "thr_private.h"
pthread_addr_t
_thread_gc(pthread_addr_t arg)
{
int f_debug;
int f_done = 0;
int ret;
sigset_t mask;
pthread_t pthread;
pthread_t pthread_cln;
struct timespec abstime;
void *p_stack;
/* Block all signals */
sigfillset(&mask);
pthread_sigmask(SIG_BLOCK, &mask, NULL);
/* Mark this thread as a library thread (not a user thread). */
curthread->flags |= PTHREAD_FLAGS_PRIVATE;
/* Set a debug flag based on an environment variable. */
f_debug = (getenv("LIBC_R_DEBUG") != NULL);
/* Set the name of this thread. */
pthread_set_name_np(curthread,"GC");
while (!f_done) {
/* Check if debugging this application. */
if (f_debug)
/* Dump thread info to file. */
_thread_dump_info();
/*
Start locking up the active and dead threads lists. The active threads list is protected by a spinlock_t, but the dead list uses a pthread_mutex because it is necessary to synchronize other threads with the garbage collector thread. Lock/Unlock macros are used so it's easier to make changes to the locks in the future. The 'dead thread list' lock is intended to replace the gc mutex. This doesn't have any practical ramifications. It simply makes it clearer what the purpose of the lock is. The gc will use this lock, instead of the gc mutex, to synchronize access to the dead list with other threads. Modify _pthread_exit() to use these two new locks instead of GIANT_LOCK, and also to properly lock and protect thread state changes, especially with respect to a joining thread. The gc thread was also re-arranged to be more organized and less nested. _pthread_join() was also modified to use the thread list locks. However, locking and unlocking here needs special care because a thread could find itself in a position where it's joining an exiting thread that is waiting on the dead list lock, which this thread (joiner) holds. If the joiner doesn't take care to lock *and* unlock in the same order they (the joiner and the joinee) could deadlock against each other. Approved by: re/blanket libthr
2003-05-25 08:31:33 +00:00
* Lock the list of dead threads which ensures that
- Add libthr but don't hook it up to the regular build yet. This is an adaptation of libc_r for the thr system call interface. This is beta quality code.
2003-04-01 03:46:29 +00:00
* this thread sees another thread exit:
*/
Start locking up the active and dead threads lists. The active threads list is protected by a spinlock_t, but the dead list uses a pthread_mutex because it is necessary to synchronize other threads with the garbage collector thread. Lock/Unlock macros are used so it's easier to make changes to the locks in the future. The 'dead thread list' lock is intended to replace the gc mutex. This doesn't have any practical ramifications. It simply makes it clearer what the purpose of the lock is. The gc will use this lock, instead of the gc mutex, to synchronize access to the dead list with other threads. Modify _pthread_exit() to use these two new locks instead of GIANT_LOCK, and also to properly lock and protect thread state changes, especially with respect to a joining thread. The gc thread was also re-arranged to be more organized and less nested. _pthread_join() was also modified to use the thread list locks. However, locking and unlocking here needs special care because a thread could find itself in a position where it's joining an exiting thread that is waiting on the dead list lock, which this thread (joiner) holds. If the joiner doesn't take care to lock *and* unlock in the same order they (the joiner and the joinee) could deadlock against each other. Approved by: re/blanket libthr
2003-05-25 08:31:33 +00:00
DEAD_LIST_LOCK;
- Add libthr but don't hook it up to the regular build yet. This is an adaptation of libc_r for the thr system call interface. This is beta quality code.
