lkml.org 
[lkml]   [2011]   [Aug]   [15]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH 18/32] nohz/cpuset: Don't stop the tick if posix cpu timers are running
    Date
    If either a per thread or a per process posix cpu timer is running,
    don't stop the tick.

    TODO: restart the tick if it is stopped and a posix cpu timer is
    enqueued. Check we probably need a memory barrier for the per
    process posix timer that can be enqueued from another task
    of the group.

    Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
    Cc: Andrew Morton <akpm@linux-foundation.org>
    Cc: Anton Blanchard <anton@au1.ibm.com>
    Cc: Avi Kivity <avi@redhat.com>
    Cc: Ingo Molnar <mingo@elte.hu>
    Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
    Cc: Paul E . McKenney <paulmck@linux.vnet.ibm.com>
    Cc: Paul Menage <menage@google.com>
    Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
    Cc: Stephen Hemminger <shemminger@vyatta.com>
    Cc: Thomas Gleixner <tglx@linutronix.de>
    Cc: Tim Pepper <lnxninja@linux.vnet.ibm.com>
    ---
    include/linux/posix-timers.h | 1 +
    kernel/posix-cpu-timers.c | 12 ++++++++++++
    kernel/sched.c | 4 ++++
    3 files changed, 17 insertions(+), 0 deletions(-)

    diff --git a/include/linux/posix-timers.h b/include/linux/posix-timers.h
    index 959c141..5092cfd 100644
    --- a/include/linux/posix-timers.h
    +++ b/include/linux/posix-timers.h
    @@ -116,6 +116,7 @@ int posix_timer_event(struct k_itimer *timr, int si_private);
    void posix_cpu_timer_schedule(struct k_itimer *timer);

    void run_posix_cpu_timers(struct task_struct *task);
    +bool posix_cpu_timers_running(struct task_struct *tsk);
    void posix_cpu_timers_exit(struct task_struct *task);
    void posix_cpu_timers_exit_group(struct task_struct *task);

    diff --git a/kernel/posix-cpu-timers.c b/kernel/posix-cpu-timers.c
    index 58f405b..f284fa4 100644
    --- a/kernel/posix-cpu-timers.c
    +++ b/kernel/posix-cpu-timers.c
    @@ -6,6 +6,7 @@
    #include <linux/posix-timers.h>
    #include <linux/errno.h>
    #include <linux/math64.h>
    +#include <linux/cpuset.h>
    #include <asm/uaccess.h>
    #include <linux/kernel_stat.h>
    #include <trace/events/timer.h>
    @@ -1300,6 +1301,17 @@ static inline int fastpath_timer_check(struct task_struct *tsk)
    return 0;
    }

    +bool posix_cpu_timers_running(struct task_struct *tsk)
    +{
    + if (!task_cputime_zero(&tsk->cputime_expires))
    + return true;
    +
    + if (tsk->signal->cputimer.running)
    + return true;
    +
    + return false;
    +}
    +
    /*
    * This is called from the timer interrupt handler. The irq handler has
    * already updated our counts. We need to check if any timers fire now.
    diff --git a/kernel/sched.c b/kernel/sched.c
    index 8bf8280..78ea0a5 100644
    --- a/kernel/sched.c
    +++ b/kernel/sched.c
    @@ -71,6 +71,7 @@
    #include <linux/ctype.h>
    #include <linux/ftrace.h>
    #include <linux/slab.h>
    +#include <linux/posix-timers.h>

    #include <asm/tlb.h>
    #include <asm/irq_regs.h>
    @@ -2491,6 +2492,9 @@ bool cpuset_nohz_can_stop_tick(void)
    if (rcu_pending(cpu))
    return false;

    + if (posix_cpu_timers_running(current))
    + return false;
    +
    return true;
    }

    --
    1.7.5.4


    \
     
     \ /
      Last update: 2011-08-15 17:59    [W:0.026 / U:4.156 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site