freebsd-dev/lib/libthr/thread/thr_stack.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

256 lines
9.1 KiB
C

/*
* Copyright (c) 2001 Daniel Eischen <deischen@freebsd.org>
* Copyright (c) 2000-2001 Jason Evans <jasone@freebsd.org>
* 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.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHORS 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 AUTHORS 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 <sys/mman.h>
#include <sys/queue.h>
#include <stdlib.h>
#include <pthread.h>
#include "thr_private.h"
/* Spare thread stack. */
struct stack {
LIST_ENTRY(stack) qe; /* Stack queue linkage. */
size_t stacksize; /* Stack size (rounded up). */
size_t guardsize; /* Guard size. */
void *stackaddr; /* Stack address. */
};
/*
* Default sized (stack and guard) spare stack queue. Stacks are cached
* to avoid additional complexity managing mmap()ed stack regions. Spare
* stacks are used in LIFO order to increase cache locality.
*/
static LIST_HEAD(, stack) dstackq = LIST_HEAD_INITIALIZER(dstackq);
/*
* Miscellaneous sized (non-default stack and/or guard) spare stack queue.
* Stacks are cached to avoid additional complexity managing mmap()ed
* stack regions. This list is unordered, since ordering on both stack
* size and guard size would be more trouble than it's worth. Stacks are
* allocated from this cache on a first size match basis.
*/
static LIST_HEAD(, stack) mstackq = LIST_HEAD_INITIALIZER(mstackq);
/**
* Base address of the last stack allocated (including its red zone, if
* there is one). Stacks are allocated contiguously, starting beyond the
* top of the main stack. When a new stack is created, a red zone is
* typically created (actually, the red zone is mapped with PROT_NONE) above
* the top of the stack, such that the stack will not be able to grow all
* the way to the bottom of the next stack. This isn't fool-proof. It is
* possible for a stack to grow by a large amount, such that it grows into
* the next stack, and as long as the memory within the red zone is never
* accessed, nothing will prevent one thread stack from trouncing all over
* the next.
*
* low memory
* . . . . . . . . . . . . . . . . . .
* | |
* | stack 3 | start of 3rd thread stack
* +-----------------------------------+
* | |
* | Red Zone (guard page) | red zone for 2nd thread
* | |
* +-----------------------------------+
* | stack 2 - _thr_stack_default | top of 2nd thread stack
* | |
* | |
* | |
* | |
* | stack 2 |
* +-----------------------------------+ <-- start of 2nd thread stack
* | |
* | Red Zone | red zone for 1st thread
* | |
* +-----------------------------------+
* | stack 1 - _thr_stack_default | top of 1st thread stack
* | |
* | |
* | |
* | |
* | stack 1 |
* +-----------------------------------+ <-- start of 1st thread stack
* | | (initial value of last_stack)
* | Red Zone |
* | | red zone for main thread
* +-----------------------------------+
* | USRSTACK - _thr_stack_initial | top of main thread stack
* | | ^
* | | |
* | | |
* | | | stack growth
* | |
* +-----------------------------------+ <-- start of main thread stack
* (USRSTACK)
* high memory
*
*/
static void *last_stack = NULL;
/*
* Round size up to the nearest multiple of
* _thr_page_size.
*/
static inline size_t
round_up(size_t size)
{
if (size % _thr_page_size != 0)
size = ((size / _thr_page_size) + 1) *
_thr_page_size;
return size;
}
int
_thr_stack_alloc(struct pthread_attr *attr)
{
struct pthread *curthread = _get_curthread();
struct stack *spare_stack;
size_t stacksize;
size_t guardsize;
char *stackaddr;
/*
* Round up stack size to nearest multiple of _thr_page_size so
* that mmap() * will work. If the stack size is not an even
* multiple, we end up initializing things such that there is
* unused space above the beginning of the stack, so the stack
* sits snugly against its guard.
*/
stacksize = round_up(attr->stacksize_attr);
guardsize = round_up(attr->guardsize_attr);
attr->stackaddr_attr = NULL;
attr->flags &= ~THR_STACK_USER;
/*
* Use the garbage collector lock for synchronization of the
* spare stack lists and allocations from usrstack.
*/
THREAD_LIST_LOCK(curthread);
/*
* If the stack and guard sizes are default, try to allocate a stack
* from the default-size stack cache:
*/
if ((stacksize == THR_STACK_DEFAULT) &&
(guardsize == _thr_guard_default)) {
if ((spare_stack = LIST_FIRST(&dstackq)) != NULL) {
/* Use the spare stack. */
LIST_REMOVE(spare_stack, qe);
attr->stackaddr_attr = spare_stack->stackaddr;
}
}
/*
* The user specified a non-default stack and/or guard size, so try to
* allocate a stack from the non-default size stack cache, using the
* rounded up stack size (stack_size) in the search:
*/
else {
LIST_FOREACH(spare_stack, &mstackq, qe) {
if (spare_stack->stacksize == stacksize &&
spare_stack->guardsize == guardsize) {
LIST_REMOVE(spare_stack, qe);
attr->stackaddr_attr = spare_stack->stackaddr;
break;
}
}
}
if (attr->stackaddr_attr != NULL) {
/* A cached stack was found. Release the lock. */
THREAD_LIST_UNLOCK(curthread);
}
else {
/* Allocate a stack from usrstack. */
if (last_stack == NULL)
last_stack = _usrstack - _thr_stack_initial -
_thr_guard_default;
/* Allocate a new stack. */
stackaddr = last_stack - stacksize - guardsize;
/*
* Even if stack allocation fails, we don't want to try to
* use this location again, so unconditionally decrement
* last_stack. Under normal operating conditions, the most
* likely reason for an mmap() error is a stack overflow of
* the adjacent thread stack.
*/
last_stack -= (stacksize + guardsize);
/* Release the lock before mmap'ing it. */
THREAD_LIST_UNLOCK(curthread);
/* Map the stack and guard page together, and split guard
page from allocated space: */
if ((stackaddr = mmap(stackaddr, stacksize+guardsize,
PROT_READ | PROT_WRITE, MAP_STACK,
-1, 0)) != MAP_FAILED &&
(guardsize == 0 ||
mprotect(stackaddr, guardsize, PROT_NONE) == 0)) {
stackaddr += guardsize;
} else {
if (stackaddr != MAP_FAILED)
munmap(stackaddr, stacksize + guardsize);
stackaddr = NULL;
}
attr->stackaddr_attr = stackaddr;
}
if (attr->stackaddr_attr != NULL)
return (0);
else
return (-1);
}
/* This function must be called with _thread_list_lock held. */
void
_thr_stack_free(struct pthread_attr *attr)
{
struct stack *spare_stack;
if ((attr != NULL) && ((attr->flags & THR_STACK_USER) == 0)
&& (attr->stackaddr_attr != NULL)) {
spare_stack = (attr->stackaddr_attr + attr->stacksize_attr
- sizeof(struct stack));
spare_stack->stacksize = round_up(attr->stacksize_attr);
spare_stack->guardsize = round_up(attr->guardsize_attr);
spare_stack->stackaddr = attr->stackaddr_attr;
if (spare_stack->stacksize == THR_STACK_DEFAULT &&
spare_stack->guardsize == _thr_guard_default) {
/* Default stack/guard size. */
LIST_INSERT_HEAD(&dstackq, spare_stack, qe);
} else {
/* Non-default stack/guard size. */
LIST_INSERT_HEAD(&mstackq, spare_stack, qe);
}
attr->stackaddr_attr = NULL;
}
}