2003-04-01 03:46:29 +00:00
/* No stack or thread structure to free yet. */
p_stack = NULL;
pthread_cln = NULL;
/* Check if this is the last running thread. */
Start locking up the active and dead threads lists. The active threads list is protected by a spinlock_t, but the dead list uses a pthread_mutex because it is necessary to synchronize other threads with the garbage collector thread. Lock/Unlock macros are used so it's easier to make changes to the locks in the future. The 'dead thread list' lock is intended to replace the gc mutex. This doesn't have any practical ramifications. It simply makes it clearer what the purpose of the lock is. The gc will use this lock, instead of the gc mutex, to synchronize access to the dead list with other threads. Modify _pthread_exit() to use these two new locks instead of GIANT_LOCK, and also to properly lock and protect thread state changes, especially with respect to a joining thread. The gc thread was also re-arranged to be more organized and less nested. _pthread_join() was also modified to use the thread list locks. However, locking and unlocking here needs special care because a thread could find itself in a position where it's joining an exiting thread that is waiting on the dead list lock, which this thread (joiner) holds. If the joiner doesn't take care to lock *and* unlock in the same order they (the joiner and the joinee) could deadlock against each other. Approved by: re/blanket libthr
2003-05-25 08:31:33 +00:00
THREAD_LIST_LOCK;
- Add libthr but don't hook it up to the regular build yet. This is an adaptation of libc_r for the thr system call interface. This is beta quality code.
2003-04-01 03:46:29 +00:00
if (TAILQ_FIRST(&_thread_list) == curthread &&
TAILQ_NEXT(curthread, tle) == NULL)
/*
* This is the last thread, so it can exit
* now.
*/
f_done = 1;
Start locking up the active and dead threads lists. The active threads list is protected by a spinlock_t, but the dead list uses a pthread_mutex because it is necessary to synchronize other threads with the garbage collector thread. Lock/Unlock macros are used so it's easier to make changes to the locks in the future. The 'dead thread list' lock is intended to replace the gc mutex. This doesn't have any practical ramifications. It simply makes it clearer what the purpose of the lock is. The gc will use this lock, instead of the gc mutex, to synchronize access to the dead list with other threads. Modify _pthread_exit() to use these two new locks instead of GIANT_LOCK, and also to properly lock and protect thread state changes, especially with respect to a joining thread. The gc thread was also re-arranged to be more organized and less nested. _pthread_join() was also modified to use the thread list locks. However, locking and unlocking here needs special care because a thread could find itself in a position where it's joining an exiting thread that is waiting on the dead list lock, which this thread (joiner) holds. If the joiner doesn't take care to lock *and* unlock in the same order they (the joiner and the joinee) could deadlock against each other. Approved by: re/blanket libthr
2003-05-25 08:31:33 +00:00
THREAD_LIST_UNLOCK;
- Add libthr but don't hook it up to the regular build yet. This is an adaptation of libc_r for the thr system call interface. This is beta quality code.
2003-04-01 03:46:29 +00:00
/*
* Enter a loop to search for the first dead thread that
* has memory to free.
*/
for (pthread = TAILQ_FIRST(&_dead_list);
p_stack == NULL && pthread_cln == NULL && pthread != NULL;
pthread = TAILQ_NEXT(pthread, dle)) {
/* Don't destroy the initial thread. */
if (pthread == _thread_initial)
continue;
Start locking up the active and dead threads lists. The active threads list is protected by a spinlock_t, but the dead list uses a pthread_mutex because it is necessary to synchronize other threads with the garbage collector thread. Lock/Unlock macros are used so it's easier to make changes to the locks in the future. The 'dead thread list' lock is intended to replace the gc mutex. This doesn't have any practical ramifications. It simply makes it clearer what the purpose of the lock is. The gc will use this lock, instead of the gc mutex, to synchronize access to the dead list with other threads. Modify _pthread_exit() to use these two new locks instead of GIANT_LOCK, and also to properly lock and protect thread state changes, especially with respect to a joining thread. The gc thread was also re-arranged to be more organized and less nested. _pthread_join() was also modified to use the thread list locks. However, locking and unlocking here needs special care because a thread could find itself in a position where it's joining an exiting thread that is waiting on the dead list lock, which this thread (joiner) holds. If the joiner doesn't take care to lock *and* unlock in the same order they (the joiner and the joinee) could deadlock against each other. Approved by: re/blanket libthr
2003-05-25 08:31:33 +00:00
Sweep through pthread locking and use the new locking primitives for libthr.
