lkml.org 
[lkml]   [2017]   [Jun]   [29]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH RFC 03/26] sched: Replace spin_unlock_wait() with lock/unlock pair
    Date
    There is no agreed-upon definition of spin_unlock_wait()'s semantics,
    and it appears that all callers could do just as well with a lock/unlock
    pair. This commit therefore replaces the spin_unlock_wait() call in
    do_task_dead() with spin_lock() followed immediately by spin_unlock().
    This should be safe from a performance perspective because the lock is
    this tasks ->pi_lock, and this is called only after the task exits.

    Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
    Cc: Ingo Molnar <mingo@redhat.com>
    Cc: Peter Zijlstra <peterz@infradead.org>
    Cc: Will Deacon <will.deacon@arm.com>
    Cc: Peter Zijlstra <peterz@infradead.org>
    Cc: Alan Stern <stern@rowland.harvard.edu>
    Cc: Andrea Parri <parri.andrea@gmail.com>
    Cc: Linus Torvalds <torvalds@linux-foundation.org>
    ---
    kernel/sched/core.c | 3 ++-
    1 file changed, 2 insertions(+), 1 deletion(-)

    diff --git a/kernel/sched/core.c b/kernel/sched/core.c
    index e91138fcde86..6dea3d9728c8 100644
    --- a/kernel/sched/core.c
    +++ b/kernel/sched/core.c
    @@ -3461,7 +3461,8 @@ void __noreturn do_task_dead(void)
    * is held by try_to_wake_up()
    */
    smp_mb();
    - raw_spin_unlock_wait(&current->pi_lock);
    + raw_spin_lock(&current->pi_lock);
    + raw_spin_unlock(&current->pi_lock);

    /* Causes final put_task_struct in finish_task_switch(): */
    __set_current_state(TASK_DEAD);
    --
    2.5.2
    \
     
     \ /
      Last update: 2017-06-30 02:10    [W:4.088 / U:0.188 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site