/* * 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: src/lib/libpthread/thread/thr_stack.c,v 1.9 2004/10/06 08:11:07 davidxu Exp $ */ #include <sys/types.h> #include <sys/mman.h> #include <sys/queue.h> #include <sys/time.h> #include <sys/resource.h> #include <sys/sysctl.h> #include <machine/tls.h> #include <machine/vmparam.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); /* * Thread stack base for mmap() hint, starts * at _usrstack - kern.maxssiz - kern.maxthrssiz */ static char *base_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(pthread_attr_t attr) { pthread_t curthread = tls_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 { /* * Calculate base_stack on first use (race ok). * If base _stack */ if (base_stack == NULL) { int64_t maxssiz; int64_t maxthrssiz; struct rlimit rl; size_t len; if (getrlimit(RLIMIT_STACK, &rl) == 0) maxssiz = rl.rlim_max; else maxssiz = MAXSSIZ; len = sizeof(maxssiz); sysctlbyname("kern.maxssiz", &maxssiz, &len, NULL, 0); len = sizeof(maxthrssiz); if (sysctlbyname("kern.maxthrssiz", &maxthrssiz, &len, NULL, 0) < 0) { maxthrssiz = MAXTHRSSIZ; } base_stack = _usrstack - maxssiz - maxthrssiz; } /* Release the lock before mmap'ing it. */ THREAD_LIST_UNLOCK(curthread); /* * Map the stack and guard page together then split the * guard page from allocated space. * * We no longer use MAP_STACK and we define an area far * away from the default user stack (even though this will * cost us another few 4K page-table pages). DFly no longer * allows new MAP_STACK mappings to be made inside ungrown * portions of existing mappings. */ stackaddr = mmap(base_stack, stacksize + guardsize, PROT_READ | PROT_WRITE, MAP_ANON | MAP_PRIVATE, -1, 0); if (stackaddr != MAP_FAILED && guardsize) { if (mmap(stackaddr, guardsize, 0, MAP_ANON | MAP_FIXED, -1, 0) == MAP_FAILED) { munmap(stackaddr, stacksize + guardsize); stackaddr = MAP_FAILED; } else { stackaddr += guardsize; } } if (stackaddr == MAP_FAILED) 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(pthread_attr_t attr) { struct stack *spare_stack; if ((attr != NULL) && ((attr->flags & THR_STACK_USER) == 0) && (attr->stackaddr_attr != NULL)) { spare_stack = (struct stack *)((char *)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; } } void _thr_stack_cleanup(void) { struct stack *spare; while ((spare = LIST_FIRST(&dstackq)) != NULL) { LIST_REMOVE(spare, qe); munmap(spare->stackaddr, spare->stacksize + spare->guardsize); } }