2003-06-29 23:51:04 +00:00
THR_LOCK(&pthread->lock);
Start locking up the active and dead threads lists. The active threads list is protected by a spinlock_t, but the dead list uses a pthread_mutex because it is necessary to synchronize other threads with the garbage collector thread. Lock/Unlock macros are used so it's easier to make changes to the locks in the future. The 'dead thread list' lock is intended to replace the gc mutex. This doesn't have any practical ramifications. It simply makes it clearer what the purpose of the lock is. The gc will use this lock, instead of the gc mutex, to synchronize access to the dead list with other threads. Modify _pthread_exit() to use these two new locks instead of GIANT_LOCK, and also to properly lock and protect thread state changes, especially with respect to a joining thread. The gc thread was also re-arranged to be more organized and less nested. _pthread_join() was also modified to use the thread list locks. However, locking and unlocking here needs special care because a thread could find itself in a position where it's joining an exiting thread that is waiting on the dead list lock, which this thread (joiner) holds. If the joiner doesn't take care to lock *and* unlock in the same order they (the joiner and the joinee) could deadlock against each other. Approved by: re/blanket libthr
2003-05-25 08:31:33 +00:00
- Add libthr but don't hook it up to the regular build yet. This is an adaptation of libc_r for the thr system call interface. This is beta quality code.
2003-04-01 03:46:29 +00:00
/*
Start locking up the active and dead threads lists. The active threads list is protected by a spinlock_t, but the dead list uses a pthread_mutex because it is necessary to synchronize other threads with the garbage collector thread. Lock/Unlock macros are used so it's easier to make changes to the locks in the future. The 'dead thread list' lock is intended to replace the gc mutex. This doesn't have any practical ramifications. It simply makes it clearer what the purpose of the lock is. The gc will use this lock, instead of the gc mutex, to synchronize access to the dead list with other threads. Modify _pthread_exit() to use these two new locks instead of GIANT_LOCK, and also to properly lock and protect thread state changes, especially with respect to a joining thread. The gc thread was also re-arranged to be more organized and less nested. _pthread_join() was also modified to use the thread list locks. However, locking and unlocking here needs special care because a thread could find itself in a position where it's joining an exiting thread that is waiting on the dead list lock, which this thread (joiner) holds. If the joiner doesn't take care to lock *and* unlock in the same order they (the joiner and the joinee) could deadlock against each other. Approved by: re/blanket libthr
2003-05-25 08:31:33 +00:00
* Check if the stack was not specified by
* the caller to pthread_create() and has not
* been destroyed yet:
- Add libthr but don't hook it up to the regular build yet. This is an adaptation of libc_r for the thr system call interface. This is beta quality code.
2003-04-01 03:46:29 +00:00
*/
Decouple the thread stack [de]allocating functions from the 'dead threads list' lock. It's not really necessary and we don't need the added complexity or potential for deadlocks. Approved by: re/blanket libthr
2003-05-26 00:37:07 +00:00
STACK_LOCK;
Start locking up the active and dead threads lists. The active threads list is protected by a spinlock_t, but the dead list uses a pthread_mutex because it is necessary to synchronize other threads with the garbage collector thread. Lock/Unlock macros are used so it's easier to make changes to the locks in the future. The 'dead thread list' lock is intended to replace the gc mutex. This doesn't have any practical ramifications. It simply makes it clearer what the purpose of the lock is. The gc will use this lock, instead of the gc mutex, to synchronize access to the dead list with other threads. Modify _pthread_exit() to use these two new locks instead of GIANT_LOCK, and also to properly lock and protect thread state changes, especially with respect to a joining thread. The gc thread was also re-arranged to be more organized and less nested. _pthread_join() was also modified to use the thread list locks. However, locking and unlocking here needs special care because a thread could find itself in a position where it's joining an exiting thread that is waiting on the dead list lock, which this thread (joiner) holds. If the joiner doesn't take care to lock *and* unlock in the same order they (the joiner and the joinee) could deadlock against each other. Approved by: re/blanket libthr
2003-05-25 08:31:33 +00:00
if (pthread->attr.stackaddr_attr == NULL &&
pthread->stack != NULL) {
_thread_stack_free(pthread->stack,
pthread->attr.stacksize_attr,
pthread->attr.guardsize_attr);
pthread->stack = NULL;
- Add libthr but don't hook it up to the regular build yet. This is an adaptation of libc_r for the thr system call interface. This is beta quality code.
