diff options
| author | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2017-06-29 12:08:26 -0700 |
|---|---|---|
| committer | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2017-08-11 13:09:14 -0700 |
| commit | 23a9b748a3d27f67cdb078fcb891a920285e75d9 (patch) | |
| tree | 3939c14a9385cb193210f2fb20e0edf4b96cf55b /kernel/sched | |
| parent | f274f1e72d7171c80c8c790040e47a23a74796b6 (diff) | |
| download | linux-23a9b748a3d27f67cdb078fcb891a920285e75d9.tar.bz2 | |
sched: Replace spin_unlock_wait() with lock/unlock pair
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: Alan Stern <stern@rowland.harvard.edu>
Cc: Andrea Parri <parri.andrea@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
[ paulmck: Drop smp_mb() based on Peter Zijlstra's analysis:
http://lkml.kernel.org/r/20170811144150.26gowhxte7ri5fpk@hirez.programming.kicks-ass.net ]
Diffstat (limited to 'kernel/sched')
| -rw-r--r-- | kernel/sched/core.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 17c667b427b4..5d22323ae099 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -3352,8 +3352,8 @@ void __noreturn do_task_dead(void) * To avoid it, we have to wait for releasing tsk->pi_lock which * is held by try_to_wake_up() */ - smp_mb(); - raw_spin_unlock_wait(¤t->pi_lock); + raw_spin_lock_irq(¤t->pi_lock); + raw_spin_unlock_irq(¤t->pi_lock); /* Causes final put_task_struct in finish_task_switch(): */ __set_current_state(TASK_DEAD); |