From 31fb174dd295e50f7c5cf18d31fcfd5fe5a063b7 Mon Sep 17 00:00:00 2001 From: Rich Felker Date: Tue, 8 Nov 2016 12:09:05 -0500 Subject: add limited pthread_setattr_default_np API to set stack size defaults MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit based on patch by Timo Teräs: While generally this is a bad API, it is the only existing API to affect c++ (std::thread) and c11 (thrd_create) thread stack size. This patch allows applications only to increate stack and guard page sizes. --- include/pthread.h | 2 ++ src/thread/pthread_create.c | 12 +++++++---- src/thread/pthread_setattr_default_np.c | 35 +++++++++++++++++++++++++++++++++ 3 files changed, 45 insertions(+), 4 deletions(-) create mode 100644 src/thread/pthread_setattr_default_np.c diff --git a/include/pthread.h b/include/pthread.h index 94ef919c..bba9587e 100644 --- a/include/pthread.h +++ b/include/pthread.h @@ -215,6 +215,8 @@ int pthread_getaffinity_np(pthread_t, size_t, struct cpu_set_t *); int pthread_setaffinity_np(pthread_t, size_t, const struct cpu_set_t *); int pthread_getattr_np(pthread_t, pthread_attr_t *); int pthread_setname_np(pthread_t, const char *); +int pthread_getattr_default_np(pthread_attr_t *); +int pthread_setattr_default_np(const pthread_attr_t *); int pthread_tryjoin_np(pthread_t, void **); int pthread_timedjoin_np(pthread_t, void **, const struct timespec *); #endif diff --git a/src/thread/pthread_create.c b/src/thread/pthread_create.c index e8d4a635..49f2f729 100644 --- a/src/thread/pthread_create.c +++ b/src/thread/pthread_create.c @@ -163,6 +163,8 @@ static void *dummy_tsd[1] = { 0 }; weak_alias(dummy_tsd, __pthread_tsd_main); volatile int __block_new_threads = 0; +size_t __default_stacksize = DEFAULT_STACK_SIZE; +size_t __default_guardsize = DEFAULT_GUARD_SIZE; static FILE *volatile dummy_file = 0; weak_alias(dummy_file, __stdin_used); @@ -186,10 +188,7 @@ int __pthread_create(pthread_t *restrict res, const pthread_attr_t *restrict att | CLONE_THREAD | CLONE_SYSVSEM | CLONE_SETTLS | CLONE_PARENT_SETTID | CLONE_CHILD_CLEARTID | CLONE_DETACHED; int do_sched = 0; - pthread_attr_t attr = { - ._a_stacksize = DEFAULT_STACK_SIZE, - ._a_guardsize = DEFAULT_GUARD_SIZE, - }; + pthread_attr_t attr = { 0 }; if (!libc.can_do_threads) return ENOSYS; self = __pthread_self(); @@ -207,6 +206,11 @@ int __pthread_create(pthread_t *restrict res, const pthread_attr_t *restrict att if (attrp && !c11) attr = *attrp; __acquire_ptc(); + if (!attrp || c11) { + attr._a_stacksize = __default_stacksize; + attr._a_guardsize = __default_guardsize; + } + if (__block_new_threads) __wait(&__block_new_threads, 0, 1, 1); if (attr._a_stackaddr) { diff --git a/src/thread/pthread_setattr_default_np.c b/src/thread/pthread_setattr_default_np.c new file mode 100644 index 00000000..ffd2712b --- /dev/null +++ b/src/thread/pthread_setattr_default_np.c @@ -0,0 +1,35 @@ +#include "pthread_impl.h" +#include + +extern size_t __default_stacksize; +extern size_t __default_guardsize; + +int pthread_setattr_default_np(const pthread_attr_t *attrp) +{ + /* Reject anything in the attr object other than stack/guard size. */ + pthread_attr_t tmp = *attrp, zero = { 0 }; + tmp._a_stacksize = 0; + tmp._a_guardsize = 0; + if (memcmp(&tmp, &zero, sizeof tmp)) + return EINVAL; + + __inhibit_ptc(); + if (attrp->_a_stacksize >= __default_stacksize) + __default_stacksize = attrp->_a_stacksize; + if (attrp->_a_guardsize >= __default_guardsize) + __default_guardsize = attrp->_a_guardsize; + __release_ptc(); + + return 0; +} + +int pthread_getattr_default_np(pthread_attr_t *attrp) +{ + __acquire_ptc(); + *attrp = (pthread_attr_t) { + ._a_stacksize = __default_stacksize, + ._a_guardsize = __default_guardsize, + }; + __release_ptc(); + return 0; +} -- cgit v1.2.1