2003-04-01 03:46:29 +00:00
}
Decouple the thread stack [de]allocating functions from the 'dead threads list' lock. It's not really necessary and we don't need the added complexity or potential for deadlocks. Approved by: re/blanket libthr
2003-05-26 00:37:07 +00:00
STACK_UNLOCK;
Start locking up the active and dead threads lists. The active threads list is protected by a spinlock_t, but the dead list uses a pthread_mutex because it is necessary to synchronize other threads with the garbage collector thread. Lock/Unlock macros are used so it's easier to make changes to the locks in the future. The 'dead thread list' lock is intended to replace the gc mutex. This doesn't have any practical ramifications. It simply makes it clearer what the purpose of the lock is. The gc will use this lock, instead of the gc mutex, to synchronize access to the dead list with other threads. Modify _pthread_exit() to use these two new locks instead of GIANT_LOCK, and also to properly lock and protect thread state changes, especially with respect to a joining thread. The gc thread was also re-arranged to be more organized and less nested. _pthread_join() was also modified to use the thread list locks. However, locking and unlocking here needs special care because a thread could find itself in a position where it's joining an exiting thread that is waiting on the dead list lock, which this thread (joiner) holds. If the joiner doesn't take care to lock *and* unlock in the same order they (the joiner and the joinee) could deadlock against each other. Approved by: re/blanket libthr
2003-05-25 08:31:33 +00:00
/*
* If the thread has not been detached, leave
* it on the dead thread list.
*/
if ((pthread->attr.flags & PTHREAD_DETACHED) == 0) {
Sweep through pthread locking and use the new locking primitives for libthr.
2003-06-29 23:51:04 +00:00
THR_UNLOCK(&pthread->lock);
Start locking up the active and dead threads lists. The active threads list is protected by a spinlock_t, but the dead list uses a pthread_mutex because it is necessary to synchronize other threads with the garbage collector thread. Lock/Unlock macros are used so it's easier to make changes to the locks in the future. The 'dead thread list' lock is intended to replace the gc mutex. This doesn't have any practical ramifications. It simply makes it clearer what the purpose of the lock is. The gc will use this lock, instead of the gc mutex, to synchronize access to the dead list with other threads. Modify _pthread_exit() to use these two new locks instead of GIANT_LOCK, and also to properly lock and protect thread state changes, especially with respect to a joining thread. The gc thread was also re-arranged to be more organized and less nested. _pthread_join() was also modified to use the thread list locks. However, locking and unlocking here needs special care because a thread could find itself in a position where it's joining an exiting thread that is waiting on the dead list lock, which this thread (joiner) holds. If the joiner doesn't take care to lock *and* unlock in the same order they (the joiner and the joinee) could deadlock against each other. Approved by: re/blanket libthr
2003-05-25 08:31:33 +00:00
continue;
}
/* Remove this thread from the dead list: */
TAILQ_REMOVE(&_dead_list, pthread, dle);
/*
* Point to the thread structure that must
* be freed outside the locks:
*/
pthread_cln = pthread;
Sweep through pthread locking and use the new locking primitives for libthr.
2003-06-29 23:51:04 +00:00
THR_UNLOCK(&pthread->lock);
Don't hold the active thread list lock when signaling the gc thread. The dead list thread is sufficient for synchronization. Retire the arch_id (ldt array slot) in the gc thread instead of the doing it in the thread itself. Approved by: re/jhb
2003-05-29 20:46:53 +00:00
/*
* Retire the architecture specific id so it may be
* used for new threads.
*/
_retire_thread(pthread_cln->arch_id);
- Add libthr but don't hook it up to the regular build yet. This is an adaptation of libc_r for the thr system call interface. This is beta quality code.
