From mboxrd@z Thu Jan 1 00:00:00 1970 Resent-To: xenomai-core Resent-Message-Id: <48BBB22C.6080402@domain.hid> Message-ID: <48BBADB0.5020508@domain.hid> Date: Mon, 01 Sep 2008 10:54:08 +0200 From: Jan Kiszka MIME-Version: 1.0 References: <48BBA9E6.5070400@domain.hid> In-Reply-To: <48BBA9E6.5070400@domain.hid> Content-Type: text/plain; charset=ISO-8859-15 Content-Transfer-Encoding: 7bit Subject: [Xenomai-core] [RFC][PATCH 5/9] Allow lock stealing via pthread_mutex_trylock List-Id: "Xenomai life and development \(bug reports, patches, discussions\)" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: xenomai-core By calling into the kernel in the contended case and exploiting XN_NONBLOCK for xnsynch_sleep_on, this patch adds lock stealing support to pthread_mutex_trylock. The latter part may change if we decide to go for a dedicates xnsynch trylock service. Maybe we are even lucky and able to implement lock stealing purely with the help of the fast lock algorithm. But we first have to merge fast locks into xnsynch to see clearer. --- include/posix/syscall.h | 2 - ksrc/skins/posix/cond.c | 3 +- ksrc/skins/posix/mutex.c | 24 +++++++++++++---------- ksrc/skins/posix/mutex.h | 11 +++------- ksrc/skins/posix/syscall.c | 46 +++++++++++++++++++++++++++++++++++---------- src/skins/posix/mutex.c | 6 ++++- 6 files changed, 62 insertions(+), 30 deletions(-) Index: b/ksrc/skins/posix/cond.c =================================================================== --- a/ksrc/skins/posix/cond.c +++ b/ksrc/skins/posix/cond.c @@ -345,7 +345,8 @@ int pse51_cond_timedwait_epilogue(xnthre cond = shadow->cond; - err = pse51_mutex_timedlock_internal(cur, mutex, count, 0, XN_INFINITE); + err = pse51_mutex_timedlock_internal(cur, mutex, count, XN_RELATIVE, + XN_INFINITE); if (err == -EINTR) goto unlock_and_return; Index: b/ksrc/skins/posix/mutex.c =================================================================== --- a/ksrc/skins/posix/mutex.c +++ b/ksrc/skins/posix/mutex.c @@ -283,7 +283,7 @@ int pthread_mutex_destroy(pthread_mutex_ } int pse51_mutex_timedlock_break(struct __shadow_mutex *shadow, - int timed, xnticks_t abs_to) + xntmode_t timeout_mode, xnticks_t timeout) { xnthread_t *cur = xnpod_current_thread(); pse51_mutex_t *mutex; @@ -294,7 +294,8 @@ int pse51_mutex_timedlock_break(struct _ if (!xnthread_handle(cur)) return -EPERM; - err = pse51_mutex_timedlock_internal(cur, shadow, 1, timed, abs_to); + err = pse51_mutex_timedlock_internal(cur, shadow, 1, timeout_mode, + timeout); if (err != -EBUSY) goto unlock_and_return; @@ -306,12 +307,8 @@ int pse51_mutex_timedlock_break(struct _ xnlock_get_irqsave(&nklock, s); for (;;) { ++mutex->sleepers; - if (timed) - xnsynch_sleep_on(&mutex->synchbase, - abs_to, XN_REALTIME); - else - xnsynch_sleep_on(&mutex->synchbase, - XN_INFINITE, XN_RELATIVE); + xnsynch_sleep_on(&mutex->synchbase, timeout, + timeout_mode); --mutex->sleepers; if (xnthread_test_info(cur, XNBREAK)) { @@ -407,6 +404,12 @@ int pthread_mutex_trylock(pthread_mutex_ err = 0; } } + } else { + err = + -pse51_mutex_timedlock_internal(cur, shadow, 1, + XN_RELATIVE, XN_NONBLOCK); + if (err == ETIMEDOUT) + err = EBUSY; } cb_read_unlock(&shadow->lock, s); @@ -461,7 +464,8 @@ int pthread_mutex_lock(pthread_mutex_t * return EINVAL; do { - err = pse51_mutex_timedlock_break(shadow, 0, XN_INFINITE); + err = pse51_mutex_timedlock_break(shadow, XN_RELATIVE, + XN_INFINITE); } while (err == -EINTR); cb_read_unlock(&shadow->lock, s); @@ -514,7 +518,7 @@ int pthread_mutex_timedlock(pthread_mute return EINVAL; do { - err = pse51_mutex_timedlock_break(shadow, 1, + err = pse51_mutex_timedlock_break(shadow, XN_REALTIME, ts2ticks_ceil(to) + 1); } while (err == -EINTR); Index: b/ksrc/skins/posix/mutex.h =================================================================== --- a/ksrc/skins/posix/mutex.h +++ b/ksrc/skins/posix/mutex.h @@ -71,7 +71,7 @@ void pse51_mutex_pkg_cleanup(void); /* Internal mutex functions, exposed for use by syscall.c. */ int pse51_mutex_timedlock_break(struct __shadow_mutex *shadow, - int timed, xnticks_t to); + xntmode_t timeout_mode, xnticks_t timeout); int pse51_mutex_check_init(struct __shadow_mutex *shadow, const pthread_mutexattr_t *attr); @@ -120,8 +120,8 @@ pse51_mutex_trylock_internal(xnthread_t static inline int pse51_mutex_timedlock_internal(xnthread_t *cur, struct __shadow_mutex *shadow, unsigned count, - int timed, - xnticks_t abs_to) + xntmode_t timeout_mode, + xnticks_t timeout) { pse51_mutex_t *mutex; @@ -173,10 +173,7 @@ static inline int pse51_mutex_timedlock_ xnsynch_set_owner(&mutex->synchbase, owner); ++mutex->sleepers; - if (timed) - xnsynch_sleep_on(&mutex->synchbase, abs_to, XN_REALTIME); - else - xnsynch_sleep_on(&mutex->synchbase, XN_INFINITE, XN_RELATIVE); + xnsynch_sleep_on(&mutex->synchbase, timeout, timeout_mode); --mutex->sleepers; if (xnthread_test_info(cur, XNBREAK)) { Index: b/ksrc/skins/posix/syscall.c =================================================================== --- a/ksrc/skins/posix/syscall.c +++ b/ksrc/skins/posix/syscall.c @@ -957,7 +957,8 @@ static int __pthread_mutex_lock(struct p if (unlikely(cb_try_read_lock(&mx.shadow_mutex.lock, s))) return -EINVAL; - err = pse51_mutex_timedlock_break(&mx.shadow_mutex, 0, XN_INFINITE); + err = pse51_mutex_timedlock_break(&mx.shadow_mutex, XN_REALTIVE, + XN_INFINITE); cb_read_unlock(&mx.shadow_mutex.lock, s); @@ -991,8 +992,8 @@ static int __pthread_mutex_timedlock(str if (unlikely(cb_try_read_lock(&mx.shadow_mutex.lock, s))) return -EINVAL; - err = pse51_mutex_timedlock_break(&mx.shadow_mutex, - 1, ts2ticks_ceil(&ts) + 1); + err = pse51_mutex_timedlock_break(&mx.shadow_mutex, XN_REALTIME, + ts2ticks_ceil(&ts) + 1); cb_read_unlock(&mx.shadow_mutex.lock, s); @@ -1214,7 +1215,8 @@ static int __pthread_mutex_lock(struct p shadow = &mx.shadow_mutex; - err = pse51_mutex_timedlock_break(&mx.shadow_mutex, 0, XN_INFINITE); + err = pse51_mutex_timedlock_break(&mx.shadow_mutex, XN_RELATIVE, + XN_INFINITE); if (!err && __xn_safe_copy_to_user((void __user *) @@ -1247,8 +1249,8 @@ static int __pthread_mutex_timedlock(str shadow = &mx.shadow_mutex; - err = pse51_mutex_timedlock_break(&mx.shadow_mutex, - 1, ts2ticks_ceil(&ts) + 1); + err = pse51_mutex_timedlock_break(&mx.shadow_mutex, XN_REALTIME, + ts2ticks_ceil(&ts) + 1); if (!err && __xn_safe_copy_to_user((void __user *) @@ -1260,6 +1262,31 @@ static int __pthread_mutex_timedlock(str return err; } +static int __pthread_mutex_trylock(struct pt_regs *regs) +{ + xnthread_t *cur = xnpod_current_thread(); + union __xeno_mutex mx, *umx; + int err; + + umx = (union __xeno_mutex *)__xn_reg_arg1(regs); + + if (__xn_safe_copy_from_user(&mx.shadow_mutex, + (void __user *)&umx->shadow_mutex, + sizeof(mx.shadow_mutex))) + return -EFAULT; + + err = pse51_mutex_timedlock_internal(cur, &mx.shadow_mutex, 1, + XN_RELATIVE, XN_NONBLOCK); + + if (!err && + __xn_safe_copy_to_user((void __user *)&umx->shadow_mutex.lockcnt, + &mx.shadow_mutex.lockcnt, + sizeof(umx->shadow_mutex.lockcnt))) + return -EFAULT; + + return err; +} + static int __pthread_mutex_unlock(struct pt_regs *regs) { xnthread_t *cur = xnpod_current_thread(); @@ -2695,11 +2722,7 @@ static xnsysent_t __systab[] = { [__pse51_mutex_lock] = {&__pthread_mutex_lock, __xn_exec_primary}, [__pse51_mutex_timedlock] = {&__pthread_mutex_timedlock, __xn_exec_primary}, -#ifndef CONFIG_XENO_FASTSEM [__pse51_mutex_trylock] = {&__pthread_mutex_trylock, __xn_exec_primary}, -#else - [__pse51_check_init] = {&__pthread_mutex_check_init, __xn_exec_any}, -#endif [__pse51_mutex_unlock] = {&__pthread_mutex_unlock, __xn_exec_primary|__xn_exec_norestart}, [__pse51_cond_init] = {&__pthread_cond_init, __xn_exec_any}, [__pse51_cond_destroy] = {&__pthread_cond_destroy, __xn_exec_any}, @@ -2763,6 +2786,9 @@ static xnsysent_t __systab[] = { [__pse51_condattr_setpshared] = {&__pthread_condattr_setpshared, __xn_exec_any}, [__pse51_select] = {&__select, __xn_exec_primary}, +#ifdef CONFIG_XENO_FASTSEM + [__pse51_check_init] = {&__pthread_mutex_check_init, __xn_exec_any}, +#endif }; static void __shadow_delete_hook(xnthread_t *thread) Index: b/src/skins/posix/mutex.c =================================================================== --- a/src/skins/posix/mutex.c +++ b/src/skins/posix/mutex.c @@ -301,7 +301,11 @@ int __wrap_pthread_mutex_trylock(pthread ++shadow->lockcnt; err = 0; } - } + } else + do { + err = XENOMAI_SKINCALL1(__pse51_muxid, + __pse51_mutex_trylock, shadow); + } while (err == -EINTR); out: cb_read_unlock(&shadow->lock, s); Index: b/include/posix/syscall.h =================================================================== --- a/include/posix/syscall.h +++ b/include/posix/syscall.h @@ -46,7 +46,6 @@ #define __pse51_mutex_lock 20 #define __pse51_mutex_timedlock 21 #define __pse51_mutex_trylock 22 -#define __pse51_check_init __pse51_mutex_trylock #define __pse51_mutex_unlock 23 #define __pse51_cond_init 24 #define __pse51_cond_destroy 25 @@ -102,6 +101,7 @@ #define __pse51_thread_getschedparam 75 #define __pse51_thread_kill 76 #define __pse51_select 77 +#define __pse51_check_init 78 #ifdef __KERNEL__