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Date: Mon, 25 Feb 2008 22:53:35 +0100 From: Pavel Machek <pavel@....cz> To: Gregory Haskins <ghaskins@...ell.com> Cc: mingo@...e.hu, a.p.zijlstra@...llo.nl, tglx@...utronix.de, rostedt@...dmis.org, linux-rt-users@...r.kernel.org, linux-kernel@...r.kernel.org, bill.huey@...il.com, kevin@...man.org, cminyard@...sta.com, dsingleton@...sta.com, dwalker@...sta.com, npiggin@...e.de, dsaxena@...xity.net, ak@...e.de, acme@...hat.com, gregkh@...e.de, sdietrich@...ell.com, pmorreale@...ell.com, mkohari@...ell.com Subject: Re: [(RT RFC) PATCH v2 2/9] sysctl for runtime-control of lateral mutex stealing Hi! > From: Sven-Thorsten Dietrich <sdietrich@...e.de> > > Add /proc/sys/kernel/lateral_steal, to allow switching on and off > equal-priority mutex stealing between threads. > > Signed-off-by: Sven-Thorsten Dietrich <sdietrich@...e.de> > --- > > kernel/rtmutex.c | 7 ++++++- > kernel/sysctl.c | 14 ++++++++++++++ > 2 files changed, 20 insertions(+), 1 deletions(-) > > diff --git a/kernel/rtmutex.c b/kernel/rtmutex.c > index 6624c66..cd39c26 100644 > --- a/kernel/rtmutex.c > +++ b/kernel/rtmutex.c > @@ -18,6 +18,10 @@ > > #include "rtmutex_common.h" > > +#ifdef CONFIG_RTLOCK_LATERAL_STEAL > +int rtmutex_lateral_steal __read_mostly = 1; > +#endif > + Ugly.. > /* > * lock->owner state tracking: > * > @@ -321,7 +325,8 @@ static inline int lock_is_stealable(struct task_struct *pendowner, int unfair) > if (current->prio > pendowner->prio) > return 0; > > - if (!unfair && (current->prio == pendowner->prio)) > + if (unlikely(current->prio == pendowner->prio) && > + !(unfair && rtmutex_lateral_steal)) > #endif But this is even worse, you are creating #ifdef maze here. Can you simply #define rtmutex_lateral_steal 0 in !CONFIG_RTLOCK_LATERAL_STEAL and let the optimizer fix this? > index c913d48..c24c53d 100644 > --- a/kernel/sysctl.c > +++ b/kernel/sysctl.c > @@ -175,6 +175,10 @@ extern struct ctl_table inotify_table[]; > int sysctl_legacy_va_layout; > #endif > > +#ifdef CONFIG_RTLOCK_LATERAL_STEAL > +extern int rtmutex_lateral_steal; > +#endif > + Try checkpatch. Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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