2003-04-01 03:46:29 +00:00
}
/*
* Check if this is not the last thread and there is no
* memory to free this time around.
*/
if (!f_done && p_stack == NULL && pthread_cln == NULL) {
/* Get the current time. */
if (clock_gettime(CLOCK_REALTIME,&abstime) != 0)
PANIC("gc cannot get time");
/*
* Do a backup poll in 10 seconds if no threads
* die before then.
*/
abstime.tv_sec += 10;
/*
* Wait for a signal from a dying thread or a
* timeout (for a backup poll).
*/
if ((ret = pthread_cond_timedwait(&_gc_cond,
Start locking up the active and dead threads lists. The active threads list is protected by a spinlock_t, but the dead list uses a pthread_mutex because it is necessary to synchronize other threads with the garbage collector thread. Lock/Unlock macros are used so it's easier to make changes to the locks in the future. The 'dead thread list' lock is intended to replace the gc mutex. This doesn't have any practical ramifications. It simply makes it clearer what the purpose of the lock is. The gc will use this lock, instead of the gc mutex, to synchronize access to the dead list with other threads. Modify _pthread_exit() to use these two new locks instead of GIANT_LOCK, and also to properly lock and protect thread state changes, especially with respect to a joining thread. The gc thread was also re-arranged to be more organized and less nested. _pthread_join() was also modified to use the thread list locks. However, locking and unlocking here needs special care because a thread could find itself in a position where it's joining an exiting thread that is waiting on the dead list lock, which this thread (joiner) holds. If the joiner doesn't take care to lock *and* unlock in the same order they (the joiner and the joinee) could deadlock against each other. Approved by: re/blanket libthr
2003-05-25 08:31:33 +00:00
&dead_list_lock, &abstime)) != 0 && ret != ETIMEDOUT) {
Fix build breakage (on ia64) caused by a missing file descriptor to _thread_printf(). Use STDERR_FILENO as the file descriptor.
2003-04-20 02:56:12 +00:00
_thread_printf(STDERR_FILENO, "ret = %d", ret);
- Add libthr but don't hook it up to the regular build yet. This is an adaptation of libc_r for the thr system call interface. This is beta quality code.
2003-04-01 03:46:29 +00:00
PANIC("gc cannot wait for a signal");
}
}
/* Unlock the garbage collector mutex: */
Start locking up the active and dead threads lists. The active threads list is protected by a spinlock_t, but the dead list uses a pthread_mutex because it is necessary to synchronize other threads with the garbage collector thread. Lock/Unlock macros are used so it's easier to make changes to the locks in the future. The 'dead thread list' lock is intended to replace the gc mutex. This doesn't have any practical ramifications. It simply makes it clearer what the purpose of the lock is. The gc will use this lock, instead of the gc mutex, to synchronize access to the dead list with other threads. Modify _pthread_exit() to use these two new locks instead of GIANT_LOCK, and also to properly lock and protect thread state changes, especially with respect to a joining thread. The gc thread was also re-arranged to be more organized and less nested. _pthread_join() was also modified to use the thread list locks. However, locking and unlocking here needs special care because a thread could find itself in a position where it's joining an exiting thread that is waiting on the dead list lock, which this thread (joiner) holds. If the joiner doesn't take care to lock *and* unlock in the same order they (the joiner and the joinee) could deadlock against each other. Approved by: re/blanket libthr
2003-05-25 08:31:33 +00:00
DEAD_LIST_UNLOCK;
- Add libthr but don't hook it up to the regular build yet. This is an adaptation of libc_r for the thr system call interface. This is beta quality code.
2003-04-01 03:46:29 +00:00
/*
* If there is memory to free, do it now. The call to
* free() might block, so this must be done outside the
* locks.
*/
if (p_stack != NULL)
free(p_stack);
if (pthread_cln != NULL) {
if (pthread_cln->name != NULL) {
/* Free the thread name string. */
free(pthread_cln->name);
}
/*
* Free the memory allocated for the thread
* structure.
*/
free(pthread_cln);
}
}
return (NULL);
}
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