lkml.org 
[lkml]   [2017]   [Apr]   [20]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    Date
    From
    Subject[tip:smp/hotplug] cpu/hotplug: Use stop_machine_cpuslocked() in takedown_cpu()
    Commit-ID:  cdcb496b285dc8e9c544107d42bd60e5bc2feffa
    Gitweb: http://git.kernel.org/tip/cdcb496b285dc8e9c544107d42bd60e5bc2feffa
    Author: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
    AuthorDate: Tue, 18 Apr 2017 19:04:56 +0200
    Committer: Thomas Gleixner <tglx@linutronix.de>
    CommitDate: Thu, 20 Apr 2017 13:08:55 +0200

    cpu/hotplug: Use stop_machine_cpuslocked() in takedown_cpu()

    takedown_cpu() is a cpu hotplug function invoking stop_machine(). The cpu
    hotplug machinery holds the hotplug lock for write.

    stop_machine() invokes get_online_cpus() as well. This is correct, but
    prevents the conversion of the hotplug locking to a percpu rwsem.

    Use stop_machine_cpuslocked() to avoid the nested call.

    Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
    Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
    Cc: Peter Zijlstra <peterz@infradead.org>
    Cc: Steven Rostedt <rostedt@goodmis.org>
    Link: http://lkml.kernel.org/r/20170418170553.531067939@linutronix.de

    ---
    kernel/cpu.c | 2 +-
    1 file changed, 1 insertion(+), 1 deletion(-)

    diff --git a/kernel/cpu.c b/kernel/cpu.c
    index 92e5a91..f932e68 100644
    --- a/kernel/cpu.c
    +++ b/kernel/cpu.c
    @@ -701,7 +701,7 @@ static int takedown_cpu(unsigned int cpu)
    /*
    * So now all preempt/rcu users must observe !cpu_active().
    */
    - err = stop_machine(take_cpu_down, NULL, cpumask_of(cpu));
    + err = stop_machine_cpuslocked(take_cpu_down, NULL, cpumask_of(cpu));
    if (err) {
    /* CPU refused to die */
    irq_unlock_sparse();
    \
     
     \ /
      Last update: 2017-04-20 13:28    [W:2.791 / U:0.020 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site