From 49186d21ef2d87986bccaf0a7c45c48c91b265f3 Mon Sep 17 00:00:00 2001 From: Andi Kleen Date: Thu, 27 Jun 2013 11:15:06 -0700 Subject: Disable elision for any pthread_mutexattr_settype call PTHREAD_MUTEX_NORMAL requires deadlock for nesting, DEFAULT does not. Since glibc uses the same value (0) disable elision for any call to pthread_mutexattr_settype() with a 0 value. This implies that a program can disable elision by doing pthread_mutexattr_settype(&attr, PTHREAD_MUTEX_NORMAL) Based on a original proposal by Rich Felker. --- nptl/ChangeLog | 5 +++++ nptl/pthread_mutexattr_settype.c | 5 +++++ 2 files changed, 10 insertions(+) diff --git a/nptl/ChangeLog b/nptl/ChangeLog index 7f82b20..d32046e 100644 --- a/nptl/ChangeLog +++ b/nptl/ChangeLog @@ -1,4 +1,9 @@ 2013-07-02 Andi Kleen + + * pthread_mutexattr_settype.c (__pthread_mutexattr_settype): + Disable elision for PTHREAD_MUTEX_DEFAULT. + +2013-07-02 Andi Kleen Hongjiu Lu * pthread_mutex_lock.c diff --git a/nptl/pthread_mutexattr_settype.c b/nptl/pthread_mutexattr_settype.c index 7b476e9..a85cdcb 100644 --- a/nptl/pthread_mutexattr_settype.c +++ b/nptl/pthread_mutexattr_settype.c @@ -30,6 +30,11 @@ __pthread_mutexattr_settype (attr, kind) if (kind < PTHREAD_MUTEX_NORMAL || kind > PTHREAD_MUTEX_ADAPTIVE_NP) return EINVAL; + /* Cannot distinguish between DEFAULT and NORMAL. So any settype + call disables elision for now. */ + if (kind == PTHREAD_MUTEX_DEFAULT) + kind |= PTHREAD_MUTEX_NO_ELISION_NP; + iattr = (struct pthread_mutexattr *) attr; iattr->mutexkind = (iattr->mutexkind & PTHREAD_MUTEXATTR_FLAG_BITS) | kind; -- cgit v1.1