freebsd-dev/lib/libthr/thread/thr_spinlock.c
David Xu a091d823ad Import my recent 1:1 threading working. some features improved includes:
1. fast simple type mutex.
 2. __thread tls works.
 3. asynchronous cancellation works ( using signal ).
 4. thread synchronization is fully based on umtx, mainly, condition
    variable and other synchronization objects were rewritten by using
    umtx directly. those objects can be shared between processes via
    shared memory, it has to change ABI which does not happen yet.
 5. default stack size is increased to 1M on 32 bits platform, 2M for
    64 bits platform.
As the result, some mysql super-smack benchmarks show performance is
improved massivly.

Okayed by: jeff, mtm, rwatson, scottl
2005-04-02 01:20:00 +00:00

126 lines
3.7 KiB
C

/*
* Copyright (c) 1997 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.
*
* $FreeBSD$
*
*/
#include <sys/types.h>
#include <pthread.h>
#include <libc_private.h>
#include <spinlock.h>
#include "thr_private.h"
#define MAX_SPINLOCKS 20
/*
* These data structures are used to trace all spinlocks
* in libc.
*/
struct spinlock_extra {
spinlock_t *owner;
};
static umtx_t spinlock_static_lock;
static struct spinlock_extra extra[MAX_SPINLOCKS];
static int spinlock_count;
static int initialized;
static void init_spinlock(spinlock_t *lck);
/*
* These are for compatability only. Spinlocks of this type
* are deprecated.
*/
void
_spinunlock(spinlock_t *lck)
{
THR_UMTX_UNLOCK(_get_curthread(), (umtx_t *)&lck->access_lock);
}
void
_spinlock(spinlock_t *lck)
{
if (!__isthreaded)
PANIC("Spinlock called when not threaded.");
if (!initialized)
PANIC("Spinlocks not initialized.");
if (lck->fname == NULL)
init_spinlock(lck);
THR_UMTX_LOCK(_get_curthread(), (umtx_t *)&lck->access_lock);
}
void
_spinlock_debug(spinlock_t *lck, char *fname, int lineno)
{
_spinlock(lck);
}
static void
init_spinlock(spinlock_t *lck)
{
static int count = 0;
THR_UMTX_LOCK(_get_curthread(), &spinlock_static_lock);
if ((lck->fname == NULL) && (spinlock_count < MAX_SPINLOCKS)) {
lck->fname = (char *)&extra[spinlock_count];
extra[spinlock_count].owner = lck;
spinlock_count++;
}
THR_UMTX_UNLOCK(_get_curthread(), &spinlock_static_lock);
if (lck->fname == NULL && ++count < 5)
stderr_debug("Warning: exceeded max spinlocks");
}
void
_thr_spinlock_init(void)
{
int i;
_thr_umtx_init(&spinlock_static_lock);
if (initialized != 0) {
/*
* called after fork() to reset state of libc spin locks,
* it is not quite right since libc may be in inconsistent
* state, resetting the locks to allow current thread to be
* able to hold them may not help things too much, but
* anyway, we do our best.
* it is better to do pthread_atfork in libc.
*/
for (i = 0; i < spinlock_count; i++)
_thr_umtx_init((umtx_t *)&extra[i].owner->access_lock);
} else {
initialized = 1;
}
}