lkml.org 
[lkml]   [2008]   [Feb]   [25]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: [(RT RFC) PATCH v2 2/9] sysctl for runtime-control of lateral mutex stealing
    Hi!

    > From: Sven-Thorsten Dietrich <sdietrich@suse.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@suse.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


    \
     
     \ /
      Last update: 2008-02-25 22:55    [W:0.022 / U:31.972 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site